Surgical navigation system and method

Abstract

The present disclosure generally relates to surgical systems. The surgical system may generally include one or more surgical instrument assemblies and / or a surgical navigation system. The surgical instrument assemblies may include tracking devices trackable by the surgical navigation system. Additionally, the surgical system may be configurable to allow a user to define one or more alert zones relative to a patient's anatomy and / or surgical path. The surgical system may further include an alert device in communication with the surgical navigation system, which may be configurable to provide a user-perceptible alert to a surgeon or medical professional based on the position of the surgical instrument relative to the defined alert zones and / or surgical path as determined by the surgical navigation system.

Description

[Background technology]

[0001] In modern surgery, some of the most important tools available to medical professionals are powered surgical instruments, such as cordless drills, saws, wire drivers, high-speed drills, and ultrasonic handpieces. These surgical instruments often have a motor and / or processor built into the handpiece or housing. Surgical instruments may include attachment mechanisms that accept cutting attachments designed to be applied to a surgical site to perform a specific medical procedure. For example, a surgical drill may use cutting attachments, such as drill bits, burrs, or reamers, to drill holes in tissue or selectively remove tissue, such as bone. The availability of powered surgical instruments on patients reduces the physical strain on surgeons when performing medical procedures on patients. Furthermore, powered surgical instruments allow most surgical procedures to be performed more quickly and accurately than their traditional manual counterparts.

[0002] Surgical navigation systems can help surgeons guide surgical instruments during surgical procedures, such as sinus, spinal, or cranial surgery. Such procedures may involve inserting surgical instruments into the surgical site, traversing a surgical path from the surgical site to the surgical target area, and manipulating the surgical target area. Some surgical navigation systems include a display that overlays the position of the surgical instruments onto one or more two-dimensional representations of the patient (e.g., CT or MRI images). While this system allows the surgeon to determine the location of the surgical instruments, it does not determine whether the surgical instruments are correctly navigating the surgical path or manipulating the surgical target area. As a result, in some cases, the surgical instruments may deviate from the surgical path or the surgical target area. At the same time, accurate navigation of surgical instruments is important because critical anatomical features may be close to the surgical path or the surgical target area. It is important to recognize that surgical instruments may be off course and / or approach critical anatomical features. Therefore, there is a need in the art to identify and notify medical professionals when a surgical instrument has gone off course and / or may be approaching a critical anatomical area. Summary of the Invention

[0003] The present disclosure generally relates to surgical systems. The surgical system may generally include one or more surgical instrument assemblies and / or a surgical navigation system. The surgical instrument assemblies may include tracking devices trackable by the surgical navigation system. Additionally, the surgical system may be configurable to allow a user to define one or more alert zones relative to a patient's anatomy and / or surgical path. The surgical system may further include an alert device in communication with the surgical navigation system, which may be configurable to provide a user-perceptible alert to a surgeon or medical professional based on the position of the surgical instrument relative to the defined alert zones and / or surgical path as determined by the surgical navigation system.

[0004] An exemplary configuration provides a surgical system configured to enable a medical professional to define alert zones relative to critical structures of a patient in a known coordinate system to assist the medical professional in performing surgery on the patient. The surgical system also includes a navigation system. The system further includes a control console, which may include a control processor in communication with the navigation system. The system further includes a high-speed surgical instrument including a burr, which may include a variable-speed motor in communication with the control processor, the variable-speed motor configured to rotate the burr at a first cutting speed greater than 70,000 revolutions per minute and a second cutting speed less than 70,000 revolutions per minute and greater than 60,000 revolutions per minute. The system also includes a foot switch in communication with the control processor for controlling operation of the variable-speed motor of the high-speed surgical instrument. The system further includes a configuration in which the navigation system is configured to actively determine the position of the burr relative to the alert zones in the known coordinate system. The system further includes a configuration where, when the navigation system determines that the bur has entered an alert zone, the navigation system sends a signal to the control processor to operate the variable speed motor of the high-speed surgical instrument to transition the rotation of the bur from the first cutting speed to the second cutting speed, and where the transition of the bur from the first cutting speed to the second cutting speed causes a perceptible change in the bur transitioning from the first cutting speed to the second cutting speed, thereby notifying a medical professional that the bur has entered the alert zone.

[0005] In another exemplary configuration, a surgical system allows for defining alert zones relative to critical structures in a known coordinate system to assist a medical professional in performing surgery on a patient. The surgical system also includes a navigation system. The system also includes a high-speed surgical instrument, which may include a burr and a variable speed motor configured to rotate the burr. The system also includes a control console, which may include a control processor, the control processor configured to communicate with the variable speed motor of the high-speed surgical instrument and to receive data from the navigation system. The system also includes a footswitch, which may include a tactile alert device, in communication with the control processor to control operation of the variable speed motor of the high-speed surgical burr. The system also includes a configuration in which the navigation system is configured to determine a position of the burr relative to the alert zone and send data indicative of the position of the burr relative to the alert zone to the control processor, and the control processor is configured to operate the tactile alert device of the footswitch to provide a notification to a medical professional based on the position of the burr relative to the alert zone in the known coordinate system.

[0006] In yet another exemplary configuration, a surgical system for use by a medical professional in a procedure on a patient may also include a surgical tool assembly, the surgical tool assembly including a control console having a processor, a handpiece in communication with the processor of the control console, the handpiece coupled to an end effector and a variable speed motor that drives the end effector, a switch operable by a medical professional between a first position and a second position to control energization of the variable speed motor, and a switch sensor configured to detect the position of the switch and communicate a first signal indicative of the position of the switch to the processor. The system also includes a navigation system in communication with the processor, the navigation system configured to actively determine a position of the end effector relative to a first boundary defined in a known coordinate system. This system also includes a configuration in which the navigation system is configured to communicate a second signal to the processor to de-energize the variable speed motor based on the position of the end effector relative to the first boundary in the known coordinate system. The system also includes a configuration where, upon de-energizing the handpiece, the processor prevents re-energization of the variable speed motor while the end effector remains in a first position until a subsequent first signal is received from the switch sensor indicating that a medical professional has actuated the position of the switch while the end effector remains in a first position.

[0007] In yet another exemplary configuration, a surgical system allows for defining an alert zone in a known coordinate system to assist a medical professional in performing surgery on a patient. The surgical system also includes a navigation system. The system also includes a handheld surgical instrument coupled to an end effector, the handheld surgical instrument having a motor configured to rotate the end effector. The system also includes a control processor disposed within the handheld surgical instrument, the control processor communicating with the motor and configured to receive data from the navigation system. The system also includes a trigger disposed on the handheld surgical instrument, the trigger communicating with the control processor to control operation of the motor of the surgical instrument. The system also includes a case where the trigger can include a tactile alert device. The system also includes a case where the navigation system is configured to send data to the control processor that the end effector has entered an alert zone, and the control processor is configured to operate the tactile alert device of the trigger to notify a medical professional when the end effector has entered the alert zone.

[0008] In yet another exemplary configuration, a surgical system for use by a medical professional in a surgery on a patient includes a handheld surgical instrument configured to drive an end effector, the handheld surgical instrument may include a variable speed motor to rotate the end effector, a trigger operable by a medical professional between a first position and a second position, and a trigger sensor configured to detect the position of the trigger and output a first signal indicative of the position of the trigger. The system also includes a rechargeable battery module removably coupled to the handheld surgical instrument, the rechargeable battery module may include a transceiver configured to send and receive signals, and a battery processor in communication with the transceiver and with the trigger sensor, the battery processor configured to selectively provide power to the variable speed motor of the handheld surgical instrument based at least in part on the first signal indicative of the position of the trigger. The system also includes a navigation system in communication with the battery processor via the transceiver, the navigation system configured to actively determine a position of the end effector relative to a first boundary defined with respect to a known coordinate system. The system also includes where the navigation system is configured to communicate a second signal to the battery processor to limit power to the handheld surgical instrument based on the position of the end effector and the first boundary in a known coordinate system. The system also includes where, when the battery processor is limiting power to the handheld surgical instrument, the battery processor is configured to prevent energization of the variable speed motor until a subsequent first signal is received from the trigger sensor indicating that a medical professional has manipulated the position of the trigger.

[0009] In yet another exemplary configuration, a surgical system for use by a medical professional in a procedure on a patient includes a handheld surgical instrument configured to drive an end effector, the handheld surgical instrument may include a variable speed motor, a trigger operable by the medical professional between a first position and a second position, and a handpiece processor configured to control energization of the variable speed motor based at least in part on the position of the trigger. The system also includes a rechargeable battery module removably coupled to the handheld surgical instrument, the rechargeable battery module may include a transceiver configured to send and receive signals and a battery processor in communication with the transceiver, the battery processor configured to energize and de-energize the handheld surgical instrument. The system also includes a navigation system in communication with the battery processor via the transceiver, the navigation system configured to actively determine a position of the handheld surgical instrument relative to a boundary in a known coordinate system. The system also includes where the navigation system is configured to communicate a first signal to the battery processor to temporarily de-energize the handheld surgical instrument based on the position of the end effector relative to the boundary in the known coordinate system. The system also includes where, while the handheld surgical instrument is still at or adjacent to the boundary and after the battery processor has de-energized the handheld surgical instrument, the navigation system is configured to determine that the direction of movement of the end effector is proximal or distal to the boundary and communicate a second signal to the battery processor. The system also includes where the battery processor is configured to re-energize the handheld surgical instrument based on the movement of the handheld surgical instrument being proximal to the boundary.

[0010] In yet another exemplary configuration, a surgical system for use by a medical professional to perform a procedure on a patient includes a handheld surgical instrument configured to receive an end effector, the handheld surgical instrument may include a variable speed motor configured to rotate the end effector, a trigger operable by a medical professional between a first position and a second position, a trigger sensor configured to detect the position of the trigger and output a first signal indicative of the position of the trigger, and a handpiece processor configured to control energization of the variable speed motor based at least in part on the first signal from the trigger sensor indicative of the position of the trigger. The system also includes a navigation system in communication with the processor, the navigation system configured to define a first boundary, actively determine a position of the surgical instrument relative to the first boundary, and communicate a second signal to the handpiece processor to stop the variable speed motor when the trigger sensor indicates the trigger is in the second position and the navigation system determines that the handheld surgical instrument is adjacent and / or distal to the first boundary. The system also includes a case where the handpiece processor is configured to restart the variable speed motor upon receiving a subsequent first signal from the trigger sensor indicating that a medical professional has operated the trigger to move the trigger from the second position to the first position and back to the second position while the handheld surgical instrument is still adjacent to and / or distal from the first boundary.

[0011] In yet another exemplary configuration, a surgical system for use by a medical professional in spinal or cranial surgery on a patient includes a handheld surgical instrument configured to receive an end effector, the handheld surgical instrument may include a handpiece, a variable speed motor disposed within the handpiece, a trigger operable by a medical professional to start and stop the variable speed motor, a switch operable by a medical professional between a first position and a second position to control the speed of the variable speed motor, and a processor configured to control energization of the variable speed motor. The system also includes a navigation system in communication with the processor, the navigation system configured to determine whether the switch is in the first position or the second position. This system also includes cases where the navigation system is configured to communicate a signal to the processor to control energization of the variable speed motor based on the switch being in the appropriate position and the type of end effector coupled to the handheld surgical instrument.

[0012] In yet another exemplary configuration, a surgical system for use by a medical professional in performing a surgical procedure on a patient also includes a handheld surgical tool assembly, which may include a handpiece, one of a first end effector or a second end effector, each of the first end effector and the second end effector being removably coupleable to the handpiece, a variable speed motor disposed within the handpiece, and a processor configured to control energization of the variable speed motor. The system also includes a navigation system in communication with the processor, the navigation system determining identities of the first end effector and the second end effector. The system also includes a navigation system configured to define a first boundary in a known coordinate system based at least in part on the identity of the first end effector and to define a second boundary in the known coordinate system that is different from the first boundary, the second boundary being based at least in part on the identity of the second end effector. The system also includes a configuration where, when the first end effector is identified, the navigation system is configured to communicate to the processor a first signal that controls energization of the variable speed motor based on a position of the first end effector relative to the first boundary, and when the second end effector is identified, the navigation system is configured to communicate to the processor a signal that controls energization of the variable speed motor based on a position of the second end effector relative to the second boundary.

[0013] In yet another exemplary configuration, a method for navigating a surgical instrument using a navigation system during a medical procedure on a patient. The method also includes determining a planned pose for a selected implant in a known coordinate system and creating a plurality of boundaries within the known coordinate system based on the pose of the selected implant, the plurality of boundaries including a drill-specific boundary and a driver-specific boundary. The method also includes tracking a position of the surgical instrument using the navigation system, and enabling the drill-specific boundary based on identifying the end effector as a drill instrument and enabling the driver-specific boundary based on identifying the end effector as a driver instrument. The method also includes controlling energization of a motor of the handpiece when a drill instrument is identified based on the drill-specific boundary and the position of the handpiece. The method also includes controlling energization of a motor of the handpiece when a driver instrument is identified based on the driver-specific boundary and the position of the handpiece.

[0014] In yet another exemplary configuration, a surgical system for use by a medical professional in a procedure on a patient includes a control console having a processor, a handpiece in communication with the processor of the control console, the handpiece may include an end effector and a variable speed motor that drives the end effector, and a switch operable by the medical professional between a first position and a second position to control energization of the variable speed motor. The system also includes a navigation system in communication with the processor, the navigation system configured to actively determine a position of the handpiece relative to a boundary in a known coordinate system. The system also includes a navigation system configured to communicate a first signal to the processor that temporarily de-energizes the handpiece when the navigation system determines that the position of the handpiece is at or adjacent to a boundary. The system also includes a configuration in which, when the variable speed motor is re-energized, the navigation system communicates a second signal to the processor that causes the processor to energize or de-energize the handpiece based on the movement of the handpiece being distal to the boundary.

[0015] In yet another exemplary configuration, a surgical system for use by a medical professional in a procedure on a patient includes a control console including a processor, a handpiece in communication with the processor of the control console, the handpiece may include an end effector and a variable speed motor for driving the end effector, a first switch operable by a medical professional between a first position and a second position to control energization of the variable speed motor in a forward direction, and a second switch operable by a medical professional between a first position and a second position to control energization of the variable speed motor in a reverse direction. The system also includes a navigation system in communication with the processor, the navigation system configured to actively determine a position of the handpiece relative to an alert zone defined around a critical structure on the patient. The system also includes a navigation system configured to communicate a first signal to the processor to de-energize the handpiece when the navigation system determines that the position of the handpiece enters the alert zone and the variable speed motor is in the forward direction. The system also includes a configuration in which, when the processor de-energizes the handpiece and while the handpiece remains in the alert zone, the navigation system communicates a second signal to the processor that causes the processor to prevent re-energization of the variable speed motor in the forward direction and to allow re-energization of the variable speed motor in the reverse direction.

[0016] In yet another exemplary configuration, a surgical instrument assembly for use with a navigation system configured to allow a medical professional to define alert zones on a patient to assist the medical professional in performing a procedure on the patient. The surgical instrument assembly also includes a control console that may include a control processor in communication with the navigation system. The assembly also includes a high-speed surgical burr assembly that may have a variable speed motor in communication with the control processor, the variable speed motor configured to rotate a burr. The assembly also includes a footswitch movable between a first position and a second position to energize the variable speed motor of the high-speed surgical burr assembly. The assembly also includes a footswitch sensor in communication with the control processor, the footswitch configured to detect a position of the footswitch and communicate a first signal to the control processor indicative of the position of the footswitch. The assembly also includes a tactile alert device coupled to the footswitch and in communication with the control processor, the tactile alert device positioned on the footswitch such that the tactile alert device contacts the foot of a medical professional when the medical professional depresses the footswitch to operate the high-speed surgical burr assembly. The assembly also includes a navigation system configured to actively determine the position of the burr relative to an alert zone in a known coordinate system. The assembly also includes a navigation system configured to send a second signal to the control processor when the burr enters the alert zone, the second signal activating the tactile alert device and emitting a tactile alert perceptible to the medical professional, and the processor configured to deactivate the tactile alert device upon receiving a subsequent first signal from the footswitch sensor indicating that the medical professional has moved the footswitch while the burr is still within the alert zone.

[0017] In yet another exemplary configuration, a surgical system for use by a medical professional in a procedure on a patient includes a control console including a processor, a handpiece in communication with the processor of the control console, the handpiece may include an end effector and a variable speed motor that drives the end effector, and a switch operable by a medical professional between a first position and a second position to control energization of the variable speed motor. The system also includes a navigation system in communication with the processor, the navigation system configured to actively determine a position of the handpiece relative to a boundary defined for a critical structure on the patient. The system also includes a navigation system configured to communicate a first signal to the processor in response to the end effector being adjacent to or distal from the boundary, causing the processor to adjust a torque map to which the variable speed motor of the handpiece is energized.

[0018] In yet another exemplary configuration, a surgical system configured to allow a medical professional to define alert zones relative to critical structures of a patient to assist the medical professional in performing surgery on the patient, the surgical system also comprising a navigation system. The system also comprises a control console, which may include a control processor in communication with the navigation system. The system also comprises a high-speed surgical instrument including a burr. The system also comprises a foot switch in communication with the control processor for controlling operation of the variable speed motor of the high-speed surgical instrument. The system also includes a navigation system configured to: actively determine a position of the burr relative to the alert zone; trigger an alert response when the navigation system determines that the burr has entered the alert zone; terminate the alert response based on a user input signal; and retrigger the alert response based on the burr being outside the alert zone for a predetermined period of time and then re-entering the alert zone.

[0019] These and other configurations, features, and advantages of the present disclosure will be apparent to those skilled in the art, and the present disclosure is not intended to be limited to these configurations, embodiments, features, and / or advantages.

[0020] Advantages of the present invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in conjunction with the accompanying drawings. [Brief explanation of the drawings]

[0021] [Figure 1A] FIG. 1 is a schematic diagram of a surgical system including multiple surgical tool assemblies and a surgical navigation system for tracking surgical tools associated with each of the various surgical tool assemblies. [Figure 1B] FIG. 1B is a schematic diagram illustrating an alternative configuration of the surgical system of FIG. 1A. [Figure 2] FIG. 1C is a perspective view of an exemplary layout of an operating room including at least one of the surgical instrument assemblies of FIGS. 1A and 1B and a surgical navigation system for performing a medical procedure on a patient. [Figure 3] FIG. 2 is a schematic diagram of a surgical site from the perspective of a surgeon while performing a medical procedure on a patient using at least one of the surgical tool assemblies of FIGS. 1A and 1B. [Figure 4A] FIG. 1C is a schematic diagram of a first exemplary surgical instrument in the surgical system of FIGS. 1A and 1B, the first surgical instrument oriented in a first position relative to a patient. [Figure 4B] 4B is a schematic illustration of the first surgical instrument of FIG. 4A oriented in a second position relative to the patient; [Figure 4C] 4B is a schematic illustration of the first surgical instrument of FIG. 4A oriented in a third position relative to the patient; [Figure 4D] 4B is a schematic illustration of the first surgical instrument of FIG. 4A oriented in a fourth position relative to the patient; [Figure 5A]A schematic diagram of a second exemplary surgical instrument in the surgical system of Figures 1A and 1B, the second surgical instrument being oriented in a first position relative to a patient and in a first set of predefined exemplary alert zones. [Figure 5B] FIG. 5B is a schematic illustration of the second surgical instrument of FIG. 5A, the second surgical instrument being oriented in a second position relative to the patient and within a first set of exemplary predefined alert zones. [Figure 5C] FIG. 5B is a schematic illustration of the second surgical instrument of FIG. 5A, the second surgical instrument being oriented in a third position relative to the patient and within a first set of exemplary predefined alert zones. [Figure 5D] FIG. 5B is a schematic illustration of the second surgical instrument of FIG. 5A, the second surgical instrument being oriented in a third position relative to the patient and with a second set of exemplary predefined alert zones. [Figure 5E] FIG. 5B is a schematic illustration of the second surgical instrument of FIG. 5A, the second surgical instrument being oriented in a third position relative to the patient and with a second set of exemplary predefined alert zones. [Figure 5F] 5B is a schematic diagram of the second surgical instrument of FIG. 5A, further including a battery module and a battery processor. [Figure 6] FIG. 1 is a schematic diagram of an exemplary surgical system including a navigation system and a handheld surgical instrument, the handheld surgical instrument including a battery module and multiple end effectors. [Figure 7] FIG. 1 is a schematic diagram of an exemplary surgical system including a navigation system and a high-speed burr, the high-speed burr including a control console and multiple cutting burrs. [Figure 8] 1 is a schematic diagram of an exemplary graphical user interface (GUI) of a navigation system that includes user-selectable objects related to planning and / or performing a surgical procedure. [Figure 9]FIG. 1 is a schematic diagram of an exemplary graphical user interface (GUI) of a navigation system that displays an image of the proposed placement of a surgical implant and user-selectable objects related to the depth of the implant. [Figure 10] FIG. 1 is a schematic diagram of an exemplary graphical user interface (GUI) of a navigation system that displays an image of the planned placement of surgical implants and user-selectable objects related to settings for various surgical instruments to be used in performing a surgical procedure. [Figure 11A] 1 is a schematic diagram of an exemplary graphical user interface (GUI) of a navigation system displaying user-selectable objects related to volumes defining alert zones. [Figure 11B] 11B is a schematic diagram of the example graphical user interface (GUI) of FIG. 11A illustrating the volume defining the alert zone from different perspectives. [Figure 11C] 11B is a schematic diagram of the example graphical user interface (GUI) of FIG. 11A illustrating the volume defining the alert zone from different perspectives. [Figure 12A] FIG. 1 is a schematic diagram of an exemplary graphical user interface (GUI) of a navigation system displaying user-selectable objects related to boundaries defining an alert zone. [Figure 12B] 12B is a schematic diagram of the example graphical user interface (GUI) of FIG. 12A illustrating the boundaries that define the alert zone from different perspectives. [Figure 12C] 12B is a schematic diagram of the example graphical user interface (GUI) of FIG. 12A illustrating the boundaries that define the alert zone from different perspectives. [Figure 13A]1 is a schematic diagram of an exemplary graphical user interface (GUI) of a navigation system illustrating a sagittal view of patient space during placement of a surgical implant. [Figure 13B] 13B is a schematic diagram of the exemplary graphical user interface (GUI) of FIG. 13A illustrating axial imaging of patient space during placement of a surgical implant. DETAILED DESCRIPTION OF THE INVENTION

[0022] It is of utmost importance to accurately track surgical instruments during surgery to follow the planned surgical path and / or avoid critical anatomical structures, and it is equally important to provide feedback and / or notify the operating medical professional if the surgical instrument deviates from the surgical path and / or is at risk of colliding with critical anatomical structures.

[0023] 1A and 1B illustrate an exemplary surgical system 10. The system may include a surgical navigation system 100 that tracks one or more surgical tool assemblies 200, 300, 400 having surgical tools 220, 320, 420 to assist a medical professional, such as a surgeon, in performing a medical procedure.

[0024] The surgical navigation system 100 may include a navigation interface. The navigation interface may include one or more display units 120, such as one or more graphical user interfaces (GUIs) 150, and one or more user inputs 130. The display unit 120 of the surgical navigation system 100 may be configured to display various prompts or data entry boxes. For example, the display unit 120 may be configured to display text boxes or prompts that allow the surgeon to manually enter or select the type of surgical procedure to be performed. Additionally, the display unit 120 may be configured to display patient data, such as pre-operative images or scans. As described above, pre-operative images may be based on MRI scans, X-ray scans, or computed tomography (CT) scans of the patient's anatomy. The pre-operative images may be uploaded to the surgical navigation system 100 and then displayed on the display unit 120. The display unit 120 may further be configured to display a surgical plan for a medical procedure overlaid on the patient's data or images.

[0025] The surgical plan may include a surgical path for performing a medical procedure or a planned trajectory or direction for a medical instrument during a medical procedure. The surgical plan may also include overlaying the position and / or direction of an implant or medical device to be inserted during a medical procedure onto patient data or an image. It is also contemplated that the surgical navigation system 100 may include a display unit 120 configured to display and / or project a holographic image of the surgical path for performing a medical procedure or the planned trajectory or direction for a medical instrument during a medical procedure. This may include projecting the surgical path onto a patient or other surface in an operating room. This may further include projecting the surgical path onto a head unit worn by the surgeon, such as a head unit lens, a shield, or glasses. An exemplary configuration of the surgical navigation system 100 including a display unit worn by the surgeon for displaying the target trajectory and / or target location is disclosed in International Patent Application No. PCT / IB2018 / 053130, the entire disclosure of which is incorporated herein by reference.

[0026] The user input 130 and / or the graphical user interface (GUI) 150 can be configured to allow the surgeon to input or enter patient data or modify the surgical plan. The patient data can include patient images, such as preoperative images of the patient's anatomy. Such images can be based on MRI scans, X-ray scans, or computed tomography (CT) scans of the patient's anatomy. The patient data can also include additional information related to the type of medical procedure being performed, the patient's anatomy, the patient's particular medical condition, and / or the operational settings of the surgical navigation settings. For example, when performing spinal surgery, the surgeon can input information related to the particular vertebra on which the medical procedure is being performed via the user input 130 and / or the graphical user interface (GUI) 150. The surgeon can also input various anatomical dimensions for the vertebra and / or the size and shape of the medical device or implant to be inserted during the medical procedure. Additionally, the user input 130 and / or the graphical user interface (GUI) 150 can be configured to allow the surgeon to select, edit, or manipulate patient data. For example, the surgeon may identify and / or select anatomical features from the patient data, which may include selecting a surgical site, such as a vertebra and / or a particular location on a vertebra, where a medical procedure will be performed.

[0027] Additionally, the surgeon may be able to identify important anatomical features, such as anatomical features that the surgeon may wish to target or avoid during the medical procedure. For example, the surgeon may use user input 130 and / or graphical user interface (GUI) 150 to select cortical walls, nerves, blood vessels, or similar important anatomical structures that the surgeon wishes to avoid and establish zones surrounding these anatomical structures. Additionally, the surgeon may use user input 130 and / or graphical user interface (GUI) 150 to select and / or input target locations, trajectories, depths, or similar features of a surgical path to help guide the surgeon in performing the medical procedure.

[0028] The system may be configured to utilize segmentation to assist in identifying zones and / or boundaries of interest, which may be done automatically, semi-automatically, or manually.

[0029] In one example of manual segmentation, the surgeon can further define geometric primitives that define the region of interest using user input 130 and / or a graphical user interface (GUI) 150. A method for defining geometric primitives for the segmentation and visualization of body cavities or orifices can include the following steps: manually pre-segmenting the anatomical structures within the pre-segmented geometric primitives by defining closed geometric primitives within a three-dimensional patient image and generating an initial envelope; analyzing anatomical structures within the pre-segmented geometric primitives; adjusting the envelopes using the results of the analysis; and visualizing the envelopes. Adjusting the visualized envelopes can be based on the analyzed anatomical structures using calculated voxel associations, and adjusting the visualized cell envelopes can be achieved by calculating a surface mesh of voxels that are fully and / or partially associated with the cells. Adjusting the visualized envelopes can also be achieved by optimizing the type, orientation, position, and / or size of the closed geometric primitives. Exemplary methods and systems for defining geometric primitives and guiding surgical instruments are disclosed in U.S. patent application Ser. No. 15 / 300,414 and U.S. patent application Ser. No. 15 / 582,637, both of which are incorporated herein by reference in their entireties.

[0030] Additionally, the user input 130 and / or the graphical user interface (GUI) 150 can be configured to input a surgical plan. This may include selecting the surgical instruments to be used, the devices and / or implants to be inserted, and specifying the location and / or orientation (i.e., posture) at which the devices or implants will be placed within the patient. The user input 130 and / or the graphical user interface (GUI) 150 may also allow the surgeon to select parameters of the implants to be inserted, such as the length and / or diameter of the screws to be inserted.

[0031] Additionally, the surgical navigation system 100 may also include a navigation processor 140. The navigation processor 140 may be located in a personal or laptop computer. The navigation processor 140 may be in communication with the user input 130, the display unit 120, a central processing unit (CPU), and / or other processors, memory (not shown), and storage (not shown). The navigation processor 140 may further include software and / or operating instructions for implementing various routines and / or methods associated with the operation of the surgical navigation system 100 and disclosed herein. The software and / or operating instructions may include a planning system configured to determine the precise position and / or angular alignment of the implant relative to the patient 20. The navigation processor 140 may be in direct or indirect, wired, or wireless communication with the surgical instrument assemblies 200, 300, 400.

[0032] The navigation system may also include software used by the navigation processor 140 to control the operation of the surgical instruments 220, 320, 420. The software may include a boundary generator and / or an alert zone generator. The boundary generator can be implemented in the navigation processor 140, the instrument processor 215, 315, 415, and / or other components, such as a separate processor or controller. Exemplary systems and methods for boundary generation can be found in U.S. Patent Publication No. 2004 / 0034283, the entire contents of which are incorporated herein by reference. The boundary generator may also be part of a separate system remotely operated from the surgical instruments 220, 320, 420. The boundary generator is a software program or module that generates one or more virtual boundaries to restrict the movement and / or operation of the surgical instruments 220, 320, 420. In some examples, the boundary generator provides virtual boundaries that define a virtual drill and / or driver guide (e.g., a virtual implant planning guide). Additionally, virtual boundaries or alert zones can be provided to control the movement of the surgical instruments 220, 320, 420 relative to critical anatomical features, target depths, and / or target locations that the surgeon wishes to avoid. Virtual boundaries can be one-dimensional (1D), two-dimensional (2D), or three-dimensional (3D) and can have other shapes, including points, lines, axes, loci, planes (infinite planes or planar segments bounded by anatomical structures or other boundaries), volumes, or complex geometric shapes. Virtual boundaries can be represented by pixels, point clouds, voxels, triangular meshes, other 2D or 3D models, combinations thereof, or the like. U.S. Patent Publication No. 2018 / 0333207 and U.S. Patent No. 8,898,043 are incorporated herein by reference, and any of these features can be used to assist in the planning or execution of a surgical procedure. Multiple boundaries can be used to define zones.

[0033] The virtual boundary can be used in a variety of ways. For example, the navigation processor 140 can control certain operations / functions of the surgical instrument 220, 320, 420 based on the relationship (e.g., spatial, velocity, etc.) of the surgical instrument 220, 320, 420 to the boundary. Other uses of the boundary are also contemplated.

[0034] The boundary for ensuring that the instrument is placed at the desired depth can be defined as a virtual planar boundary, a virtual volume boundary, or some other form of virtual boundary. A virtual boundary is sometimes referred to as a virtual object. The virtual boundary can be defined with respect to an anatomical model, such as a 3D bone model. That is, points, lines, axes, trajectories, planes, volumes, etc., associated with the virtual boundary are defined in a coordinate system that is fixed relative to the coordinate system of the anatomical model, such that when the anatomical model is tracked (e.g., via tracking of registered associated anatomical structures), the virtual boundary can also be tracked.

[0035] The anatomical model is registered to the first patient tracking device so that the virtual boundary is associated with the anatomical model and associated coordinate system. The virtual boundary may be implant-specific, e.g., defined based on the size, shape, volume, etc. of the implant, and / or patient-specific, e.g., defined based on the patient's anatomy. The virtual boundary may be a boundary created pre-operatively, intra-operatively, or a combination thereof. That is, the virtual boundary may be defined before the start of the surgical procedure, during the surgical procedure (including during tissue removal), or a combination thereof. The virtual boundary may be provided in many ways, such as created by the navigation processor 140 or received from another source / system. The virtual boundary may be stored in memory for retrieval and / or updating.

[0036] It is further contemplated that in some cases, the virtual boundary may have multiple planar boundaries that can be used to define multiple target depths (e.g., three target depths) for different instruments to be used in a single procedure. For example, as shown in FIG. 5D , a first virtual boundary representing the target depth for a drill to drill a hole, a second virtual boundary representing the target depth for a tap (puncture), and a third virtual boundary representing the target depth for a driver to insert a screw are detailed below. These multiple virtual boundaries can be enabled one at a time by navigation processor 140 to constrain cutting to one plane at a time. Navigation processor 140 tracks the state of surgical instruments 220, 320, 420 relative to the virtual boundaries.

[0037] The surgical navigation system 100 may also include a tracking unit 110 comprising one or more sensors 115. The sensors may include cameras, such as CCD cameras, CMOS cameras, and / or optical imaging cameras, magnetic sensors, radio frequency sensors, or any other sensors adapted to detect and / or sense the position of the tracking devices 230, 330, 430 of the surgical tool assemblies 200, 300, 400. A description of a suitable tracking unit and various localizers it may utilize is provided in U.S. Patent Publication No. 2017 / 0333137, the entire contents of which are incorporated herein by reference.

[0038] 1A and 1B, various exemplary surgical instrument assemblies 200, 300, 400 are illustrated in communication with the surgical navigation system 100. Each of the various exemplary surgical instrument assemblies is described in detail below. The surgical instrument assemblies 200, 300, 400 can be configured for wired and / or wireless communication with the surgical navigation system 100. Additionally, each of the surgical instrument assemblies 200, 300, 400 can include a number of similar components that can perform similar functions and / or operations. Similar components among each of the surgical instrument assemblies 200, 300, 400 are identified by the same two-digit number with a leading 2, 3, or 4 to indicate the associated surgical instrument assembly 200, 300, 400. For example, each of the surgical instrument assemblies 200, 300, 400 can include surgical instruments 220, 320, and 420, respectively.

[0039] The surgical system 10 may include a first surgical tool assembly 200 in communication with the navigation system 100. For example, the first surgical tool assembly 200 may be configured as a first surgical tool 220, such as a surgical drill or driver, that includes a handpiece 225. The handpiece 225 may include a housing 210 configured to house the components of the first surgical tool 220. The handpiece 225 may be shaped to define a handle or grip for grasping by a surgeon during the performance of a medical procedure. A suitable handpiece is described in U.S. Patent No. 5,747,953, the entire contents of which are incorporated herein by reference.

[0040] The first surgical instrument 220 may further include a first instrument processor 215 and a motor 245. The first instrument processor 215 and the motor 245 may each be disposed within a handpiece 225 of the first surgical instrument 220. The first instrument processor 215 and the motor 245 may be in communication with each other, and the first instrument processor 215 may be configured to control the operation of the motor 245 and, therefore, the operation of the first surgical instrument 220. For example, the first surgical instrument 220 may include an end effector 240, such as a drill bit for drilling holes or a driver for inserting screws. The end effector 240 may be coupled to the handpiece 225 of the first surgical instrument 220 such that the motor 245 is operably coupled to the end effector 240. For example, the motor 245 may be configured to rotate the drill bit 240 to drill holes and / or remove tissue. The first instrument processor 215 can be in communication with the motor 245 and can be configured to control the operation of the motor 245 and, therefore, the drill bit 240. Additionally, the first instrument processor 215 can be in communication with the navigation processor 140 and can be configured to exchange data related to the position and / or orientation of the first surgical instrument 220, as well as data related to the operation of the first surgical instrument 220. For example, the first instrument processor 215 and the navigation processor 140 can be configured to communicate data related to the operation of the first surgical instrument 220 with each other based on the position and / or orientation of the first surgical instrument 220 detected by the surgical navigation system 100.

[0041] The first surgical tool assembly 200 may also include a power source 260. The power source 260 may be removably coupled to the handpiece 225 of the surgical drill 220. For example, the power source 260 may include a removable battery pack. It is contemplated that the power source 260 may be formed as part of or disposed within the handpiece 225 of the first surgical tool 220. The power source 260 may be in electrical communication with the first tool processor 215 and / or the motor 245 and configured to selectively power the motor 245 to rotate the end effector 240. Alternatively, the power source may be a surgical console that provides power to the first surgical tool via a cord.

[0042] When the power source is in the form of a removable battery pack, the power source 260 can also include a processor 265. The processor 265 can communicate within the first instrument processor 215 via power and / or data signals. The processor 265 and the first instrument processor 215 can be configured to communicate with each other to control the operation of the motor 245 and, therefore, the first surgical instrument 220. For example, the processor 265 within the power source 260 can be configured to determine when the power source 260 falls below a threshold charge level that may prevent the power source 260 from continuing to operate the motor 245 at a minimum threshold for perforating or cutting tissue. The processor 265 can be configured to completely cut off power to the first instrument processor 215 and / or the motor 245 to prevent operation of the end effector 240 until the power source 260 has a sufficient charge level to operate the motor 245 at a speed above the minimum threshold for perforating or cutting tissue. The processor 265 within the power source 260 can also wirelessly communicate with the navigation processor 140. The power source 260 may include a transceiver configured to send and receive signals between the power source 260 and the surgical navigation system 100 and / or the instrument processor 215.

[0043] The processor 265 and the navigation processor 140 can be configured to communicate data to each other related to the operation of the first surgical instrument 220 based on the position and / or orientation of the first surgical instrument 220 detected by the surgical navigation system 100. For example, the navigation system 100 can be configured to communicate data to the processor 265 including instructions for the processor 265 to cease supplying energy to the first instrument processor 215 and / or the motor 245 based on the position and / or orientation of the first surgical instrument 220 detected by the surgical navigation system 100. Additionally, the navigation system 100 can be configured to communicate data to the processor 265 including instructions for the processor 265 to continue and / or resume supplying energy to the first instrument processor 215 and / or the motor 245 based on the position and / or orientation of the first surgical instrument 220 detected by the surgical navigation system 100.

[0044] The first surgical tool assembly 200 may also include a switch 250, such as a trigger, button, or lever, operably coupled to the first tool processor 215. The switch 250 may be configured to be operable by a medical professional to control the application of energy to the variable speed motor 245. For example, the switch 250 may be operable between a first position, in which the switch 250 is de-energized, and a second position, in which the switch 250 is energized. The first surgical tool assembly 200 may also include a switch sensor configured to detect the position of the switch 250 and, based on the user's manipulation of the switch 250 to control the operation of the first surgical tool 220, generate and / or communicate a signal indicative of the position of the switch 250 to the first tool processor 215. For example, the switch 250 may include a first position, a second position, and multiple intermediate positions between the first and second positions. The first position may be configured as an off position such that when the first instrument processor 215 receives a signal that the switch sensor detects that the switch 250 is in the first position, the first instrument processor 215 blocks the flow of energy from the power source 260 to the motor 245, preventing operation of the first surgical instrument 220. Alternatively, the first instrument processor 215 may be configured such that when the first instrument processor 215 receives a signal that the switch sensor detects that the switch 250 is in the second position, the first instrument processor 215 allows a maximum flow of energy from the power source 260 to the motor 245, thereby allowing the first surgical instrument 220 to operate at a maximum drilling or cutting speed. When the first instrument processor 215 receives a signal that the switch sensor has detected that the switch 250 is in one of the intermediate positions, the first instrument processor 215 can be configured to allow a level of energy corresponding to the position of the switch 250 between the first and second positions to flow from the power source 260 to the motor 245, thereby allowing the first surgical instrument 220 to operate at an intermediate level of drilling or cutting speed.For example, when the first instrument processor 215 receives a signal that the switch sensor detects that the switch 250 is positioned halfway (50%) between the first and second positions, the first instrument processor 215 can be configured to allow a level of energy to flow from the power source 260 to the motor 245 that enables the first surgical instrument 220 to operate at 50% of its maximum drilling or driving speed. Alternatively, the first instrument processor 215 can be configured to allow a maximum flow of energy to flow from the power source 260 to the motor 245 whenever the switch 250 is in a position other than the first position, thereby enabling the first surgical instrument 220 to operate at its maximum drilling or cutting speed when the switch 250 is in either the second or intermediate position. An exemplary switch sensor can be found in U.S. Pat. No. 9,295,476, the entire contents of which are incorporated herein by reference.

[0045] The first surgical tool assembly 200 can also include a first alert device 255. The first alert device 255 can include an audible, tactile, and / or visually perceptible device. The first alert device 255 can be configured to communicate with the first tool processor 215 or a processor of the power source 260. The first tool processor 215 or other processor can be configured to send a signal that activates the first alert device 255 to provide a warning or notification based on a preprogrammed condition or setting.

[0046] For example, as described above, the surgeon can use user input 130 to input predetermined conditions and / or settings into surgical navigation system 100, such as to select cortical walls, nerves, blood vessels, or similar critical anatomical structures that the surgeon wishes to avoid and to establish regions or zones surrounding these anatomical structures. Additionally, the surgeon can use user input 130 to select and / or input target positions (location(s)), target trajectories in one or more degrees of freedom, or no-cut zones, or similarly shaped portions of a surgical path to help guide the surgeon in performing a medical procedure. Based on data provided by navigation processor 140, first instrument processor 215 can be configured to send a signal to activate first alert device 255 when end effector 240 of first surgical instrument 220 enters one of the regions and / or zones defined by the surgeon. The first instrument processor 215 or other processor can also be configured to send a signal to activate the first alert device 255 when the end effector 240 of the first surgical instrument 220 deviates from its trajectory and / or when the end effector 240 reaches a target position based on data provided by the navigation processor 140.

[0047] In an exemplary configuration, the first alert device 255 can include a vibration device that contacts the surgeon and is configured to vibrate to notify or warn the surgeon of a particular condition. In an exemplary configuration, as shown in FIGS. 1A and 1B , the first alert device 255 can include a vibration device coupled to a switch 250 that controls the operation of the first surgical instrument 220. The first alert device 255 can be configured to vibrate upon the occurrence of a predetermined condition. Because the surgeon is constantly in contact with the switch 250 when the first surgical instrument 220 is activated, the surgeon will feel the first alert device 255 vibrate and be notified of the occurrence of the predetermined condition. The first alert device 255 can be configured to generate vibrations in a particular pattern or at a particular interval upon the occurrence of a predetermined condition. Alternatively, the first alert device 255 can be configured to generate a first vibration in a particular pattern or at a particular interval upon the occurrence of a first condition, and a second vibration in a different pattern or at a different interval upon the occurrence of a second condition.

[0048] The first alert device 255 can also be configured as an audible device, such as a speaker configured to provide an audible alert to the surgeon upon the occurrence of a predetermined condition. For example, the first alert device 255 can include a speaker configured to generate a particular sound upon the occurrence of a predetermined condition. Alternatively, the first alert device 255 can include a speaker configured to generate a sound in a particular pattern or at particular intervals upon the occurrence of a predetermined condition. The speaker can be included as part of a surgical navigation system.

[0049] Alternatively, the first alert device 255 can be configured as a visually perceptible device or indicator, such as a visual display configured to provide a visual alert to the surgeon upon the occurrence of a predetermined condition. For example, the first alert device 255 can include a light configured to flash upon the occurrence of a predetermined condition. Alternatively, the first alert device 255 can include a plurality of multi-colored lights configured to illuminate and / or flash in a predetermined color or pattern upon the occurrence of a predetermined condition. If the first alert device is a display, the display can be configured to generate a visual cue indicative of the alert condition. The navigation display 120 can be used as a display for the first alert device 255, such that the navigation display 120 is configured to provide a visual cue to alert the surgeon. For example, the navigation display 120 can be configured to display a prompt or window when the first alert device 255 is triggered to provide a notification to the surgeon. Alternatively, the navigation display 120 can be configured to flash and / or change color when the first alert device is triggered. One of the many advantages of using the navigation display 120 as the display for the first alert device 255 is that the surgeon will likely already be looking at the navigation display 120 regularly during surgery, and therefore, if the navigation display 120 is configured to display notifications provided by the first alert device 255, the surgeon will be more likely to receive visual notifications quickly.

[0050] The removable power supply 260 may further include a first alert device in certain configurations, for example, the removable power supply 260 may include a vibration motor or speaker that responds to signals generated by the navigation processor.

[0051] It is further contemplated that the first alert device 255 can include a combination of audible, tactile, and / or visually perceptible devices. For example, the first alert device 255 can be configured as a combination of an audible device and a tactile device, where the tactile device can be configured to vibrate to provide a first alert and the audible device can be configured to emit a noise to provide a second alert. The first and second alerts can indicate the occurrence of the same predetermined condition, or the first and second alerts can indicate the occurrence of different predetermined conditions. For example, the first alert can be based on the first surgical instrument 220 deviating from a target trajectory and the second alert can be based on the end effector 240 reaching a target position.

[0052] While the first alert device 255 is illustrated as being coupled to or proximate to the switch 250 of the first surgical instrument assembly 200, it is contemplated that the first alert device 255 may be coupled to and / or positioned in other locations. For example, if the first alert device 255 includes a tactile device, the first alert device 255 can be configured as a vibrating member removably attached to the surgeon. The first alert device 255 can be configured as a wearable device, such as a bracelet worn on the surgeon's wrist or arm, so that the surgeon can feel the first alert device 255 vibrate upon the occurrence of a predetermined condition. Alternatively, if the first alert device 255 includes an audible device, the first alert device 255 can be configured as a speaker removably attached to the surgeon. The first alert device 255 can be configured as a Bluetooth-enabled speaker or earpiece to be worn on the surgeon's head or placed in the surgeon's ear so that the surgeon can hear a noise made by the first alert device 255 when a predetermined condition occurs.

[0053] While not required, locating the first alert device 255 remotely from the first surgical instrument 220 has many advantages. For example, one advantage of locating the first alert device 255 remotely from the first surgical instrument 220 is that it reduces the size of the first surgical instrument 220, allowing the first surgical instrument 220 to fit into a smaller space. A smaller first surgical instrument 220 also reduces the obstruction of the surgeon's view of the surgical site. Another advantage of locating the first alert device 255 remotely from the first surgical instrument 220, particularly in the case of a tactile device, is that the first alert device 255 does not vibrate or affect the movement of the first surgical instrument 220 while still providing an alert or notification to the surgeon. During highly technical procedures, an alert that vibrates the first surgical instrument 220 increases the risk that the surgeon will be startled by the first alert device 255 and / or that the vibrations will cause undesirable movement of the first surgical instrument 220, causing the surgeon to move the first surgical instrument 220 to an undesired position.

[0054] The first surgical tool assembly 200 may also include a tracking device 230. The tracking device 230 may be coupled to the handpiece 225 of the first surgical tool 220. The tracking device 230 may include multiple markers 235 identifiable by the tracking unit 110 of the surgical navigation system 100. The markers 235 may include passive tracking elements (e.g., reflectors) for transmitting optical signals to the sensor(s) 115 (e.g., reflecting light emitted from the tracking unit 110). In other configurations, the markers 235 may be configured as active tracking markers. It is further contemplated that the markers 235 may have a combination of active and passive configurations. The markers 235 may be positioned at a defined or known position and orientation relative to the other markers 235 to enable the surgical navigation system 100 to determine the position and orientation (pose) of the surgical tool 220. For example, the marker 235 can be aligned with the first surgical instrument 220 to enable the surgical navigation system 100 to determine the position and / or orientation of the end effector 240 or cutting portion of the first surgical instrument 220 within a defined space, such as a surgical field. In one exemplary configuration, the surgical navigation system 100 can be configured to determine the position and / or orientation of the cutting portion of the end effector 240 or second surgical instrument 220, or the position and / or orientation relative to a target trajectory and / or target location of a planned surgical path. In another exemplary configuration, the surgical navigation system 100 can be further configured to determine the position and / or orientation of the cutting portion of the end effector 240 or second surgical instrument 220, or the position and / or orientation relative to important anatomical structures within the patient's body, as well as the position and / or orientation relative to user-defined boundaries, zones, and / or regions.

[0055] Alternatively, the surgical system 10 can include a second surgical instrument assembly 300 to be used with the navigation system 100. For example, the second surgical instrument assembly 300 may include a second surgical instrument 320, such as a high-speed surgical burr or an ultrasonic surgical handpiece, including a handpiece 325. The handpiece 325 is coupleable to a console 310 configured to control the operation of various components of the second surgical instrument 320. The handpiece 325 may be shaped to define a handle or grip portion that a surgeon grasps while performing a medical procedure. Exemplary second surgical instruments that connect to a console can be found in U.S. Pat. No. 10,016,209 and U.S. Patent Publication No. 20190117322, each of which is incorporated herein by reference in its entirety.

[0056] The second surgical instrument 320 can further include a second instrument processor 315 and a motor 345. The second instrument processor 315 can be located within the console 310 of the second surgical instrument assembly 300. The motor 345 can be located within the handpiece 325 of the second surgical instrument 320. The second instrument processor 315 and the motor 345 can be in communication with each other, and the second instrument processor 315 can be configured to control the operation of the motor 345 and, therefore, the operation of the second surgical instrument 320. For example, the second surgical instrument 320 can be coupled to the console with a cord connecting the second instrument processor 315 and the motor 345, allowing communication between the second instrument processor 315 and the motor 345 to control the operation of the motor. Additionally, the second instrument processor 315 can include an end effector 340, such as a high-speed cutting burr or an ultrasonic tip. The end effector 340 can be coupled to the handpiece 325 of the second surgical instrument 320 such that the motor 345 can be operatively coupled to the end effector 340. For example, the motor 345 can be configured to drive the high-speed cutting burr 340 to abrade and / or remove biological tissue from the surgical site or to vibrate the ultrasonic tip. The second instrument processor 315 can be in communication with the motor 345 and configured to control the operation of the motor 345 and, therefore, the high-speed cutting burr 340. Furthermore, the second instrument processor 315 can be in communication with the navigation processor 140 and configured to exchange data related to the position and / or orientation of the second surgical instrument 320, as well as data related to the operation of the second surgical instrument 320. For example, the second instrument processor 315 and the navigation processor 140 can be configured to mutually communicate data related to the operation of the second surgical instrument 320 based on the position and / or orientation of the second surgical instrument 320 detected by the surgical navigation system 100. It is also contemplated that additional surgical instruments may be coupled to the console and / or in communication with a second instrument processor 315 located within the console 310.

[0057] The second surgical tool assembly 300 may also include a power source (not shown). The power source is coupled to the console 310 of the second surgical tool assembly 300 and is configurable to provide energy to the motor 345 of the second surgical tool 320 to drive the end effector 340. It is further contemplated that the console 310 may be provided with a cord configured to be plugged into an outlet connected to an electrical grid to provide energy to the second surgical tool assembly 300. The power source is in electrical communication with the second tool processor 315 and / or the motor 345 and is configurable to selectively power the motor 345 to drive the end effector 340.

[0058] The second surgical tool assembly 300 may also include a switch 350, such as a footswitch, trigger, or button, operably coupled to the second tool processor 315. The switch 350 may be configured to generate and / or communicate a signal to the second tool processor 315 based on a user input that controls operation of the second surgical tool 320. For example, the switch 350 may include a first position, a second position, and multiple intermediate positions between the first and second positions. The first position may be configured as an off position such that, when the first tool processor 315 detects that the switch 350 is in the first position, the first tool processor 315 blocks the flow of energy from the power source to the motor 345, preventing operation of the second surgical tool 320. Alternatively, the second instrument processor 315 can be configured such that when the first instrument processor 315 detects that the switch 350 is in the second position, it allows a maximum flow of energy from the power source to the motor 345, thereby allowing the second surgical instrument 320 to operate at a maximum speed or displacement, such as a maximum cutting or grinding speed, or a maximum vibration speed or vibration amplitude. The second instrument processor 315 can be configured such that when the second instrument processor 315 detects that the switch 350 is in one of the intermediate positions, it allows a level of energy to flow from the power source to the motor 345 corresponding to the position of the switch 350 between the first and second positions, thereby allowing the second surgical instrument 320 to operate at an intermediate level of cutting or grinding speed. For example, when the second tool processor 315 detects that the switch 350 is positioned halfway (50%) between the first and second positions, the second tool processor 315 can be configured to allow a level of energy to flow from the power source to the motor 345 that enables the second surgical tool 320 to operate at 50% of its maximum cutting or grinding speed. Alternatively, the second tool processor 315 can be configured to allow a maximum flow of energy from the power source to the motor 345 whenever the switch 350 is in a position other than the first position, thereby enabling the second surgical tool 320 to operate at its maximum cutting or grinding speed when the switch 350 is in the second position or any of its intermediate positions.

[0059] Although not shown, it is contemplated that multiple surgical instruments 320 may be coupled to the console 310 and controllable by a foot switch. A switch 350, such as a foot switch, may be configured to control each of the multiple surgical instruments. For example, a single foot switch may include multiple buttons, with each button assigned to one of the multiple surgical instruments. An exemplary surgical system including a switch connected to a console controlling multiple surgical instruments is disclosed in U.S. Patent Application No. 15 / 450,477, which is incorporated herein by reference in its entirety.

[0060] The second surgical instrument assembly 300 can also include a second alert device 355. The second alert device 355 can include an audible, tactile, and / or visually perceptible device. The second alert device 355 can be configured to communicate with the second instrument processor 315 or directly with the navigation processor. The second instrument processor 315 or the navigation processor can be configured to send a signal that activates the second alert device 355 to provide a warning or notification based on a preprogrammed condition or setting.

[0061] For example, as described above, the surgeon can use the user input 130 to select cortical boundaries, nerves, blood vessels, or similar critical anatomical structures that the surgeon wishes to avoid and input predetermined conditions and / or settings into the surgical navigation system 100, such as for establishing boundaries or zones surrounding these anatomical structures. Additionally, the surgeon can use the user input 130 to select and / or input target locations, target trajectories, or similar features to help guide the surgeon in performing a medical procedure. Based on data provided by the navigation processor 140, the second instrument processor 315 can be configured to transmit a signal that activates the second alert device 355 when the end effector 340 of the second surgical instrument 320 surrounds the anatomical structures and enters one of the regions and / or zones defined by the surgeon. For example, the surgeon can use the user input 130 of the surgical navigation system 100 to define boundaries or zones for an anatomical model. This can include identifying critical anatomical features, such as specific walls of vertebral bodies, central foramina, nerves, or blood vessels, and assigning them to zones. As described above, the navigation system 100 can include a boundary generator for generating virtual boundaries within the patient that relate to significant anatomical features. As part of generating such boundaries, the navigation system 100 can be configured to recognize and / or define virtual boundaries based on a segmentation algorithm. Once the navigation system 100 generates one or more virtual boundaries, the navigation system 140 can be further configured to allow the surgeon to select a depth or distance. Once the surgeon selects a depth, the navigation system 100 can be configured to project a second virtual boundary at the selected depth or distance from the original virtual boundary. The region and / or volume defined between the original and second virtual boundaries can define at least a portion of a zone. Exemplary systems and / or methods for segmentation can be found in U.S. Patent Publication No. 2017 / 0061242, the entire contents of which are incorporated herein by reference.

[0062] This may include identifying additional zones that include regions or areas surrounding the critical anatomical feature, such as defining a second zone that surrounds the critical anatomical feature but separates it from the boundary of the critical anatomical feature. This may also include defining additional subsequent zones, such as a third zone that surrounds the second zone and is separated from the boundary of the critical anatomical feature by a distance greater than the distance the second zone is separated from the critical anatomical feature. In this exemplary configuration, the end effector 340 is likely to contact the outermost alert zone first, thereby triggering the second alert device 355 to generate a first alert. The end effector 340 may then contact the alert zone next closest to the critical anatomical feature and trigger the alert device 355 to generate a second alert. The first and second alerts are configured to notify the surgeon that the end effector 340 has entered the respective alert zones assigned to the first and second alerts. The surgical navigation system 100 can be configured to allow the surgeon to define alert zone(s) or region(s) as needed for a particular procedure. The alert zone(s) can be configured as a boundary or region surrounding a critical anatomical structure. For example, the alert zone(s) can include a region or layer surrounding the critical anatomical structure. The surgeon can define the thickness of the alert zone in the surgical navigation system 100. For example, a second alert zone adjacent to the critical anatomical structure can be defined as a 2-mm thick region surrounding the critical anatomical structure. The thickness can vary based on the type of surgery and / or surgeon preference to ensure contact with the critical anatomical structure is avoided. The surgeon can define a subsequent alert zone adjacent to the second alert zone on the opposite side of the critical anatomical structure, such that the subsequent alert zone is further away from the critical anatomical structure than the second alert zone.

[0063] The surgeon can define a subsequent alert zone as a 5 mm thick area surrounding the outermost perimeter of the second alert zone. The thickness can be adjusted using an input device based on the type of surgery and / or surgeon preference.

[0064] It will be appreciated that such alert zones may be automatically generated based on segmentation data from a patient scan.

[0065] The second instrument processor 315 can also be configured, based on data provided by the navigation processor 140, to send a signal to activate a second alert device 355 when the end effector 340 of the second surgical instrument 320 deviates from the trajectory and / or when the end effector 340 reaches a target location / zone / boundary. For example, the second alert device 355 can be activated to generate at least one of an audible, tactile, or visually perceptible alert based on the surgical navigation system 100 identifying that the end effector 340 and / or the second surgical instrument 320 is not properly aligned with a target trajectory established as part of a panned surgical path. In this exemplary configuration, the second alert device 355 can generate a tactile alert, such as vibrating the switch 350 or detachable power source, to notify the surgeon that the end effector 340 is not properly aligned with the target trajectory. Once the end effector 340 is properly aligned with the target trajectory, the second alert device 355 can be deactivated. The second alert device 355 can similarly be configured to activate to generate at least one of an audible, tactile, or visually perceptible alert based on the surgical navigation system 100 identifying that the end effector 340 and / or second surgical instrument 320 have reached a target location determined by the surgeon. For example, the second alert device 355 can generate a tactile alert, such as a vibration of the switch 350, to notify the surgeon that the end effector 340 has reached a target location / zone, such as a suitable depth or location relative to a critical anatomical boundary. It is also contemplated that the control console can be configured to stop the motor, and therefore the end effector 340, once the end effector 340 has reached the target location, so that the end effector 340 does not exceed the target location / zone.

[0066] In an exemplary configuration, the second alert device 355 can include a vibration device that contacts the surgeon and is configured to vibrate to notify or warn the surgeon of a particular condition. In an exemplary configuration, as shown in FIGS. 1A and 1B , the second alert device 355 can include a vibration device coupled to a switch 350, such as a footswitch, that controls operation of the second surgical instrument 320. The second alert device 355 can be configured to vibrate upon the occurrence of a predetermined condition. For example, the second alert device can include a vibration device coupled to and / or in communication with the footswitch 350. In this configuration, the second alert device 355 can be configured to vibrate the footswitch 350 to notify the surgeon of the occurrence of a predetermined condition, such as the end effector 340 of the second surgical instrument 320 approaching and / or entering one of the defined alert zones. Because the surgeon is constantly in contact with the switch 350 when actuating the second surgical instrument 320, the surgeon will feel the second alert device 355 vibrate, alerting them to the occurrence of a predetermined condition without affecting their grip on the handheld surgical instrument. The second alert device 355 can be configured to generate vibrations in a particular pattern or at a particular interval upon the occurrence of a predetermined condition. Alternatively, the second alert device 355 can be configured to generate a first vibration in a particular pattern or at a particular interval upon the occurrence of a first condition, and generate a second vibration in a different pattern or at a different interval upon the occurrence of a second condition. For example, the second alert device 355 can be configured to alternately vibrate and stop as the end effector 340 of the second surgical instrument 320 approaches and / or enters a first alert zone, or the second alert device 355 can be configured to vibrate continuously as the end effector 340 of the second surgical instrument 320 approaches and / or enters a second alert zone.

[0067] The second alert device 355 can also be configured as an audible device, such as a speaker configured to provide an audible alert to the surgeon upon the occurrence of a predetermined condition. For example, the second alert device 355 can include a speaker configured to generate a particular sound upon the occurrence of a predetermined condition. Alternatively, the second alert device 355 can include a speaker configured to generate a sound in a particular pattern or at particular intervals upon the occurrence of a predetermined condition, such as when the position of the end effector crosses a predetermined zone / boundary.

[0068] Alternatively, the second alert device 355 can be a visually perceptible device, such as a visual display configured to provide a visual alert to the practitioner upon the occurrence of a predetermined condition. For example, the second alert device 355 can include a light configured to flash upon the occurrence of a predetermined condition. Alternatively, the second alert device 355 can include a plurality of multi-colored lights configured to illuminate and / or flash in a predetermined color or pattern upon the occurrence of a predetermined condition. The display can be integrated into the handpiece or battery, or can be integrated as part of the navigation system, or a combination thereof.

[0069] It is further contemplated that the second alert device 355 can include a combination of audible, tactile, and / or visually perceptible devices. For example, the second alert device 355 can be configured as a combination of an audible device and a tactile device, where the tactile device can be configured to vibrate to provide a first alert and the audible device can be configured to emit a noise to provide a second alert. The first and second alerts can indicate the occurrence of the same predetermined condition, or the first and second alerts can indicate the occurrence of different predetermined conditions. For example, the first alert can be based on the second surgical instrument 320 entering a first region and the second alert can be based on the end effector 340 entering a second region.

[0070] While the second alert device 355 is shown coupled to the switch 350 of the second surgical instrument assembly 300, it is contemplated that the second alert device 355 may be coupled to and / or positioned in other locations. For example, if the second alert device 355 includes a tactile device, the second alert device 355 can be configured as a vibrating member removably attached to the surgeon. The second alert device 355 can be configured as a bracelet worn on the surgeon's wrist or arm so that the surgeon can feel the second alert device 355 vibrate upon the occurrence of a predetermined condition. Alternatively, if the second alert device 355 includes an audible device, the second alert device 355 can be configured as a speaker removably attached to the surgeon. The second alert device 355 can be configured as a Bluetooth-enabled speaker or earpiece worn on the surgeon's head or placed in the surgeon's ear so that the surgeon can hear the noise made by the second alert device 355 upon the occurrence of a predetermined condition.

[0071] While not required, locating the second alert device 355 away from the second surgical instrument 320 has many advantages. For example, one advantage of locating the second alert device 355 away from the second surgical instrument 320 is that the size of the second surgical instrument 320 can be reduced, allowing the second surgical instrument 320 to fit into a smaller space. A smaller second surgical instrument 320 also reduces the obstruction of the surgeon's view of the surgical site. Another advantage of locating the second alert device 355 away from the second surgical instrument 320, particularly in the case of a tactile device, is that the second alert device 355 does not vibrate or affect the movement of the second surgical instrument 320 while still providing an alert or notification to the surgeon. In some medical procedures, the surgeon may rely on the feel and / or touch of the instrument to perform the procedure. For example, the surgeon may rely on the feel or touch of the instrument to recognize changes in torque, which may indicate a change in the consistency / density of the biological material being cut and / or removed. The surgeon's touching and / or contact with the instrument may also indicate when the end effector is spinning idle compared to when it is cutting / removing biological material. In these exemplary situations, as well as in other cases where the surgeon feels feedback and / or a sense of touch with the instrument, which may aid in the accurate execution of a medical procedure, it may be advantageous to have the alert device 355 located away from the second surgical instrument 320, such as on a foot switch 350. During highly technical procedures, a vibrating alert device located on or near the second surgical instrument 320 may increase the likelihood that the second alert device 355 will startle the surgeon and / or the vibrations will impart undesired movement to the second surgical instrument 320, causing the surgeon to move the second surgical instrument 320 to an undesired position. Vibrating the second surgical instrument 320 may also cause the end effector 340 to grasp or break biological material, resulting in undesired results such as contacting critical anatomical features or removing / damaging biological material that should not be removed during the medical procedure.

[0072] The second surgical tool assembly 300 may also include a tracking device 330. The tracking device 330 may be coupled to the handpiece 325 of the second surgical tool 320. The tracking device 330 is similar to that described above for the first surgical tool assembly.

[0073] The surgical system 10 can include a third surgical instrument assembly 400 in communication with the navigation system 100. For example, the third surgical instrument assembly 400 can include a third surgical instrument 420, such as an ultrasonic instrument that includes a handpiece 425. The handpiece 425 can be coupled to a console 410 configured to control the operation of various components of the third surgical instrument 420. The handpiece 425 can be configured to include a handle or grip portion for a surgeon to grasp while performing a medical procedure.

[0074] The third surgical instrument 420 may also include a third instrument processor 415 and a motor 445. The third instrument processor 415 may be located within the console 410 of the third surgical instrument assembly 400. The motor 445 may be located within the handpiece 425 of the third surgical instrument 420. The third instrument processor 415 and the motor 445 may be in communication with each other. The motor 445 may include a piezoelectric element configured to expand and contract upon application of an electric current to the piezoelectric element. The piezoelectric element may include multiple disk-shaped piezoelectric elements arranged end-to-end in a stacked configuration. The third instrument processor 415 may be configured to control the operation of the motor 445 and, therefore, the third surgical instrument 420. For example, the third surgical instrument 420 may include an end effector 440, such as an ultrasonic tip assembly. The end effector 440 may include an ultrasonic tip assembly including a horn that vibrates an ultrasonic tip portion at ultrasonic speeds when the piezoelectric element(s) expand and contract. Additionally, the ultrasonic tip assembly may also include an outer sheath disposed at least partially over the horn, excluding the ultrasonic tip portion. The end effector 440 may be coupled to the handpiece 425 of the third surgical instrument 420 such that a motor 445 may be operably coupled to the end effector 440. For example, the motor 445 may be configured to drive the ultrasonic tip assembly 440 to abrade and / or remove biological tissue from a surgical site. The third instrument processor 415 may be in communication with the motor 445 and configured to control the flow of current to the piezoelectric element(s) to control the operation of the motor 445 and, therefore, the ultrasonic tip assembly 440. Additionally, the third instrument processor 415 may be in communication with the navigation processor 140 and configured to exchange data related to the position and / or orientation of the third surgical instrument 420, as well as data related to the operation of the third surgical instrument 420. For example, the third instrument processor 415 and the navigation processor 140 can be configured to communicate data with each other related to the operation of the third surgical instrument 420 based on the position and / or orientation of the third surgical instrument 420 detected by the surgical navigation system 100.

[0075] The third surgical tool assembly 400 may also include a power source (not shown). The power source may be coupled to the console 410 of the third surgical tool assembly 400 and configured to provide energy to the motor 445 of the third surgical tool 420 to drive the end effector 440. For example, the power source may include a removable battery pack. It is further contemplated that the console 410 may be provided with a cord configured to be plugged into an outlet connected to an electrical grid to provide energy to the third surgical tool assembly 400. The power source may be in electrical communication with the third tool processor 415 and / or the motor 445 and configured to selectively power the motor 445 to drive the end effector 440.

[0076] The third surgical instrument assembly 400 can also include a switch 450, such as a footswitch, pedal, or button, operably coupled to the third instrument processor 415. The switch 450 can be configured to generate and / or communicate a signal to the third instrument processor 415 based on a user input that controls operation of the third surgical instrument 420. For example, the switch 450 can include a first position, a second position, and multiple intermediate positions between the first and second positions. The first position can be configured as an off position such that, when the third instrument processor 415 detects that the switch 450 is in the first position, the third instrument processor 415 blocks the flow of energy from the power source to the motor 445, preventing operation of the third surgical instrument 420. Alternatively, the third instrument processor 415 can be configured to, when the first instrument processor 415 detects that the switch 450 is in the second position, allow a maximum flow of energy from the power source to the motor 445, thereby allowing the third surgical instrument 420 to operate at a maximum displacement. When the third instrument processor 415 detects that the switch 450 is in one of the intermediate positions, the third instrument processor 415 can be configured to allow a level of energy to flow from the power source to the motor 445 that corresponds to the position of the switch 450 between the first and second positions, thereby allowing the third surgical instrument 420 to operate at an intermediate level of displacement. For example, when the third instrument processor 415 detects that the switch 450 is positioned halfway (50%) between the first and second positions, the third instrument processor 415 can be configured to allow a level of energy to flow from the power source to the motor 445 that allows the third surgical instrument 420 to operate at a speed that is 50% of its maximum displacement. Alternatively, the third instrument processor 415 can be configured to allow a maximum flow of energy to flow from the power source to the motor 445 whenever the switch 450 is in a position other than the first position, thereby allowing the third surgical instrument 420 to operate at its maximum displacement when the switch 450 is in either the second or intermediate position.

[0077] The third surgical instrument assembly 400 can also include a third alert device 455. The third alert device 455 can include an audible, tactile, and / or visually perceptible device. The third alert device 455 can be configured to communicate with the third instrument processor 415. The third instrument processor 415 can be configured to send a signal to activate the third alert device 455 to provide a warning or notification based on preprogrammed conditions or settings. For example, as described above, the surgeon can use the user input 130 to input predetermined conditions and / or settings into the surgical navigation system 100, such as selecting cortical borders, nerves, blood vessels, or similar critical anatomical structures that the surgeon wishes to avoid and establishing regions or zones surrounding these anatomical structures. For example, the surgeon can use the user input 130 of the surgical navigation system 100 to define regions or zones within the patient data. This can include identifying critical anatomical features, such as nerves or blood vessels, and assigning them to zones. This may include identifying additional zones that include regions or areas surrounding the critical anatomical feature, such as defining a second zone that surrounds the critical anatomical feature but is spaced from the boundary of the critical anatomical feature. This may also include defining additional subsequent zones, such as a third zone that surrounds the second zone and is spaced from the boundary of the critical anatomical feature by a distance greater than the distance the second zone is spaced from the critical anatomical feature. In this exemplary configuration, the end effector 440 is likely to contact the outermost zone first, thereby triggering the alert device 455 to generate a first alert. The end effector 440 may then contact the alert zone next closest to the critical anatomical feature and trigger the alert device 455 to generate a second alert. The first and second alerts are configured to notify the surgeon that the end effector 440 has entered the respective zones assigned to the first and second alerts.

[0078] Additionally, the surgeon may use user input 130 to select and / or input a target location, target trajectory, or similar feature of a surgical path to help guide the surgeon in performing a medical procedure. The third instrument processor 415 may be configured to transmit a signal to activate a third alert device 455 when the end effector 440 of the third surgical instrument 420 enters one of the regions and / or zones surrounding the anatomical structure and defined by the surgeon, based on data provided by navigation processor 140. The third instrument processor 415 may also be configured to transmit a signal to activate a third alert device 455 when the end effector 440 of the third surgical instrument 420 deviates from the trajectory and / or when the end effector 440 reaches a target location, based on data provided by navigation processor 140. For example, the third alert device 455 can be activated to generate at least one of an audible, tactile, or visually perceptible alert based on the surgical navigation system 100 determining that the end effector 440 and / or the third surgical instrument 420 are not properly aligned with a target trajectory established as part of a panned surgical path. In this exemplary configuration, the third alert device 455 can generate a tactile alert, such as vibrating the switch 450, to notify the surgeon that the end effector 440 is not properly aligned with the target trajectory. Once the end effector 440 is properly aligned with the target trajectory, the third alert device 455 can be deactivated. The third alert device 455 can similarly be configured to be activated to generate at least one of an audible, tactile, or visually perceptible alert based on the surgical navigation system 100 determining that the end effector 440 and / or the third surgical instrument 420 have reached a target position determined by the surgeon in the panned surgical path. For example, the third alert device 455 may generate a tactile alert, such as vibrating the switch 450, to notify the surgeon that the end effector 440 has reached a target position, such as a suitable depth.It is also contemplated that once the end effector 440 reaches the target position, the control console can be configured to stop the motor, and therefore the end effector 340, so that the end effector 340 does not exceed the target position.

[0079] In one example configuration, the third alert device 455 may be configured as described above for the first and second alert devices.

[0080] The third surgical tool assembly 400 may also include a tracking device 430. The tracking device 430 may be coupled to the handpiece 425 of the third surgical tool 420. The tracking device 430 is similar to that described above for the other surgical tool assemblies.

[0081] The above-described surgical instrument assemblies 200, 300, 400 are intended to be exemplary instruments and / or configurations within the surgical system 10, but are not intended to be limiting. Other types and configurations of surgical instrument assemblies are also contemplated. While multiple exemplary surgical instrument assemblies 200, 300, 400 are described as being part of the surgical system 10 and in communication with the surgical navigation system 100, it is contemplated that the surgical system 10 may have only a single surgical instrument assembly 200, 300, 400 and navigation system 100. Furthermore, while the surgical system 10 illustrated in Figures 1A and 1B includes three surgical instrument assemblies 200, 300, 400 and a single surgical navigation system 100, it is contemplated that the surgical system 10 may be configured to include any combination of surgical instrument assemblies 200, 300, 400 and / or surgical navigation system 100. For example, the surgical system 10 may include a single surgical instrument assembly 200 , 300 , 400 and multiple surgical navigation systems 100 .

[0082] 2, an exemplary configuration of an operating room or surgical facility for performing a medical procedure on a patient 20 using the surgical system 10 described above is illustrated. The surgical system 10, including the surgical navigation system 100 and at least one of the surgical instrument assemblies 200, 300, 400 described above, can be positioned in an operating room surrounding the patient 20 and / or the surgical site 30 where the medical procedure will be performed.

[0083] While only the second surgical instrument assembly 300 is shown in FIG. 2 , it should be understood that this is merely an exemplary configuration of the surgical system 10, and it is contemplated that any number of surgical instrument assemblies 200, 300, 400 may be disposed within the operating room. As described above, the second surgical instrument assembly 300 comprises a second surgical instrument 320 including an end effector 340 and a tracking device 330. The tracking device 330 includes a plurality of markers 335 that are identifiable and / or trackable by the surgical navigation system 100. The second surgical instrument 320 is coupled to a console 310 located remotely from the second surgical instrument 320. Additionally, the second surgical instrument assembly 300 also includes a switch 350 located remotely from the patient 20 and coupled to the console 310. The switch 350 communicates with the second surgical instrument 320 via a second instrument processor 315 (not shown) housed within the console 310.

[0084] Although not shown in FIG. 2 , the second surgical instrument assembly 300 also includes the second alert device 355 described above. Depending on the configuration of the second alert device 355, the second alert device 355 can be located on the switch 350, elsewhere on the surgeon's body, and / or in a location within the operating room that is visible to the surgeon. For example, as described above, a second alert device 355 including a tactile member may be located on the surgeon's wrist, ankle, or the like. Alternatively, a second alert device 355 including an audible member may be located at the surgeon's ear. In yet another configuration, the second alert device 355 includes a visual device and can be located on the display unit 120 of the surgical navigation system 100 or a similar location that is visible to the surgeon without obstructing or interfering with the surgeon's view of the surgical site 30. In other configurations, the second alert device is a foot switch and is located under the operating room table, making it difficult to see during surgery.

[0085] Although not previously mentioned, it is contemplated that the surgical system 10 may further include an imaging system 500, such as a CT or MRI imager. The imaging system 500 may include a scanner 510 and a display unit 520. The scanner 520 may be used to capture images of the surgical site 30 on the patient 20 and display the images on the display unit 520. For example, the scanner may include a C-arm configured to rotate around the patient 20 to generate multiple images of the surgical site 30. The imaging system 500 may also include a processor (not shown) having software capable of capturing the multiple images captured by the scanner 510 and generating two-dimensional images and / or three-dimensional models of the surgical site 30, as known to those skilled in the art. The display unit 520 may be configured to display the final two-dimensional images and / or three-dimensional models.

[0086] Additionally, the imaging system 500 can communicate with the navigation processor 140 of the surgical navigation system 100. The imaging system 500 can be configured to communicate with the navigation processor 140 via a wired and / or wireless connection. For example, the imaging system 500 can be configured to provide pre-operative and / or intra-operative image data, such as a final two-dimensional image and / or a three-dimensional model of the surgical site 30, to the navigation processor 140. The navigation processor 140 can then be configured to provide the final two-dimensional image and / or three-dimensional model to the navigation display unit 120, where the surgeon can use the user input 130 or an algorithm to identify and / or define corresponding regions and / or zones around critical anatomical structures. For example, the surgeon can use the user input 130 of the surgical navigation system 100 to define alert zones around vertebral bodies, nerves, or blood vessels that the surgeon wants to avoid when performing a medical procedure. The surgeon can use the user input 130 of the surgical navigation system 100 to input and / or modify planned surgical paths, boundaries, or alert zones to be used during the performance of a medical procedure.

[0087] Referring to FIG. 3 , an exemplary schematic diagram of a surgical site 30 on a patient 20 during a medical procedure is shown from the perspective of a surgeon. The exemplary schematic diagram of FIG. 3 depicts an exemplary placement of the above-described surgical system 10 during a medical procedure, including a second surgical instrument assembly 300. The second surgical instrument assembly 300 includes a second surgical instrument 320, including a handpiece 325 and an end effector 340, positioned proximate the surgical site 30 and within the field of view of the surgeon. Additional components of the second surgical instrument assembly 300 are coupled to the second surgical instrument 320 but are positioned remotely from the second surgical instrument 320 and outside the field of view of the surgeon. For example, the surgical navigation system 100, console 310, switch 350, and alert device 355 can all be positioned remotely from the second surgical instrument 320 and outside the field of view of the surgeon while the surgeon is concentrating on the surgical site. This may reduce obstructions blocking the surgeon's view of the surgical site, improving the surgeon's ability to focus on the surgical site 30 and / or perform the medical procedure.

[0088] 4A-5C, various schematic views of the surgical system 10 described above during a medical procedure are illustrated. The various schematic views of the surgical system 10 include one or more of the surgical instruments 220, 320, 420 described above in various orientations relative to the patient 20 to further illustrate the operation of the surgical system 10. A surgical instrument 220, 320, 420, such as a second surgical instrument 320, is shown in a first position relative to a surgical site 30 on the patient 20. The surgical instrument 220, 320, 420 can have a console or housing 210, 310, 410 having an instrument processor 215, 315, 415. As noted above, the instrument processor 215, 315, 415 can be in communication with the navigation processor 140 of the navigation system. The surgical instrument 220, 320, 420 may also have a switch 250, 350, 450, such as a trigger, hand switch, or foot switch, coupled to the console or housing 210, 310, 410 and in communication with the instrument processor 215, 315, 415. An alert device 255, 355, 455 may be coupled to the switch 250, 350, 450 and in communication with the instrument processor 215, 315, 415. Although not shown, as noted above, the alert device 255, 355, 455 need not be coupled to the switch 250, 350, 450. However, it is contemplated that the alert device 255, 355, 455 may be separate from the switch 250, 350, 450. For example, the alert device 255, 355, 455 may be coupled to the console or housing 210, 310, 410 and communicate either wired or wirelessly with the instrument processor 215, 315, 415. It is further contemplated that the alert device 255, 355, 455 may be a standalone device, such as a bracelet or armband worn by the practitioner, which communicates wirelessly with the instrument processor 215, 315, 415.

[0089] Additionally, as described above, the surgeon can use the surgical navigation system 100 to identify and / or define various boundaries, regions, target trajectories, target locations, etc., in pre-operative and / or intra-operative patient data, such as CT or MRI scans. For example, as shown in FIGS. 4A-4C , the surgeon can use the surgical navigation system 100 to select and / or define virtual boundaries (Boundaries 1, 2, 3) and / or alert zones (Zones 1, 2, 3) relative to important anatomical structures or boundaries, such as the central foramen, vertebral walls, nerves, or blood vessels, within the surgical site 30. This may include defining multiple virtual boundaries (Boundaries 1, 2, 3) and / or alert zones (Zones 1, 2, 3) at various distances from the important anatomical structures. For example, as shown in FIGS. 4A-5C , the surgical site 30 includes the vertebrae on which the medical procedure will be performed. A first virtual boundary, Boundary 1, can be defined relative to an important anatomical structure, such as the periphery of the spinal cord. Boundary 1 can be manually defined by the surgeon using the navigation system 100. However, Boundary 1 can also be selected by the surgeon from a pre-populated list of virtual boundaries provided by boundary generation software in the navigation system 100. As described above, the navigation system 100 can include software with a boundary generator. The navigation processor 140 can be configured to provide a list of one or more virtual boundaries based on various data points selected or entered by the surgeon. For example, the surgeon can select the location of the surgery, the type of surgery, the type of surgical instrument 200, 300, 400 to be used, the type of device or implant to be inserted, etc., and the boundary generator can be configured to define one or more virtual boundaries for the user to select. Additionally, the boundary generator can be configured to define alert zones (Zones 1, 2, 3, 4). A first alert zone, Zone 1, can be defined at a first distance from a critical anatomical structure, such as the lateral boundary of the spinal cord. Zone 1 can be defined as the volume between a first virtual boundary, Boundary 1, and a second virtual boundary, Boundary 2. Boundary 2 is surgeon-definable, including by the surgeon inputting and / or selecting a desired depth for Zone 1, and the navigation system is configured to define Boundary 2 based on this depth.For example, the navigation system 100 can be configured to prompt the surgeon to input and / or select a depth, and the navigation system can then define Boundary 2 based on this depth. Alternatively, Boundary 2 can be selected by the surgeon from a pre-populated list of virtual boundaries provided by boundary generation software in the navigation system 100. For example, the navigation system 100 can be configured to provide a pre-populated list of end effectors 240, 340, 440, including default depths for the alert zones of each of the end effectors 240, 340, and 440, and the navigation system can be configured to define Zone 1 based on the end effector 240, 340, 440 selected by the surgeon.

[0090] In one example configuration, the boundary generator can be configured to generate a second virtual boundary, Boundary 2, at a default distance from a first virtual boundary, Boundary 1, based at least in part on the surgical procedure being performed. For example, the boundary generator can be configured to generate Boundary 2 to be 2 millimeters from Boundary 1. A surgeon can edit or modify the distance or depth between Boundary 1 and Boundary 2 using the graphical user interface (GUI) 150 and / or user input 130. The volume defined between Boundary 1 and Boundary 2 can define a first alert zone, Zone 1.

[0091] A second alert zone, Zone 2, can be defined at a second distance from the critical anatomical structure, such that the second distance is greater than the first distance. Zone 2 can be defined as the volume between Boundary 2 and a third virtual boundary, Boundary 3. Boundary 3 can be defined by the surgeon, or Boundary 3 can be selected by the surgeon from a pre-populated list of virtual boundaries provided by boundary generation software in the navigation system 100. For example, the boundary generator can be configured to generate Boundary 3 at a default distance from Boundary 2 based at least in part on the surgical procedure being performed. The surgeon can edit or modify the distance or depth between Boundary 2 and Boundary 3 using the graphical user interface (GUI) 150 and / or user input 130. The third alert zone, Zone 3, can be defined at and / or include the boundary of the critical anatomical structure. Additionally, a fourth virtual boundary, Boundary 4, can be defined at the perimeter and / or boundary of a biological structure, such as a vertebra. It is also contemplated that the surgical navigation system 100 may be configured to define the virtual boundaries (Boundaries 1, 2, 3, 4) and / or alert zone(s) (Zones 1, 2, 3, 4) based on information selected or input by a medical professional. For example, the surgical navigation system 100 may be configured to define the alert zones (Zones 1, 2, 3, 4) based on one or more of the following items input by the medical professional: the type of surgery to be performed, the surgical position of the patient, the type of implant 275 to be used, the type of surgical instrument 220, 320, 420 to be used, and / or the type of end effector 240, 340, 440. The medical professional may then have the opportunity to modify or change the virtual boundaries (Boundaries 1, 2, 3, 4) and / or alert zone(s) (Zones 1, 2, 3, 4) defined by the surgical navigation system 100 using the user input device 130 and / or the graphical user interface (GUI) 150. Again, it is contemplated that the various zones may be automatically generated based on algorithms that recognize certain important anatomical structures in the image data.

[0092] During a medical procedure to remove biological tissue from the surfaces of vertebrae at a surgical site, the end effector 240, 340, 440 of the surgical instrument 220, 320, 420 may approach one of various virtual boundaries (Boundaries 1, 2, 3, 4) and / or alert zones (Zones 1, 2, 3, 4). As described above, the surgical navigation system 100 can be configured to track the position and / or orientation of the surgical instrument 220, 320, 420 relative to the various virtual boundaries (Boundaries 1, 2, 3, 4) and / or alert zones (Zones 1, 2, 3, 4) and further communicate a signal or command to the instrument processor 215, 315, 415 to activate an alert device 255, 355, 455 to notify the surgeon when the end effector 240, 340, 440 approaches and / or enters one of the various virtual boundaries (Boundaries 1, 2, 3, 4) and / or alert zones (Zones 1, 2, 3, 4). For example, in the case of virtual boundaries (Boundaries 1, 2, 3, 4), the surgical navigation system 100 can be configured to track the position and / or location of the surgical instrument 220, 320, 420 relative to the various virtual boundaries (Boundaries 1, 2, 3, 4) and communicate a signal or command to the instrument processor 215, 315, 415 to activate the alert device 255, 355, 455 to notify the surgeon when the end effector 240, 340, 440 is adjacent and / or distal to a virtual boundary (Boundary 1, 2, 3, 4). For example, the instrument processor 215, 315, 415 activates the alert device 255, 355, 455 based on the tip of the end effector being positioned adjacent to a virtual boundary (Boundary 1, 2, 3, 4). Based on the tip of the end effector being positioned a predetermined distance distal to the virtual boundary (Boundary 1, 2, 3, 4), the instrument processor 215, 315, 415 activates the alert device 255, 355, 455. The instrument processor 215, 315, 415 may be configured to define a distance such that the tip is positioned 0.5 mm, 1 mm, 2 mm, 3 mm, etc. distal to the virtual boundary (Boundary 1, 2, 3, 4). The surgical navigation system 100 may be configured to allow the surgeon to assign specific types of alerts to each of the various virtual boundaries (Boundaries 1, 2, 3, 4) and / or alert zones (Zones 1, 2, 3, 4).This may include audible, tactile, and / or visual alerts to notify the surgeon. The audible, tactile, and / or visual alerts may be coupled to a switch 250, 350, 450, such as a footswitch or trigger that the surgeon touches to operate the surgical instrument. As noted above, locating an alert device 255, 355, 455 that includes a tactile alert on a switch 250, 350, 450 has various advantages. This may be particularly true when the alert device 355, 455 that includes a tactile alert is located in a switch 350, 450 that is located away from the surgical instrument 320, 420, as is the case in the exemplary second and third surgical instrument assemblies 300 and 400 described above.

[0093] Once the alert device 255, 355, 455 is activated, the system 10 can be configured to allow the alert device 255, 355, 455 to be deactivated by the operator. This can be accomplished by pressing a button, switch, or icon configured to deactivate the alert device 255, 355, 455. The button, switch, and / or icon for deactivating the alert device(s) 255, 355, 455 can be located on the navigation system 140. For example, the navigation display 120 can be configured as a touchscreen that allows the user to select an icon for deactivating the alert device(s) 255, 355, 455. It is further contemplated that the operator can activate a button or switch on the user input 130 of the navigation system 100 to deactivate the alert device(s) 255, 355, 455. It is contemplated that a button or switch for disabling the alert device(s) 255, 355, 455 may be located on the housing 210 or console 310, 410 of the surgical instrument assembly 200, 300, 400, and that the surgeon may actuate the button or switch to disabling the alert device(s) 255, 355, 455. Alternatively, it is contemplated that this may be accomplished by actuating the trigger and / or foot switch 250, 350, 450 in a predetermined pattern or sequence to disabling the alert device 255, 355, 455. For example, the system may be configured such that double-tapping the switch 250, 350, 450 after the alert device 255, 355, 455 has been activated will disabling the alert device 255, 355, 455, allowing the surgeon to continue the procedure without interruption. The system 10 may be configured so that deactivating the alert device 255, 355, 455 requires a surgeon action, such as a double tap on the switch 250, 350, 450, to ensure that the surgeon acknowledges and / or confirms that they received the alert and has taken positive and clear steps to deactivate the alert device 255, 355, 455.In this way, accidental deactivation of the alert device 255, 355, 455 due to the surgeon not receiving and / or not recognizing that the alert device 255, 355, 455 has been activated can be prevented.

[0094] Additionally, the surgical navigation system 100 may be configured to provide an alert by manipulating the speed of the motor 245, 345, 445, and therefore the speed at which the end effector 240, 340, 440 operates, based on the position and / or orientation of the surgical instrument 220, 320, 420 relative to one or more of the virtual boundaries (Boundaries 1, 2, 3, 4) and / or alert zones (Zones 1, 2, 3, 4). For example, the surgical navigation system 100 may be configured to slow the motor 245, 345, 445 from a maximum cutting speed to a minimum cutting speed based on the position of the surgical instrument 220, 320, 420 relative to one or more of the virtual boundaries (Boundaries 1, 2, 3, 4) and / or alert zones (Zones 1, 2, 3, 4).

[0095] This can include the surgical navigation system 100 sending a signal to the second instrument processor 315 to reduce the power of the motor 345 of the second surgical instrument 320, such as a high-speed cutting burr, when the end effector 340 is adjacent and / or distal to the second virtual boundary, Boundary 2, and / or enters the first alert zone, Zone 1, to slow the rotation of the end effector 340 from a current operating speed, such as 75,000 RPM, to a lower speed, such as 60,000 RPM, that is still effective for cutting tissue. Manipulation of the speed of the motor 245, 345, 445 of the surgical instrument 220, 320, 420, and therefore the rotation of the end effector 240, 340, 440, can be due to the instrument processor 215, 315, 415 being configured to adjust the current and / or voltage supplied to the motor 245, 345, 445. For example, to slow down the motor 245, 345, 445 of the surgical instrument 220, 320, 420, the instrument processor 215, 315, 415 can be configured to reduce the voltage and / or current supplied to the motor 245, 345, 445. The instrument processor 215, 315, 415 can be configured to gradually decrease the current and / or voltage supplied to the motor 245, 345, 445, thereby gradually slowing down the rotation of the end effector 240, 340, 440. This gradual decrease in current and / or voltage can cause the motor 245, 345, 445 to drift from a first cutting speed to a second cutting speed, or vice versa. Similarly, the tool processor 215 , 315 , 415 can be configured to accelerate the motor 245 , 345 , 445 of the surgical tool 220 , 320 , 420 by increasing the voltage and / or current supplied to the motor 245 , 345 , 445 .

[0096] The slowing down of the motor 245, 345, 445 of the surgical instrument 220, 320, 420 can provide an alert or notification to the surgeon in the form of a tactile alert felt by the surgeon at the handpiece 225, 325, 425. It is further contemplated that the slowing down of the motor 245, 345, 445 of the surgical instrument 220, 320, 420 can also provide an alert or notification to the surgeon in the form of an audible alert, such as the surgeon hearing a change in the pitch of the motor 245, 345, 445 or perceiving a change in cutting effect as the motor 245, 345, 445 slows down from a maximum cutting speed to a minimum cutting speed. While it is not necessary to slow the motor 245, 345, 445 from the maximum cutting speed to the minimum cutting speed, it is desirable for the motor 245, 345, 445 not to slow down below a predetermined minimum cutting speed to prevent the end effector 240, 340, 440 from biting or grabbing, going off-line, and / or going off-track, which could cause the end effector 240, 340, 440 to contact and / or damage critical anatomical structures. It is further contemplated that the surgical navigation system 100 can be configured to disable or stop the motor 245, 345, 445 when the end effector 240, 340, 440 approaches critical anatomical structures, thereby preventing the end effector 240, 340, 440 from contacting and / or damaging critical anatomical structures. It is also contemplated that the tracking device of the surgical instrument 220, 320, 420 may be blocked from the field of view of the navigation system during the process of tracking the surgical instrument 220, 320, 420, and thus the end effector 240, 340, 440. It is further contemplated that the navigation system 100 may be configured to disable or stop the motor 245, 345, 445 to prevent manipulation of the end effector 240, 340, 440 if the tracking device of the surgical instrument 220, 320, 420 is out of the field of view of the navigation system 100 for a predetermined period of time to prevent manipulation of the surgical instrument 220, 320, 420 if its location is unknown within patient space.Exemplary navigation systems and / or methods configured to prevent operation of a surgical instrument when out of the field of view of the navigation system are described in U.S. Patent Publication No. 2016 / 0242858, the entire contents of which are incorporated herein by reference.

[0097] 4A, a surgical instrument 220, 320, 420, such as second surgical instrument 320, is shown in a first position and / or orientation relative to a patient's surgical site 30. The surgical instrument 220, 320, 420 may be configured to remove biological tissue from the surgical site 30. In the first position, the end effector 240, 340, 440 is spaced apart from a defined virtual boundary (Boundary 1, 2, 3) and / or is positioned outside the volume defining the alert zone (Zone 1, 2, 3). In this exemplary scenario, the surgical navigation system 100 determines that the end effector 240, 340, 440 is spaced from the defined virtual boundaries (Boundaries 1, 2, 3) and / or outside the defined alert zones (Zones 1 and 2) and operates the switches 250, 350, 450 to allow the surgical instrument 220, 320, 420 to operate under normal operating conditions when actuating the end effector 240, 340, 440. The alert devices 255, 355, 455 may be configured to be deactivated in this scenario. The nested nature of Boundaries 1, 2, and 3 and Zones 1, 2, and 3 (one more distal than the other) allows for the provision of gradually increasing alerts to ensure the surgeon is aware that the surgical instrument 220, 320, 420 is approaching a critical anatomical structure and / or target depth.

[0098] 4B, the surgical instrument 220, 320, 420 is shown in a second position relative to the patient's surgical site 30. In the second position, the end effector 240, 340, 440 is removing tissue while at least partially entering a second alert zone, Zone 2. In this example, Zone 2 is defined between Boundary 3 and Boundary 2. In this exemplary scenario, the surgical navigation system 100 can determine that the end effector 240, 340, 440 is positioned adjacent to and / or distal to Boundary 3 and / or enters a volume corresponding to the second alert zone, Zone 2, and can trigger one of the various alerts described above. For example, the surgical navigation system 100 can be configured to send a signal to the instrument processor 215, 315, 415 and / or navigation processor to activate an alert device 255, 355, 455 because the end effector 240, 340, 440 is located adjacent to and / or distal to boundary 3 and / or has entered a second alert zone, Zone 2. The alert device 255, 355, 455 can be configured to provide a tactile alert A, such as vibrating a switch 250, 350, 450, depending on the type of alert assigned to the second alert zone, Zone 2. Alternatively, the alert device 255, 355, 455 can be configured to provide a visual alert B, such as a flashing light on a display screen of the navigation system. In yet another configuration, the alert device 255, 355, 455 can be configured to provide an audible alert C, such as a beep. Additionally, the surgical navigation system 100 can be configured to send a signal to the instrument processor 215, 315, 415 to reduce the power of the motor 245, 345, 445 of the surgical instrument 220, 320, 420 to reduce the rotation of the end effector 240, e.g., a surgical burr 340, 440, from a first cutting speed of greater than seventy thousand revolutions per minute (70,000 RPM) to a second cutting speed of less than 70,000 revolutions per minute and greater than sixty thousand revolutions per minute (60,000 RPM).It is further contemplated that various combinations of alerts may be used, such as where alert devices 255, 355, 455 generate a combination of tactile alert A and visual alert B as shown in FIG. 4B.

[0099] 4C, the second surgical instrument 220, 320, 420 is shown in a third position relative to the patient's surgical site 30. In the third position, the end effector 240, 340, 440 is distal to Boundary 2 and / or has entered Zone 1, a first alert zone defined between Boundary 1 and Boundary 2, while removing tissue. In this example scenario, the surgical navigation system 100 can identify that the end effector 240, 340, 440 has entered Zone 1, the first alert zone, and can trigger one of the various alerts described above. For example, the surgical navigation system 100 can be configured to send a signal to the instrument processor 215, 315, 415 indicative of the position of the end effector 240, 340, 440 relative to Boundary 2 and / or Zone 1. The signal from the surgical navigation system 100 may comprise a command to the instrument processor 215, 315, 415 to activate the alert device 255, 355, 455 when the end effector 240, 340, 440 is located adjacent to and / or distal to boundary 2 and / or enters a first alert zone, Zone 1. Alternatively, it is contemplated that the signal from the surgical navigation system 100 may include the position of the end effector 240, 340, 440 relative to boundary 2 and / or Zone 1, and that the instrument processor 215, 315, 415 may be configured to activate the alert device 255, 355, 455 when the surgical navigation system 100 indicates that the end effector 240, 340, 440 is located adjacent to and / or distal to boundary 2 and / or has entered a first alert zone, Zone 1. The alert device 255, 355, 455 can be configured to provide a tactile alert A, such as vibrating the switch 250, 350, 450, depending on the type of alert assigned to the first alert zone, Zone 1. Alternatively, the alert device 255, 355, 455 can be configured to provide a visual alert B, such as a flashing light. In yet another configuration, the alert device 255, 355, 455 can be configured to provide an audible alert C, such as a beep.Additionally, the surgical navigation system 100 can be configured to send a signal to the instrument processor 215, 315, 415 to reduce the power of the motor 245, 345, 445 of the surgical instrument 220, 320, 420, slowing the rotation of the end effector 240, 340, 440 from 75,000 RPM to 60,000 RPM. Alternatively, the surgical navigation system 100 can be configured to disable or stop the rotation of the end effector 240, 340, 440 when it enters a first alert zone, Zone 1, to prevent the end effector 240, 340, 440 from moving into critical anatomical structures. This prevents the end effector 240, 340, 440 from damaging critical anatomical structures. It is further contemplated that various combinations of alerts may be used, such as where alert devices 255, 355, 455 generate a combination of tactile alert A, visual alert B, and audible alert C, as shown in FIG. 4C.

[0100] Referring to FIG. 4D , the second surgical instrument 220, 320, 420 is shown in a fourth position relative to the patient's surgical site 30. As shown in FIG. 4D , the surgical navigation system and / or medical professional have simply selected and / or defined two alert zones, including a first alert zone, Zone 1, and a second alert zone, Zone 2. Zone 2 represents a critical anatomical structure, such as a central foramen. Zone 1 is defined between Boundary 1 and Boundary 2, where Boundary 1 is the recognized perimeter of the critical anatomical structure, i.e., the boundary of the central foramen. As described above, this boundary can be recognized by a segmentation algorithm. In the fourth position, the end effector 240, 340, 440 is positioned adjacent to and / or distal to Boundary 2 and / or has entered the first alert zone, Zone 1, while removing tissue. In this example scenario, the surgical navigation system 100 can identify that the end effector 240, 340, 440 is positioned adjacent to and / or distal to boundary 2 and / or enters the first alert zone, Zone 1, and can trigger one of the various alerts described above. For example, the surgical navigation system 100 can be configured to send a signal to the instrument processor 215, 315, 415 indicating the position of the end effector 240, 340, 440 relative to boundary 2 and / or Zone 1. The signal from the surgical navigation system 100 can include a command to the instrument processor 215, 315, 415 to activate the alert device 255, 355, 455 when the end effector 240, 340, 440 is positioned adjacent to and / or distal to boundary 2 and / or enters the first alert zone, Zone 1.Alternatively, it is contemplated that the signal from the surgical navigation system 100 may include the position of the end effector 240, 340, 440 relative to boundary 2 and / or zone 1, and further, the instrument processor 215, 315, 415 may be configured to activate the alert device 255, 355, 455 when the surgical navigation system 100 indicates that the end effector 240, 340, 440 is positioned adjacent and / or distal to boundary 2 and / or has entered the first alert zone, Zone 1. The alert device 255, 355, 455 may be configured to provide a tactile alert A, such as vibrating the switch 250, 350, 450, depending on the type of alert assigned to boundary 2 and the first alert zone, Zone 1, respectively. Alternatively, the alert device 255, 355, 455 may be configured to provide a visual alert B, such as a flashing light. In yet another configuration, the alert device 255, 355, 455 may be configured to provide an audible alert C, such as a beep. Additionally, the surgical navigation system 100 can be configured to send a signal to the instrument processor 215, 315, 415 to reduce the power of the motor 245, 345, 445 of the surgical instrument 220, 320, 420, thereby decreasing the rotation of the end effector 240, 340, 440 from a first cutting speed greater than seventy thousand revolutions per minute (70,000 RPM) to a second cutting speed less than 70,000 revolutions per minute and greater than sixty thousand revolutions per minute (60,000 RPM). Alternatively, when the end effector 240, 340, 440 is positioned adjacent and / or distal to Boundary 2 and / or enters a first alert zone, Zone 1, the surgical navigation system 100 can be configured to disable or stop rotation to prevent the end effector 240, 340, 440 from contacting and / or entering a second alert zone, Zone 2, defined around critical anatomical structures, thereby preventing the end effector 240, 340, 440 from contacting and / or damaging critical anatomical structures.It is further contemplated that various combinations of alerts may be used, such as the alert device 255, 355, 455 generating a combination of tactile alert A, visual alert B, and audible alert C.

[0101] 5A-5F, various schematic diagrams of one of the above-described surgical instrument assemblies 200, 300, 400 are illustrated, including the surgical instruments 220, 320, 420 in various orientations relative to the patient 20. Referring to FIG. 5A, a surgical instrument 220, 320, 420, such as a first surgical instrument 220, is illustrated in a first position relative to a surgical site 30 on a patient. The surgical instrument 220, 320, 420 can be configured to drill holes and remove tissue from the surgical site 30 or to drive screws, such as pedicle screws, into the surgical site. In this scenario, the surgeon can select and / or define one or more planned implant orientations, such as planned screw orientations, including a target trajectory axis-T and a target depth T. Alternatively, the navigation processor 140 can receive a planned surgical path automatically generated based on a segmentation of the patient image data and the planned orientation of the medical device or implant 275 to be inserted during surgery.

[0102] The target trajectory axis-T may include a desired orientation of the implant 275 to be inserted during surgery and may be used to align the surgical instrument 220, 320, 420, and thus one or more end effectors 240, 340, 440, when preparing the anatomy to receive the screw. The target depth T may have a desired depth or location in a known coordinate system. The target depth may also be referred to as a boundary and may be configured as a partial plane perpendicular to the target trajectory. It is further contemplated that the surgical navigation system 100 may be configured to define the target trajectory axis-T and target depth T based on information selected or input by a medical professional. For example, the surgical navigation system 100 may be configured to define the target trajectory axis-T and target depth T based on one or more of the following input by a medical professional: the type of surgery to be performed, the type or size of the implant 275 to be used, the type of surgical instrument 220, 320, 420 to be used, and / or the type of end effector 240, 340, 440.

[0103] In the first position, all portions of the end effector 240, 340, 440 are outside one or more defined virtual boundaries (Boundaries 1, 2, 3, 4) and / or alert zones (Zones 1, 2, 3, 4). Therefore, no alert is necessary to notify the surgeon of potential contact with critical anatomical structures. However, as determined by the surgical navigation system 100, the surgical instrument 220, 320, 420 is not aligned with the target trajectory axis -T. In this exemplary scenario, the surgical navigation system 100 can be configured to trigger one of the various alerts described above. For example, because the orientation of the end effector 240, 340, 440 is not aligned with the target trajectory axis -T, the surgical navigation system 100 can be configured to send a signal to the instrument processor 215, 315, 415 to activate the alert device 255, 355, 455. The alert device 255, 355, 455 can be configured to provide a tactile alert A, such as vibrating the switch 250, 350, 450, depending on the type of alert assigned to the target trajectory axis -T. Alternatively, the alert device 255, 355, 455 can be configured to provide a visual alert B, such as a flashing light. In yet another configuration, the alert device 255, 355, 455 can be configured to provide an audible alert C, such as a beep. The surgical navigation system 100 can also be configured to send a signal to the instrument processor 215, 315, 415 to reduce the power of the motor 245, 345, 445 of the surgical instrument 220, 320, 420, thereby slowing the rotation of the end effector 240, 340, 440 from a maximum cutting speed to a minimum cutting speed. Alternatively, the surgical navigation system 100 can be configured to disable or stop rotation of the end effector 240, 340, 440 until the end effector 240, 340, 440 is aligned with the target trajectory axis -T, thereby preventing the end effector 240, 340, 440 from drilling a misaligned hole. It is further contemplated that various combinations of alerts can be used, such as the alert device 255, 355, 455 generating a combination of tactile alert A, visual alert B, and audible alert C.5A, the surgeon receives a tactile alert A, such as a vibrating switch 250, 350, 450, when the end effector 240, 340, 440 is not aligned with the target trajectory, axis -T. Additionally, in this scenario, it is contemplated that one or more of the various alerts described above may be assigned to notify the surgeon when the end effector 240, 340, 440 is adjacent to and / or distal to one of the virtual boundaries (Boundaries 1, 2, 3, 4) and / or when it approaches and / or enters one of the various alert zones (Zones 1, 2, 3, 4).

[0104] And, it is contemplated that the surgical navigation system 100 can be configured to simply activate the alert device 255, 355, 455 to generate one of the various alerts described above and / or send a signal to stop and disable the variable speed motor 245, 345, 445 to prevent activation of the end effector 240, 340, 440 when the end effector 240, 340, 440 and / or surgical instrument 220, 320, 420 is located within a threshold distance of the patient and / or surgical site. This may be measured relative to a reference position RL and / or a reference coordinate system defined in a known coordinate system, such as a position on a bone. By calculating the distance between the reference position and the end effector, the navigation system can determine whether the surgical instrument is relatively close to the surgical site.

[0105] Alternatively, the surgical navigation system 100 can be configured to allow the variable speed motor 245, 345, 445 to continuously drive the end effector 240, 340, 440 and / or surgical instrument 220, 320, 420 when the end effector 240, 340, 440 and / or surgical instrument 220, 320, 420 is outside a threshold distance, i.e., a safe distance, from the patient and / or surgical site, regardless of the position of the end effector 240, 340, 440 and / or surgical instrument 220, 320, 420 relative to the desired trajectory axis -T. This may include disabling all of the alert devices 255, 355, 455 when the end effector 240, 340, 440 and / or surgical instrument 220, 320, 420 is outside the threshold distance from the patient and / or surgical site. This allows a medical professional to approach the surgical site and inspect the surgical instrument 220, 320, 420 without stopping to ensure everything is in proper operating order before beginning surgery. However, once the end effector 240, 340, 440 and / or surgical instrument 220, 320, 420 comes within a threshold distance of the reference position / reference frame, activating the alert device 255, 355, 455, the surgical navigation system 100 can again communicate all appropriate signals to the processor 215, 315, 415 to activate the alert device 255, 355, 455 and / or stop the variable speed motor 245, 345, 445 in the manner described above.

[0106] 5B, a surgical instrument 220, 320, 420, such as first surgical instrument 220, is shown in a second position relative to the patient's surgical site 30. In the second position, the end effector 240, 340, 440 is spaced apart from the virtual boundary (Boundaries 1, 2, 3, 4) and / or is outside the defined alert zones (Zones 1, 2, 3, 4). Additionally, the end effector 240, 340, 440 is properly aligned with the target trajectory, axis -T. In this example scenario, the surgical navigation system 100 may determine that the end effector 240, 340, 440 is spaced (away) from one or more virtual boundaries (Boundaries 1, 2, 3, 4) and / or outside one or more predefined alert zones (Zones 1, 2, 3, 4) and aligned with the target trajectory, axis T, and may operate the switch 250, 350, 450 to actuate the end effector 240, 340, 440, allowing the surgical instrument 220, 320, 420 to operate in normal working conditions. The alert device 255, 355, 455 may also be deactivated in this scenario.

[0107] 5C, a surgical instrument 220, 320, 420, such as the third surgical instrument 220, is shown in a third position relative to the patient's surgical site 30. In the second position, the end effector 240, 340, 440 is spaced from one or more of the imaginary boundaries (Boundaries 1, 2, 3, 4) and / or is outside one or more of the defined alert zones (Zones 1, 2, 3, 4). Additionally, the end effector 240, 340, 440 is properly aligned with the target trajectory, Axis -T. However, the tip of the end effector 240, 340, 440 reaches the target depth T at or adjacent to Boundary 5. In this example scenario, the surgical navigation system 100 can be configured to determine when the end effector 240, 340, 440 or implant 275 has reached the target depth T and, since the end effector 240, 340, 440 has reached the target depth T, disable or stop rotation of the end effector 240, 340, 440 to prevent the end effector 240, 340, 440 from drilling deeper than the target depth T. The surgical navigation system can also be configured to trigger one of the various alerts described above. For example, since the end effector 240, 340, 440 has reached the target depth T, the surgical navigation system 100 can be configured to send a signal to the instrument processor 215, 315, 415 to activate an alert device 255, 355, 455. Depending on the type of alert assigned to the target position T, the alert device 255, 355, 455 can be configured to provide a tactile alert A, such as vibrating a switch 250, 350, 450, when the surgical navigation system 100 determines that the end effector 240, 340, 440 has reached the target position T. Alternatively, the alert device 255, 355, 455 can be configured to provide a visual alert B, such as a flashing light. In yet another configuration, the alert device 255, 355, 455 can be configured to provide an audible alert C, such as a beep.The surgical navigation system 100 can also be configured to send a signal to the instrument processor 215, 315, 415 to reduce the power of the motor 245, 345, 445 of the surgical instrument 220, 320, 420, thereby decreasing the rotation of the end effector 240, 340, 440 from a maximum cutting speed to a minimum cutting speed. It is further contemplated that various combinations of alerts can be used, such as the alert device 255, 355, 455 generating a combination of tactile alert A, visual alert B, and audible alert C. As shown in FIGURE 5A, the surgeon receives visual alert B, such as a flashing light on the switch 250, 350, 450, when the end effector 240, 340, 440 reaches the target depth T.

[0108] Referring to Figures 5D-5F, surgical instruments 220, 320, 420, such as first surgical instrument 220, are illustrated relative to a surgical site 30 on a patient. As described above with respect to Figures 5A-5C, the first surgical instrument 220 may be configured to operate in a similar manner relative to defined boundaries. However, Figures 5D-5F illustrate several additional exemplary virtual boundaries (boundaries 4, 5, 6, and 7) and / or alert zones. For example, Figure 5D illustrates various additional exemplary virtual boundaries (boundaries 4, 5, 6, and 7). The virtual boundaries (boundaries 4, 5, 6, and 7) may correspond to various depths for inserting different end effectors 240 coupled to the first surgical instrument 220. It is contemplated that multiple different end effectors 240, described in more detail below, may be coupled to the handpiece 225 of the first surgical instrument 220. Each of the different end effectors 240 may be configured to perform different functions and / or operations as part of a surgical procedure on a patient. The surgical navigation system 100 can be configured to identify the end effectors 240 coupled to the handpiece 225 and define corresponding virtual boundaries (boundaries 4, 5, 6, and 7) and / or alert zones for each of the end effectors 240A, 240B, and 240C. The fourth virtual boundary, boundary 4, can correspond to the target depth of the selected implant 275. The fourth, fifth, and sixth virtual boundaries (boundaries 5, 6, and 7) can be configured to correspond to the target depth of each of the end effectors 240A, 240B, and 240C, respectively. The virtual boundaries (boundaries 5, 6, and 7) for each of the end effectors 240A, 240B, and 240C, respectively, can be determined as a predetermined distance from the fourth virtual boundary, boundary 4, based on the desired depth and / or position of the corresponding end effector 240A, 240B, and 240C. It is also contemplated that the fourth virtual boundary, boundary 4, and the fifth virtual boundary, boundary 5, can be located at the same position. In this scenario, the fifth virtual boundary, boundary 5, corresponding to the first end effector 240A defines the initial target depth of the implant 275, and the next virtual boundaries (boundaries 6 and 7) can each be defined based on their distance from the fifth virtual boundary, boundary 5.For example, first end effector 240A can include a drill, second end effector 240B can include a tap, and third end effector 240C can include a driver used in a surgical procedure to prepare and insert pedicle screws into vertebrae. As shown in FIG. 5D , a fifth imaginary boundary (boundary 5) may be defined by surgical navigation system 100 to correspond to the depth of first end effector 240A, a sixth imaginary boundary (boundary 6) may be defined by surgical navigation system 100 to correspond to the depth of second end effector 240B, and a seventh imaginary boundary (boundary 7) may be defined by surgical navigation system 100 to correspond to the depth of third end effector 240C. Each of the imaginary boundaries (boundaries 4, 5, 6, and 7) can have a plane perpendicular to an axial position along axis -T, which is a target axis corresponding to the target depth of the attached end effector 240A, 240B, or 240C. The navigation system 100 may be configured to define virtual boundaries (boundaries 4, 5, 6, 7) based on the position of the surgical instrument and the known position of the tip of each end effector 240A, 240B, 240C coupled to the handpiece 225.

[0109] One or more of the various alerts and / or alert devices 255, 355, 455 described above may be assigned to each of the various virtual boundaries (boundaries 4, 5, 6, 7). While the virtual boundaries (boundaries 4, 5, 6, 7) have been described as being defined by the surgical navigation system 100, it is contemplated that they may be defined and / or selected by a medical professional. For example, a medical professional may define or select a virtual boundary (boundary 4, 5, 6, 7) within the patient data using the user input device 130 or the graphical user interface (GUI) 150. Furthermore, while the virtual boundaries (boundaries 4, 5, 6, 7) may be defined and / or recommended by the surgical navigation system 100, it is also contemplated that a medical professional may modify or change a virtual boundary (boundary 4, 5, 6, 7) defined by the surgical navigation system 100 using the user input device 130 and / or the graphical user interface (GUI) 150.

[0110] Referring to FIG. 5E, surgical instruments 220, 320, 420, such as first surgical instrument 220, are illustrated relative to a surgical site 30 on a patient. As described above with respect to FIGS. 5A-5C, first surgical instrument 220 may be configured to operate in a similar manner relative to defined alert zones. FIG. 5E illustrates alternative exemplary configurations of alert zones (Zones 5 and 6). As described above, alert zones can be defined around or abutting critical anatomical structures, such as Zones 1, 2, and 3 shown in FIGS. 4A-5C, to alert a medical professional when critical anatomical structures are being approached. Additionally, alert zones can be defined to identify boundaries of anatomical structures, such as Zone 4 shown in FIGS. 5A-5D, to alert a medical professional when the boundary is being approached and to avoid breaching the cortical wall. As shown in FIG. 5E, alert zones (Zones 5 and 6) can be defined along the opposing boundaries of a target trajectory, Axis-T, to alert a medical professional of any deviation from the target trajectory, Axis-T. The alert zones (Zones 5 and 6) can also be shaped or contoured to match the shape of critical anatomical structures and / or boundaries. For example, the surgical navigation system 100 can be configured to define an alert zone (Zone 6) that is curved around the periphery of a vertebra to alert a medical professional to prevent the medical professional from breaking through the periphery of the pedicle when the end effector 240 of the first surgical instrument 220 is approaching the periphery of the vertebra. Furthermore, the surgical navigation system 100 can be configured to define an alert zone (Zone 5) that is contoured around a critical anatomical structure (central foramen) within a vertebra to alert a medical professional to prevent the medical professional from contacting the critical anatomical structure when the end effector 240 of the first surgical instrument 220 is approaching the critical anatomical structure.

[0111] Referring to FIG. 5F, surgical instruments 220, 320, 420, such as first surgical instrument 220, are illustrated relative to a surgical site 30 on a patient. The virtual boundaries (boundaries 4, 5, 6, and 7) are the same as those described above with respect to FIG. 5D. However, the system of FIG. 5F illustrates an alternative arrangement of components, in which the surgical instrument also includes a battery module 260, which includes a battery processor 265. The system can be configured such that navigation processor 140 is in communication with battery processor 265. Battery processor 265 can receive signals from navigation processor 140 to manipulate the flow of power from battery module 260 to handpiece 225 and, therefore, variable speed motor 245, based on the position of the surgical instrument relative to the virtual boundaries (boundaries 4, 5, 6, and 7). The signal from navigation processor 140 can be configured to indicate to battery processor 265 that the position of end effector 240 is adjacent and / or distal to a virtual boundary (boundaries 4, 5, 6, 7), causing battery processor 265 to discontinue the flow of power from battery module 260 to hand piece 225 and thus variable speed motor 245. Alternatively, it is contemplated that based on the navigation system 100 determining that the position of end effector 240 is adjacent and / or distal to a virtual boundary (boundaries 4, 5, 6, 7), the signal from navigation processor 140 can include a command to battery processor 265 instructing battery processor 265 to discontinue the flow of power from battery module 260 to hand piece 225 and thus variable speed motor 245. Additionally, battery processor 265 can be in communication with tool processor 215, and tool processor 215 can be configured to stop the motor based on data received from the battery processor.

[0112] Referring to FIG. 6, an exemplary configuration of a surgical system including the above-described surgical navigation system 100 and a first surgical instrument 220 is illustrated. While only the first surgical instrument is illustrated in FIG. 6, it is contemplated that any of the above-described surgical instruments 220, 320, 420 may be included in the system. The surgical system may also include multiple end effectors 240A, 240B, 240C that detachably couple to the handpiece 225 of the first surgical instrument 220. The end effectors 240A, 240B, 240C may also be referred to as end effectors, surgical attachments, and / or instrument attachments. For example, the surgical system may include a first end effector 240A that includes a drill for cutting biological material and / or drilling holes. The surgical system may also include a second end effector 240B that includes a tap for forming threads on the inner surface of a hole or opening. The surgical system may also include a third end effector 240C that includes a driver for driving or inserting a screw into a hole or opening. Each end effector 240A, 240B, 240C may have an instrument tracking device 230A, 230B, 230C with a unique configuration and / or arrangement of markers 235A, 235B, 235C. For example, the markers 235A, 235B, 235C of an instrument tracking device 230A, 230B, 230C may include a unique size, shape, and / or arrangement relative to the markers 235A, 235B, 235C of the other instrument tracking devices 230A, 230B, 230C. Although not shown, it is also contemplated that each of the end effectors 240A, 240B, 240C can be coupled to a separate hand piece 225, and each of the hand pieces 225 can have a tracking device 230A, 230B, 230C with a unique configuration and / or arrangement of markers 235A, 235B, 235C. For example, the markers 235A, 235B, 235C of an instrument tracking device 230A, 230B, 230C can include a unique size, shape, and / or location relative to the markers 235A, 235B, 235C of the other instrument tracking devices 230A, 230B, 230C.The navigation system 100 can be configured to identify the end effectors 240A, 240B, 240C based on their known association with a particular hand piece 225 and the specific size, shape, and / or placement relative to the markers 235A, 235B, 235C of the instrument tracking devices 230A, 230B, 230C attached to the particular hand piece 225. The navigation system may then be configured to provide virtual boundaries (boundaries 4, 5, 6, 7) and / or alert zones (zones 4, 5, 6, 7) of the appropriate end effector 240A, 240B, 240C currently being navigated.

[0113] The surgical navigation system 100 can be configured to identify which end effector 240A, 240B, 240C is coupled to the first surgical instrument handpiece 225 based on the placement and / or configuration of the markers 235A, 235B, 235C of the instrument tracking devices 230A, 230B, 230C. The surgical navigation system 100 may then be configured to define various alert zones. For example, the surgical navigation system 100 may be configured to define alert zones and / or boundaries corresponding to target depths for each of the individual end effectors 240A, 240B, 240C. An exemplary configuration of virtual boundaries (boundaries 4, 5, 6, and 7) and / or alert zones, zones 5, 6, and 7, is shown in Figure 5D, where boundary 5 may correspond to a target depth for first end effector 240A, boundary 6 may correspond to a target depth for second end effector 240B, and boundary 7 may correspond to a target depth for third end effector 240C. The surgical navigation system 100 can be programmed and / or configured to manipulate the speed of a motor 245, 345, 445 of a surgical instrument 220, 320, 420 and / or activate an alert device 255, 355, 455 when the surgical navigation system 100 determines that a surgical instrument 220, 320, 420 is at or adjacent to one or more of the virtual boundaries (boundaries 4, 5, 6, and 7) or has entered one of the predefined alert zones. For example, when the surgical navigation system 100 detects that the first end effector 240A is coupled to the handpiece 225, the surgical navigation system 100 may be configured to send a signal to the processor 215, 315, 415 of the surgical instrument 220 to stop the variable speed motor 245, 345, 445 when the first end effector 240A is adjacent to and / or distal to the boundary 5.When the surgical navigation system 100 detects that the second end effector 240B is coupled to the handpiece 225, the surgical navigation system 100 may be configured to send a signal to the processor 215, 315, 415 of the surgical instrument 220 to stop the variable speed motor 245, 345, 445 when the second end effector 240B is adjacent to and / or distal to boundary 6. When the surgical navigation system 100 detects that the third end effector 240C is coupled to the handpiece 225, the surgical navigation system 100 may be configured to send a signal to the processor 215, 315, 415 of the surgical instrument 220 to stop the variable speed motor 245, 345, 445 when the third end effector 240C is adjacent to and / or distal to boundary 7. In other words, only certain alert zones and / or virtual boundaries are enabled for certain end effectors. When the appropriate end effector enters the surgical field, the surgical navigation system activates only the appropriate virtual boundary and / or alert zone appropriate for the identified end effector.

[0114] When the end effector 240, 340, 440 becomes adjacent to and / or distal to one of the virtual boundaries and / or enters one of the various alert zones, the surgical navigation system 100 sends a signal to the processor 215, 315, 415 of the surgical instrument 220, 320, 420 to stop the variable speed motor 245, 345, 445, which causes the processor 215, 315, 415 to stop the variable speed motor 245, 345, 445, such as by rotating the motor at 0 rpm. The processor 215, 315, 415 can be configured to temporarily stop the variable speed motor 245, 345, 445 and then restart the variable speed motor 245, 345, 445 while the end effector 240, 340, 440 remains adjacent to and / or distal to one of the virtual boundaries and / or within one of the various alert zones. The variable speed motor 245, 345, 445 can be restarted by the processor 215, 315, 415 after a predetermined period of time, such as over 1 second, 2 seconds, 3 seconds, 4 seconds, etc.

[0115] Alternatively, the variable speed motor 245, 345, 445 may be restarted by the processor 215, 315, 415 after the processor 215, 315, 415 receives a signal indicating that the switch 250, 350, 450 has been operated by a user. For example, the processor may analyze a series of switch operations within a predetermined period of time. For example, the processor 215, 315, 415 may be configured to restart the variable speed motor 245, 345, 445 after receiving a signal from a switch sensor indicating that the switch 250, 350, 450 has been operated between the second position and the first position and back to the second position within half a second. The times and number of times the switch 250, 350, 450 is intended only as an example cadence and / or time frame for operating the switch 250, 350, 450 to restart the variable speed motor 245, 345, 445 after the variable speed motor 245, 345, 445 has stalled due to entering an alert zone. In one example, the processor 215, 315, 415 may restart the motor 245, 345, 445 when the trigger or footswitch 250, 350, 450 is fully released.

[0116] Once the motor 245, 345, 445 has been restarted, control of the speed of the end effector 240, 340, 440 can be performed by operation of the switch or trigger 250, 350, 450, as in normal operation.

[0117] When the variable speed motor 245, 345, 445 is restarted while the end effector 240, 340, 440 is adjacent to and / or distal to one of the virtual boundaries and / or still remains within one of the various alert zones, the surgical navigation system 100 continues to track the position of the end effector 240, 340, 440 and / or surgical instrument 220, 320, 420.

[0118] However, after restart, if the surgical navigation system 100 detects that the end effector 240, 340, 440 and / or surgical instrument 220, 320, 420 has moved further distally relative to the boundary and / or further into the alert zone, or has moved a threshold distance distally relative to the boundary and / or has passed through a portion of the alert zone, the surgical navigation system 100 can be configured to send a subsequent signal to the processor 215, 315, 415 to again operate the speed and / or stop the variable speed motor 245, 345, 445. For example, if the surgical navigation system 100 detects that the end effector 240, 340, 440 has moved 2 millimeters distal to the virtual boundary and / or further into the alert zone, the surgical navigation system 100 can be configured to send a subsequent signal to the processor 215, 315, 415 to restart the variable speed motor 245, 345, 445. The surgeon must then go through one of the processes described above again to restart the variable speed motor 245, 345, 445. The navigation processor 140 and / or instrument processor 215, 315, 415 can be configured to allow only a limited number of restarts and / or to allow restarts only when the end effector 240, 340, 440 is within a threshold distance of a boundary and / or zone.

[0119] Alternatively, if the variable speed motor 245, 345, 445 is restarted while the end effector 240, 340, 440 is adjacent and / or distal to one of the virtual boundaries and / or while still within one of the various alert zones, the surgical navigation system 100 can be configured to allow the variable speed motor 245, 345, 445 to operate uninterrupted if the surgical navigation system 100 determines that the end effector 240, 340, 440 is moving proximally relative to the virtual boundaries and / or is being pulled out of the alert zone. That is, if the navigation system 100 determines that the end effector 240, 340, 440 is being inverted, the navigation processor 140 and / or instrument processor 215, 315, 415 can be configured to allow normal operation of the surgical instrument 220, 320, 420.

[0120] The first surgical instrument 220 can also include a mode switch 270 configured to change the operating characteristics of the variable speed motor 245. The switch may be configured to be slidable and / or rotatable between two or more positions. For example, if there are first and second positions, the mode switch may be configured to switch the variable speed motor between a high speed and a low speed based on the position of the mode switch. Alternatively, the mode switch may be configured to switch the variable speed motor between a high torque mode and a low torque mode of operation based on the position of the mode switch. In yet another configuration, the mode switch may be configured to switch the variable speed motor between a high speed, low torque mode of operation and a low speed, high torque mode of operation based on the position of the mode switch. The operating mode can be selected by a medical professional depending on the type of treatment to be performed. For example, when performing drilling, the medical professional may want the surgical instrument 220 to be in a high speed, low torque mode of operation. Alternatively, when performing driving, the medical professional may want the surgical instrument 220 to be in a low speed, high torque mode of operation.

[0121] The surgical navigation system 100 may also be configured to determine the position of the mode switch 270. The surgical instrument 220 may include a mode switch sensor that detects the position of the mode switch 270. The processor 215 may then be configured to communicate the position of the mode switch to the surgical navigation system 100. Alternatively, the mode switch may include a tracking device that enables the surgical navigation system 100 to determine the position of the mode switch 270. Alternatively, the surgical navigation system 100 may be configured to determine the position of the mode switch 270 using machine vision. As noted above, the surgical navigation system may also be configured to determine which of multiple end effectors 240A, 240B, 240C is coupled to the handpiece 225 of the surgical instrument 220. As noted above, certain operating modes may be advantageous for different procedures. Therefore, the surgical navigation system 100 may be configured to compare the end effectors 240A, 240B, 240C to an operating mode based on the determined position of the mode switch 270. The surgical navigation system 100 can then be configured to send a signal to the processor 215, 265 of the surgical instrument 220 to prevent operation of the handpiece 225 if the position of the mode switch 270 does not match the preferred mode of operation of the end effectors 240A, 240B, 240C coupled to the handpiece 225. For example, if a drill-type end effector 240A is coupled to the handpiece 225 and the preferred mode of operation is high speed, low torque, and the mode switch 270 is in the low speed, high torque position, the surgical navigation system 100 can be configured to send a signal to the processor 215, 265 to prevent the processor 215, 265 from energizing the variable speed motor 245 until the mode switch 270 is moved to the high speed, low torque position.

[0122] Referring to FIG. 7, an exemplary configuration of a surgical system including the above-described surgical navigation system 100 and a second surgical instrument 320 is illustrated. While FIG. 6 illustrates only the first surgical instrument, it is contemplated that any of the above-described surgical instruments 220, 320, and 420 may be included in the system. The surgical system may also include multiple end effectors 340A, 340B, and 340C that detachably couple to the handpiece 325 of the second surgical instrument 320. The end effectors 340A, 340B, and 340C may also be referred to as end effectors, surgical attachments, and / or instrument attachments. For example, the surgical system may include a first end effector 340A including a first burr head 360A having a first diameter head D1. The surgical system may further include a second end effector 340B including a second burr head 360B having a second diameter head D2. Additionally, the surgical system can also include a third end effector 340A including a third burr head 360C having a first diameter head D3. It is contemplated that the heads of each end effector 340A, 340B, 340C may vary in shape, material, and / or cutting type. It is also contemplated that the shaft length may vary from one end effector 340A, 340B, 340C to the next.

[0123] The surgical navigation system 100 can also be configured to identify which of the end effectors 340A, 340B, 340C is coupled to the handpiece 325. One exemplary method for identifying which end effectors 340A, 340B, 340C are coupled to the handpiece 325 is to use machine vision. In this exemplary configuration, the surgical navigation system 100 can be configured to identify which end effectors 340A, 340B, 340C are coupled to the handpiece 325 based on the respective characteristics of the various end effectors 340A, 340B, 340C. For example, the surgical navigation system 100 can be configured to identify the end effectors 340A, 340B, 340C based on the diameters D1, D2, D3 of the heads 360A, 360B, 360C. The surgical navigation system 100 can then be configured to define various alert zones based on the identified end effectors 340A, 340B, 340C. For example, the surgical navigation system 100 may be configured to define alert zones around one or more critical anatomical structures. Exemplary configurations of virtual boundaries (Boundaries 1, 2, 3) and / or alert zones (Zones 1, 2, 3) are shown in FIGS. 4A-4D. The various virtual boundaries and / or alert zones can be based on different distances around a single critical anatomical structure, or multiple critical anatomical structures can be identified using one or more virtual boundaries and / or alert zones. When the surgical navigation system 100 determines that the surgical instrument 220, 320, 420 has entered one of the predefined alert zones, the surgical navigation system 100 can be programmed and / or configured to perform any of a variety of alert types, such as stopping the surgical instrument 220, 320, 420 or activating an alert device 255, 355, 455. For example, different diameter end effectors may have different alert zone thicknesses. That is, the depth of the alert zone relative to critical structures and / or boundaries may be automatically adjusted and / or configured by the navigation system 100 based on the identification of the end effector 240, 340, 440.

[0124] Referring to FIG. 8 , an exemplary configuration of a graphical user interface (GUI) 150 of the navigation system 100 is illustrated. The graphical user interface (GUI) 150 may be configurable as a touchscreen on the display 120 of the navigation system 100. As shown in FIG. 8 , the graphical user interface (GUI) 150 may include a plurality of buttons and / or prompts that are selectable and / or operable by the surgeon. For example, the graphical user interface (GUI) 150 may include an exemplary alert interface 151 or window that includes a plurality of user-selectable or operable buttons to modify or adjust various settings for alerts to be provided during a medical procedure. The alert setting interface 151 may include instrument selection buttons 152A, 152B. The instrument selection buttons 152A, 152B may allow the surgeon to select a surgical instrument assembly 200, 300, 400 from a pre-populated list of surgical instruments or may allow the surgeon to input a particular surgical instrument assembly 200, 300, 400 to be utilized outside of a surgical procedure. For example, the instrument selection buttons 152A, 152B may allow the surgeon to select a second surgical instrument 320 that includes a high-speed cutting burr. This allows the particular surgical instrument 320 to be identified from the navigation system 140, so that the navigation system can input various virtual boundaries and / or alert zones to be used for the identified instrument. Additionally, the instrument selection buttons 152A, 152B may be configured to allow the surgeon to select one or more end effectors 240, 340, 440 that may be coupled to the surgical instrument assembly 200, 300, 400 and surgical instrument 220, 320, 420. For example, the surgeon may select the first surgical instrument 220 and then select one or more of the end effectors 240A, 240B, 240C that may be used during surgery, so that the navigation system can input various virtual boundaries and / or alert zones for each of the various end effectors 240A, 240B, 240C.

[0125] The alert settings interface 151 may further include one or more alert buttons 156A, 156B, 156C, 156D. The alert buttons 152A, 152B, 156C, 156D may be used to manipulate the various alerts described above. For example, the first alert button 156A may be configured to allow a user to activate or deactivate an alert related to the rotational speed of the end effector 240, 340, 440. For example, as described above, the navigation processor 140 and / or the instrument processor 215, 315, 415 may be configured to manipulate the rotational speed (RPM) of the end effector 240, 340, 440 based on the position of the end effector 240, 340, 440 relative to one or more virtual boundaries and / or alert zones.

[0126] The second alert button 156B can be configured to allow a user to activate or deactivate a tactile alert. For example, a user can actuate the second alert button 156B to activate one of the tactile alerts described above. This can include configuring the navigation processor 140 to send a signal to the surgical tool assembly 200, 300, 400 that activates an alert device 255, 355, 455 configured to provide a tactile alert to the surgeon based on the position of the end effector 240, 340, 440 relative to one or more of the virtual boundary and / or alert zones.

[0127] The third alert button 156C can be configured to allow a user to activate or deactivate a visual alert. For example, a user can actuate the third alert button 156C to activate one of the visual alerts. This can include configuring the navigation processor 140 to send a signal to the surgical tool assembly 200, 300, 400 to activate an alert device 255, 355, 455 configured to provide a visual alert to the surgeon based on the position of the end effector 240, 340, 440 relative to one or more of the virtual boundary and / or alert zones.

[0128] The fourth alert button 156D can be configured to allow a user to activate or deactivate one of the audible alarms described above. For example, a user can actuate the fourth alert button 156D to activate an audible alert, causing the navigation processor 140 to send a signal to the surgical tool assembly 200, 300, 400 to activate an alert device 255, 355, 455 configured to provide an audible alert to the surgeon based on the position of the end effector 240, 340, 440 relative to one or more of the virtual boundary and / or alert zones.

[0129] The alert setting interface 151 of the graphical user interface (GUI) 150A can also include one or more alert graphics 158A, 158B. The alert graphic(s) 154A, 154B may be specific to a particular surgical instrument and / or end effector and configured to provide a general and / or visual representation of the location of various virtual boundaries and / or alert zones. The first alert graphic 158A can include a visual representation of the surgical area and any implants or devices to be inserted during the medical procedure to assist the surgeon in locating the surgery and setting various alerts. For example, as shown in FIG. 8 , the first alert graphic includes a visual representation of a vertebral body with the area where the surgery will be performed outlined by a dotted line. The first alert graphic can further include a visual representation of a pedicle screw to be inserted during the surgery.

[0130] To facilitate the surgeon's adjustment or modification of the locations at which the alerts assigned to each of the various virtual boundaries and / or alert zones should be triggered, the second alert graphic 158B can be configured to provide a visual representation of the implant or device to be inserted during surgery, along with markers indicating the various virtual boundaries for the implant or device (boundaries 5, 6, and 7). For example, as shown in FIG. 8, the second alert graphic 158B includes a visual representation of the pedicle screw to be inserted and markers along the pedicle screw indicating the locations of the various virtual boundaries for the pedicle screw (boundaries 1, 2, and 3) that will trigger various alerts during surgery.

[0131] Additionally, the alert setting interface 151 of the graphical user interface (GUI) 150A can include virtual boundary setting interfaces 160A, 160B. The virtual boundary setting interfaces 160A, 160B can include one or more prompts or buttons 162A, 162B, 162C, 162D, 162E for setting and / or manipulating when the virtual boundary triggers one or more of the various alerts described above. The first virtual boundary setting interface 160A can include a first button 162A that can be configured to identify the implant(s) and / or device(s) to be inserted during surgery. This allows the navigation system 100 to determine which and how many virtual boundaries and / or alert zones to provide. For example, if the surgeon operates the first button 162A to indicate that they will be performing a laminotomy, the navigation system 100 will understand that this is a resection process, and the navigation system 100 will recognize, identify, and provide various alert zones around critical vertebral structures to assist the surgeon in the procedure. Alternatively, if the surgeon operates the first button 162A to indicate that they will be performing a pedicle screw procedure, the navigation system 100 will recognize, identify, and provide various virtual boundaries necessary to assist the surgeon in drilling, tapping, and placing the pedicle screws.

[0132] The second button 162B of the virtual boundary setting interface 160A can be configured to include a depth button 162B. The depth button 162B can be configured to allow the surgeon to select the depth of an alert zone for a resection procedure, such as a laminotomy. For example, the first boundary setting interface 160A shown in FIG. 8 indicates that the surgeon is setting an alert for a laminotomy based on the operation of the first button 162A. Based on this selection by the surgeon, the second button 162B provides an operable button configured to allow the surgeon to select the depth of the alert zone that the navigation system 100 should use to trigger one or more of various alerts.

[0133] The alert settings interface 151 can be configured such that the alert graphic 158A adjacent to the boundary settings interface 160A can be manipulated or changed based on manipulation of the buttons 162A, 162B of the boundary settings interface 160A.

[0134] The second boundary setting interface 160B of the alert setting interface 151 may have additional buttons 162C, 162D, and 162E associated with configuring various virtual boundaries and / or alert zones for triggering alerts during a medical procedure. For example, as shown in FIG. 8 , the second boundary setting interface 160B can be configured to provide buttons 162C, 162D, and 162E for manipulating alert settings for a procedure involving pedicle screw insertion. The third button 162C of the second boundary setting interface 160B can be configured to set the distance or depth of a reference location for placing a virtual boundary, such as boundary 5, along a target trajectory. For example, as shown in FIG. 8 , the third button 162C includes a toggle that allows the surgeon to set the depth for inserting the first end effector, i.e., drill, before an alert is triggered. As an example, a user may set the third button 162C to 30 mm, indicating that the navigation system 100 should trigger the alert when the first end effector has traveled a distance of 30 mm or reached a depth of 30 mm. The second boundary setting interface 160B may include additional buttons 162D and 162E for manipulating and / or adjusting the timing for triggering an alert for the second end effector, i.e., the tap, and / or the third end effector, i.e., the screwdriver. As described above, the navigation system 100 may be configured such that the fourth and fifth buttons 162D and 162E for manipulating the alerts for the second and third end effectors manipulate the position of the virtual boundary for triggering an alert based on the virtual boundary for triggering an alert for the first end effector. For example, as indicated by the fourth button 162D, the virtual boundary for triggering an alert for the second end effector, i.e., the tap, should be offset by 0 millimeters (0 mm) relative to the virtual boundary for triggering an alert for the first end effector. However, the fourth button 162D may be operable to shift the boundary for triggering an alert for the second end effector, as needed.Similarly, the fifth button 162E is operable to change or adjust the virtual boundary for triggering an alert for the third end effector.

[0135] The alert settings interface 151 of the graphical user interface (GUI) 150A may also include alert test buttons 164A, 164B. The alert test buttons 164A, 164B may be configured to test and / or verify that a selected alert is active and operating properly. For example, in operation, after the surgeon has selected and / or entered various information related to a medical procedure into the alert settings interface 151, the surgeon can select the alert test buttons 164A, 164B to verify that the selected alert is active. For example, if the surgeon selects the first alert button 156A instructed to activate a motor speed alert, the surgeon can activate a surgical instrument 220, 320, 420 and press the alert test button 164A, 164B. Pressing the alert test button 164A, 164B instructs the navigation system to send a test signal to the instrument processor 215, 315, 415 to activate the alert associated with the first alert button 156A, such as slowing down the motor speed and therefore the rotational speed of the end effector 240, 340, 440. When the user selects the alert test button 164A, 164B, each of the various alerts activated based on the operation of the alert buttons 156A, 156B, 156C, 156D, 156E should trigger. Activated alerts that are not triggered upon selection of the alert test button 164A, 164B should be further evaluated by the surgeon to ensure they are, in fact, operating properly before beginning the medical procedure.

[0136] Referring to FIG. 9, an exemplary graphical user interface (GUI) 150B is shown on the display 120 of the navigation system 100. The graphical user interface (GUI) 150B can be configured to include a visual representation of the surgical plan, including the planned orientation of the implants 275A and 275B within a known coordinate system. The implants 275A and 275B may define target axes T1 and T2. As described above, the navigation system 100 may provide one or more virtual boundaries (boundaries 5, 6, and 7) along the target axes T1 and T2 that represent target depths for each of the various end effectors 240A, 240B, and 240C used in the surgery. For example, as shown in FIG. 9, first boundaries (boundaries 5A and 5B) are shown for each of the implants 275A and 275B along the target axes T1 and T2. The navigation system 140 can be configured to define a first boundary (boundaries 5A, 5B) based on a target depth for the tip of the first end effector 240A, such as a drill to drill holes for placing the screws 275A, 275B. The navigation system 100 can further be configured to define a second boundary (boundaries 6A, 6B) based on a target depth for the second end effector 240C, such as a tap to thread the holes. It is also contemplated that the navigation system 100 can define a second boundary (boundaries 6A, 6B) relative to the first boundary (boundaries 5A, 5B) based at least in part on the selected implants 275A, 275B and their orientations. For example, the navigation system 100 can define the first boundary (boundaries 5A, 5B) within the patient's known coordinate system along target axes T1 and T2. Next, based on the selected implants 275A, 275B, the navigation system 100 can be configured to define a second boundary (boundaries 6A, 6B) spaced apart from the first boundary (boundaries 5A, 5B) based on the selected implants 275A, 275B. Additionally, the navigation system 140 can be configured to define a third boundary (boundaries 7A, 7B) based on a target depth of a third end effector 240C, such as a driver, for driving screws 275A, 275B into the holes.It is also contemplated that the navigation system 100 can define a third boundary (boundaries 7A, 7B) relative to the first boundary (boundaries 5A, 5B) based at least in part on the selected implants 275A, 275B and their orientations. For example, the navigation system 100 can define the first boundary (boundaries 5A, 5B) in a known coordinate system of the patient along target axes T1 and T2. Then, based on the selected implants 275A, 275B, the navigation system can be configured to define a third boundary (boundaries 7A, 7B) spaced apart from the first boundary (boundaries 5A, 5B) based on the selected implants 275A, 275B. For example, the navigation system may be configured such that, based on the depth of the first boundaries (boundaries 1A and 1B) and the known lengths of the selected implants 275A and 275B, the navigation system can determine that the third boundaries (boundaries 7A and 7B) should be 30 millimeters (mm) away from the first boundaries (boundaries 5A and 5B) along target axes T1 and T2. While FIG. 9 illustrates only the first boundaries (boundaries 5A and 5B), the second boundaries (boundaries 6A and 6B), and the third boundaries (boundaries 7A and 7B), additional virtual boundaries are contemplated. The navigation system 140 may be configured to define and assign virtual boundaries to each of the end effectors 240A, 240B, and 240C. The location of these virtual boundaries and / or when they are configured to trigger one of the various alerts described above can be manipulated and / or adjusted in the manner described with respect to FIG. 8 for the alert setting interface 151.

[0137] 9 may also include a planning interface 166A that includes a plurality of planning buttons 168A, 168B that the surgeon can operate to modify or adapt the placement of the implants 275A, 275B. For example, the planning interface 166A may include a diameter button that the surgeon can operate to change the diameter of the planned screws. Additionally, the planning interface 166A may include a length button that the surgeon can operate to change the length of the planned screws 275A, 275B. Using the planning interface 166A, the user can reposition the planned screws 275A, 275B by changing their position and / or orientation relative to the patient model.

[0138] The planning interface 166A of the graphical user interface (GUI) 150B of FIG. 9 may further include an alert button 170. As noted above, the alert button 170 may be configured to activate, modify, and / or disable one or more of the various alerts described above. The graphical user interface (GUI) 150B may be configured such that, when the surgeon selects the alert button 170, the surgeon can open a boundary setting interface 160C similar to that described in FIG. 8. The boundary setting interface 160C may include additional buttons and / or prompts that the surgeon can operate to change or adjust the virtual boundary and / or alert zones configured to trigger one or more alerts.

[0139] Referring to FIG. 10 , an exemplary boundary setting interface 160C is illustrated as it may be viewed by the surgeon upon selection of an alert button 170. For example, a user selecting the alert button 170 of the planning interface 166A from the graphical user interface (GUI) 150B from FIG. 9 can cause the graphical user interface (GUI) 150B to open the boundary setting interface 160C for display on the navigation display 120. The boundary setting interface 160C may include an alert button 156D configured to allow the surgeon to activate or deactivate various alerts. Additionally, the boundary setting interface 160C may include one or more buttons 162C, 162D, 162E similar to those described for the boundary setting interfaces 160A, 160B of FIG. 8 above. For example, the boundary setting interface 160C may include three boundary operation buttons 162C, 162D, 162E, one for each of the various end effectors 240A, 240B, 240C. As described above, operation of buttons 162C, 162D, and 162E can change or manipulate when alerts are triggered for each of the various end effectors 240A, 240B, and 240C. This allows the surgeon to create a custom surgical plan by modifying the navigation system 100. Based on the values entered by the surgeon using buttons 162C, 162D, and 162E, the positions of the various virtual boundaries will be updated within the surgical plan used to navigate the system to trigger alert(s) based on the positions of the various end effectors 240A, 240B, and 240C relative to one or more virtual boundaries during surgery.

[0140] The graphical user interface (GUI) 150B may even include level labels 174 that are displayed on the display 120 of the navigation system 100. The level labels 174 may be configured to identify anatomical features or significant structures. For example, as shown in FIGS. 9 and 10 , the level label 174 is configured to identify the third lumbar vertebra (L3). The level labels 174 may be used to identify any number of anatomical structures and / or regions of the patient. Alternatively, the level labels 174 may be used to identify a particular posture, orientation, or view of the displayed anatomical structure. The level labels 174 may be automatically assigned by the navigation system based on patient data. Alternatively, the level labels 174 may be selected by the surgeon from a pre-populated list. For example, the patient data may include images or representations of the patient's spine, and the surgeon may select level labels 174 assigned to each of the vertebrae. In yet another configuration, the navigation system 100 may be configured to allow the surgeon to input the level labels 174 using the user input device 130 or the graphical user interface (GUI) 150.

[0141] 11A-11C, an alternative exemplary graphical user interface (GUI) 150C shown on the display 120 of the navigation system 100 is illustrated. The graphical user interface (GUI) 150C can be configured to display multiple views of the anatomical feature, including various virtual boundaries (boundaries 1, 2, 8, 9) and / or alert zones (zone 1) depicted in a known coordinate system relative to the anatomical feature for the resection procedure. Referring to FIG. 11A, a top view of the vertebrae is displayed in the graphical user interface (GUI) 150C, including the locations of the various virtual boundaries (boundaries 1, 2, 8, 9) and / or alert zones (zone 1) relative to key anatomical structures. Similar to the graphical user interface (GUI) 150 described above, the graphical user interface (GUI) 150C illustrated in FIG. 11A includes a planning interface 166B having one or more buttons, such as an alert button 156D, configured to activate and / or deactivate one or more of various alerts. Additionally, planning interface 166B may also have a planning button 168C configured to allow the surgeon to manipulate various alerts configured to trigger one or more various alerts and / or various virtual boundaries (Boundaries 1, 2, 8, 9). For example, planning button 168C of planning interface 166B may be configurable to allow the user to increase or decrease the depth of one or more of the various alert zones by manipulating the distance between one or more virtual boundaries (Boundaries 1, 2) that define at least a portion of the alert zone (Zone 1).

[0142] Additionally, the graphical user interface (GUI) 150C may include alert indicators 172 positioned within the display of the anatomical features for various virtual boundaries (Boundaries 1, 2, 8, and 9) and / or alert zones (Zone 1). The alert indicators 172 may be positioned proximate a particular virtual boundary (Boundaries 1, 2, 8, and 9) and / or alert zone (Zone 1) and configured to allow the surgeon to identify whether an alert assigned to the boundary (Boundaries 1, 2, 8, and 9) and / or alert zone (Zone 1) proximate the alert button is activated, deactivated, and / or snoozed. For example, the alert indicator 172 proximate the fourth boundary, Boundary 4, displays a bell with a line through it. The navigation system 140 may be configured so that this symbol indicates that the alert for the fourth boundary, Boundary 4, is deactivated. Alternatively, the alert indicators 172 proximate the first and second boundaries (Boundaries 1 and 2) display a bell with no line through it. The navigation system 140 may be configured such that the alert indicators 172 indicate that alerts for the first and second boundaries, Boundaries 1 and 2, have been activated. The alert indicators 172 may also be selectable and / or operable by the surgeon to activate or deactivate alerts assigned to particular virtual boundaries (Boundaries 1, 2, 8, and 9) and / or alert zones (Zone 1). For example, the alert indicator 172 proximate to the fourth boundary, Boundary 4, may be configured to allow the surgeon to activate or deactivate the alert for the fourth boundary, Boundary 4, by manipulating the alert indicator 172.

[0143] 11B, a lateral view of the vertebrae is displayed in a graphical user interface (GUI) 150C, including the locations of various virtual boundaries (Boundaries 1, 2, 8, and 9). Although not shown in FIG. 11B, it is also contemplated that the graphical user interface (GUI) 150 of FIG. 11B may further include a planning interface 166 having one or more buttons 168 configured to enable the surgeon to manipulate various alerts and / or the locations of various virtual boundaries (Boundaries 1, 2, 8, and 9) and / or the location of an alert zone (Zone 1) that can be defined to trigger various alerts. Furthermore, the graphical user interface (GUI) 150C may also include alert indicators 172 positioned within the display of the anatomical shape for the various virtual boundaries (Boundaries 1, 2, 8, and 9) and / or alert zone (Zone 1). The alert indicators 172 can be positioned proximate particular virtual boundaries (Boundaries 1, 2, 8, 9) and / or alert zones (Zone 1) and can be further manipulated by the surgeon to activate, deactivate, and / or snooze alerts assigned to particular virtual boundaries (Boundaries 1, 2, 8, 9) and / or alert zones (Zone 1). For example, an alert button proximate the fourth boundary, Boundary 4, can be configured to enable the surgeon to activate or deactivate an alert associated with the fourth boundary, Boundary 4, by manipulating the alert indicator 172. As described above, the alert indicators 172 can be further configured to allow the surgeon to identify whether an alert assigned to a boundary (Boundary 1, 2, 8, 9) and / or alert zone (Zone 1) proximate the alert indicator 172 has been activated or deactivated.

[0144] Additionally, the graphical user interface (GUI) 150C can include one or more labels 174A, 174B that identify the anatomical structures displayed on the graphical user interface (GUI) 150C. As shown in FIG. 11C , two labels 174A, 174B are displayed on the graphical user interface (GUI) 150C, with a first label 174A identifying a primary anatomical structure and a second label 174B identifying an adjacent anatomical structure. The graphical user interface (GUI) 150C can be configured to allow a user to navigate between the primary anatomical structure and the adjacent anatomical structure by manipulating the graphical user interface (GUI) 150C. For example, the surgeon can select the first label 174A, which identifies the anatomical structure adjacent to the first label 174A as the primary anatomical structure. The graphical user interface (GUI) 150C can be configured to display the primary anatomical structure in the center of the display 120. Alternatively, the surgeon may select second label 174B and can configure graphical user interface (GUI) 150C to identify the anatomical structure adjacent second label 174B as the primary anatomical structure and center the anatomical structure adjacent second label 174B on display 120. Although only two labels are shown in FIG. 11B, graphical user interface (GUI) 150C may be configured to include any number of labels 174.

[0145] 11C , a perspective view of the vertebrae is displayed in a graphical user interface (GUI) 150C, including the locations of various virtual boundaries (Boundaries 1, 2, 8, 9) and / or alert zones (Zone 1). Although not shown in FIG. 11C , it is also contemplated that the graphical user interface (GUI) 150 of FIG. 11C may further include a planning interface 166 having one or more buttons 168 configured to enable the surgeon to manipulate various alerts and / or the locations of various virtual boundaries (Boundaries 1, 2, 8, 9) and / or the location of an alert zone (Zone 1) that can be defined to trigger various alerts. Furthermore, the graphical user interface (GUI) 150C may also include alert indicators 172, 166 (not shown) positioned within the display of the anatomical shape for the various virtual boundaries (Boundaries 1, 2, 8, 9) and / or alert zones (Zone 1). As noted above, the graphical user interface (GUI) 150C may be configured to include any number of labels 174. 11C illustrates an example configuration of a graphical user interface (GUI) 150C that includes multiple labels 174A, 174B, 174C. The graphical user interface (GUI) 150C may be configured to allow a surgeon to navigate among the various anatomical structures associated with each of the various labels 174A, 174B, 174C by selecting the label 174A, 174B, 174C of the anatomical structure they choose to display.

[0146] 12A-12C, an alternative exemplary graphical user interface (GUI) 150D shown on the display 120 of the navigation system 100 is illustrated. The graphical user interface (GUI) 150D may include any and / or all of the features, buttons, and / or elements of the graphical user interface (GUI) 150C of FIGS. 11A-11C described above. Furthermore, the graphical user interface (GUI) 150D may function and / or operate in the same or similar manner as the graphical user interface (GUI) 150C of FIGS. 11A-11C described above. The graphical user interface (GUI) 150D shown in FIGS. 12A-12C may further include a view button 176 that the surgeon can operate to switch and / or toggle between views of the anatomical features, including various virtual boundaries (Boundaries 1, 2, 8, 9) and / or alert zones (Zone 1). For example, in FIG. 12A , the view button 176 indicates that the graphical user interface (GUI) 150D is displaying an axial view of the anatomical feature. Alternatively, the surgeon can use the view button 176 to cause the graphical user interface (GUI) 150D to display various views of the anatomical features and associated virtual boundaries (boundaries 1, 2, 8, 9) and / or alert zones (zone 1). For example, with reference to FIG. 12B , the view button 176 indicates that the graphical user interface (GUI) 150D is displaying a sagittal view of the anatomical feature. With reference to FIG. 12C , the view button 176 indicates that the graphical user interface (GUI) 150D is displaying a planar map view of the anatomical feature.

[0147] It is also contemplated that the graphical user interface (GUI) 150D may also include zoom buttons 178 configured to allow the operator to manipulate the image on the display 120 of the navigation system 100 by zooming in and / or out. An exemplary configuration of the zoom buttons 178 of the graphical user interface (GUI) 150D is shown in Figures 12A and 12B. The zoom buttons 178 may be included in any of the graphical user interfaces (GUIs) described herein.

[0148] 13A and 13B, an exemplary graphical user interface (GUI) 150E is shown on the display 120 of the navigation system 100 during navigation of the surgical instruments 220, 320, 420 during placement of an implant 275. Similar to the graphical user interface (GUI) 150 described above, the graphical user interface (GUI) 150E includes labels 174 that identify the anatomical structures displayed in the graphical user interface (GUI) 150E. Additionally, the graphical user interface (GUI) 150E also includes view buttons 176 configured to allow the surgeon to toggle between views. For example, the surgeon can use the view button 176 to cause the graphical user interface (GUI) 150E to display a sagittal view of the anatomical structures shown in FIG. 13A. Alternatively, the surgeon can use the view button 176 to cause the graphical user interface (GUI) 150E to display an axial view of the anatomical structures shown in FIG. 13B. Although not shown, it is contemplated that view button 176 may be used to cause graphical user interface (GUI) 150E to display additional views of the anatomy.

[0149] Additionally, the graphical user interface (GUI) 150E can be configured to display the virtual boundaries (boundaries 5, 6, 7, and 8) and / or alert zones defined using the navigation system 100. As described above, the navigation system 100 can be configured to send a signal or command to the instrument processor 215, 315, 415 to trigger one of the various alerts described above based on the position of the end effector 240, 340, 440 relative to one of the virtual boundaries (boundaries 5, 6, 7, and 8) and / or alert zones during navigation of the surgical instrument 220, 320, 420. As shown in FIGS. 13A and 13B, multiple virtual boundaries (boundaries 5, 6, 7, and 8) and / or alert zones (zone 4) are illustrated in a known coordinate system based on information selected and / or input by the surgeon in the alert interface 151 described in FIG. 8. The virtual boundaries (boundaries 5, 6, 7, and 8) and / or alert zone (zone 4) are configured to trigger an alert. 13A and 13B, the virtual boundaries (Boundaries 5, 6, 7) may correspond to a desired depth for inserting the end effector corresponding to each virtual boundary (Boundary 5, 6, 7). The navigation system 100 can be configured to send a signal or command to the instrument processor 215, 315, 415 to trigger an alert based on the position of the end effector 240, 340, 440 relative to the corresponding virtual boundary (Boundary 5, 6, 7) as part of assisting the surgeon in navigating the surgical instrument 220, 320, 420 to place the implant 275 or device.

[0150] Additionally, the graphical user interface (GUI) 150E can be configured to display a planned pose 280 of the implant 275 or device on the display. For example, as shown in Figures 13A and 13B, the graphical user interface (GUI) 150E can display an outline showing the planned pose 280 of the implant within a known coordinate system to assist the surgeon in navigating the surgical instruments 220, 320, 420 to place the implant 275 or device. As seen in Figures 13A and 13B, the graphical user interface (GUI) 150E can display the end effector 240C pushing the implant 275 into position relative to the planned pose 280 and virtual boundaries (boundaries 5, 6, and 7).

[0151] Additionally, the graphical user interface (GUI) 150E may also include additional user interface buttons 180, 182. The user interface button 180 may be configured to lock or unlock the screen. For example, the surgeon may operate the user interface button 180 to lock the screen to prevent additional and / or inadvertent changes to the graphical user interface (GUI) 150E. Alternatively, the user interface button 182 may be configured to take a screenshot and / or capture an image currently displayed in the graphical user interface (GUI) 150E. For example, the surgeon may operate the user interface button 182 to capture an image displayed in the graphical user interface (GUI) 150E during navigation of the surgical instruments 220, 320, 420 during surgery. The user interface button 182 may also be configured to activate and / or deactivate video recording of images displayed in the graphical user interface (GUI) 150E. For example, the surgeon can operate user interface button 182 to start and stop video recording of images displayed in graphical user interface (GUI) 150E during navigation of surgical instruments 220, 320, 420 during surgery.

[0152] Although not shown, during navigation of the surgical instrument 220, 320, 420, if one of various alerts is triggered based on the position of the end effector 240, 340, 440 relative to one or more of the virtual boundaries and / or alert zones, the graphical user interface (GUI) 150 may be configured to provide or display a snooze button that allows the user to snooze and / or temporarily deactivate the triggered alert. The graphical user interface (GUI) 150 may be configured to temporarily disable one or more of such alerts upon activation of the snooze button. For example, activation of the snooze button may temporarily suspend the triggered alert for a predetermined period of time, such as two seconds. After the predetermined period of time has elapsed, the alert can be reactivated and triggered if warranted based on the position of the end effector 240, 340, 440 relative to one or more of the virtual boundaries and / or alert zones. As noted above, it is contemplated that a snooze button may be operated to temporarily deactivate a triggered alert until the end effector 240, 340, 440 has moved a predetermined distance further relative to one or more of the virtual boundaries and / or alert zones. Once the end effector 240, 340, 440 has moved a predetermined distance relative to one or more of the virtual boundaries and / or alert zones, the alert may be reactivated. Alerts may be triggered by the direction of movement of the handpiece 225, 325, 425 as determined by the navigation system 140 and the position of the end effector 240, 340, 440 relative to one or more of the virtual boundaries and / or alert zones. Various scenarios for triggering, snoozing, and / or reactivating various alerts are described in more detail above.

[0153] An example of the operation of the snooze function is as follows. [Table 1]

[0154] <Surgical instrument navigation method> A method for navigating a surgical instrument using a navigation system can include defining virtual boundaries (boundaries 5, 6, 7) and / or alert zones (e.g., zones 1, 2, 3, and 4) within pre-operative and / or intra-operative data of the patient 20 provided by the imaging system 500 described above or other similar means of imaging the surgical site 30 of the patient 20. The method can further include identifying and / or aligning the virtual boundaries (boundaries 5, 6, 7) and / or alert zones (zones 1, 2, 3, 4) with the patient. For example, this can be accomplished by using the user input 130 of the surgical navigation system 100 to identify and / or mark the virtual boundaries (boundaries 5, 6, 7) and / or alert zones (zones 1, 2, 3, 4) within the pre-operative and / or intra-operative data. Defining virtual boundaries (Boundaries 5, 6, 7) and / or alert zones (Zones 1, 2, 3, 4) can include marking boundaries surrounding critical anatomical structures, such as nerves, that the surgeon wants to avoid during the medical procedure. It is also contemplated that various virtual boundaries (Boundaries 5, 6, 7) can be identified by the surgical navigation system using a segmentation algorithm and / or boundary generator. The virtual boundaries (Boundaries 5, 6, 7) can be user-selectable and / or modifiable. Multiple zones, such as a first alert zone, Zone 1, can be established to notify the surgeon that a critical anatomical structure is being approached. The first alert zone, Zone 1, can be defined at least in part by a first virtual boundary, Boundary 1, and a second virtual boundary, Boundary 2, the first and second boundaries being separated by a user-selectable distance and / or depth, and the volume defined between the first and second boundaries represents the alert zone, Zone 1. A second alert zone, Zone 2, can be defined within the first alert zone, Zone 1, and is intended to notify the surgeon that they are getting closer to critical anatomical structures.A third alert zone, Zone 3, can be defined within both the first alert zone, Zone 1, and the second alert zone, Zone 2, and is intended to notify the surgeon that the third alert zone, Zone 3, is a critical anatomical structure, is at its periphery, and is about to penetrate the critical anatomical structure. A fourth alert zone, Zone 4, can be defined on the periphery of the vertebra opposite the vertebral surface where the end effector 240, 340, 440 first enters the vertebra. Each of the various alert zones can be defined, at least in part, as an area or volume defined between two or more virtual boundaries. If the end effector 240, 340, 440 is approaching the periphery of the vertebra and is in danger of penetrating the periphery, the fourth alert zone, Zone 4, can notify the surgeon. This step can further include defining a planned surgical path, such as defining a target trajectory, axis T, and / or target position T. The target trajectory axis T may include a preferred trajectory and / or orientation for positioning the surgical instrument 220, 320, 420 to reach the target position T. The target trajectory axis T may be established based on a combination of factors, which may include, but are not limited to, avoiding critical anatomical structures, the type of medical procedure being performed, the type of implant being inserted, and the desired position and / or orientation of the implant. For example, the target axis axis T may be established based on a preferred angle and / or location for inserting a pedicle screw to attach a support member to the spine.

[0155] The method can further include tracking the surgical instrument 220, 320, 420 using the position and orientation of the instrument tracking device 230, 330, 430 relative to the patient 20 and / or surgical site 30. This can be accomplished using the surgical navigation system 100. The instrument tracking device 230, 330, 430 of the surgical instrument 220, 320, 420 can be aligned with the surgical navigation system 100. The surgical navigation system 100 can then use the tracking unit 110 to track the position, orientation, and / or posture of the surgical instrument 220, 320, 420 during the medical procedure.

[0156] The method may further include manipulating the speed of the variable speed motor 245, 345, 445 of the surgical instrument 220, 320, 420 between a maximum cutting speed and a minimum cutting speed based on the position of the surgical instrument 220, 320, 420 relative to the defined virtual boundaries (boundaries 4, 5, 6, 7) and / or alert zones, zones 1, 2, 3. For example, the surgical navigation system 100 can be configured to communicate to the instrument processor 215, 315, 415 of the surgical instrument 220, 320, 420 that the surgical instrument 220, 320, 420 is adjacent to and / or distal to a virtual boundary (boundaries 1, 2, 3, 4, 5, 6, 7) and / or has entered the first alert zone, Zone 1, and further to cause the instrument processor 215, 315, 415 to reduce the speed of the motor 245, 345, 445 from a maximum cutting speed to a minimum cutting speed to notify the surgeon that the surgical instrument 220, 320, 420 has entered the first alert zone, Zone 1. The surgical navigation system 100 can further be configured to communicate to the instrument processor 215, 315, 415 of the surgical instrument 220, 320, 420 that the end effector 240, 340, 440 of the surgical instrument 220, 320, 420 is about to breach the third alert zone, Zone 3, and to instruct the instrument processor 215, 315, 415 to reduce the speed of the motor 245, 345, 445 and / or disable the motor to notify the surgeon that the surgical instrument 220, 320, 420 is about to breach the third alert zone, Zone 3, and to prevent the surgical instrument 220, 320, 420 from contacting and / or damaging critical anatomical structures.When the surgical instrument 220, 320, 420 enters one of the surgeon-defined alert zones (Zones 1, 2, 3), slowing the variable speed motor 245, 345, 445 from a maximum cutting speed to a minimum cutting speed can produce an audibly perceptible change in the pitch generated by the variable speed motor 245, 345, 445 to notify the surgeon that the surgical instrument 220, 320, 420 is adjacent to and / or distal to a virtual boundary (Boundaries 1, 2, 3, 4, 5, 6, 7) and / or is entering one of the alert zones (Zones 1, 2, 3) without impairing the ability of the surgical instrument 220, 320, 420 to continue cutting biological tissue. Maintaining a minimum cutting speed prevents the end effectors 240, 340, 440 of the surgical instruments 220, 320, 420 from grabbing or entangling and moving in an undesired direction, potentially damaging critical anatomical structures within the patient 20.

[0157] Further, the step of manipulating the speed of the variable speed motor 245, 345, 445 of the surgical instrument 220, 320, 420 between a maximum cutting speed and a minimum cutting speed based on the position of the surgical instrument 220, 320, 420 may also include manipulating the speed of the variable speed motor 245, 345, 445 of the surgical instrument 220, 320, 420 between a maximum cutting speed and a minimum cutting speed based on the position of the surgical instrument 220, 320, 420 relative to the defined target trajectory, axis T, and / or target position T. For example, the surgical navigation system 100 can be configured to communicate to the instrument processor 215, 315, 415 of the surgical instrument 220, 320, 420 that the surgical instrument 220, 320, 420 is deviating from the target trajectory, axis T, and further to cause the instrument processor 215, 315, 415 to reduce the speed of the motor 245, 345, 445 from a maximum cutting speed to a minimum cutting speed to notify the surgeon that the surgical instrument 220, 320, 420 is deviating. Furthermore, the surgical navigation system 100 can be configured to communicate to the instrument processor 215, 315, 415 of the surgical instrument 220, 320, 420 that the end effector 240, 340, 440 of the surgical instrument 220, 320, 420 has reached the target position T, and further to instruct the instrument processor 215, 315, 415 to reduce the speed of the motor 245, 345, 445 and / or disable the motor to notify the surgeon that the surgical instrument 220, 320, 420 has reached the target position T.

[0158] The method may further include activating an alert device 255, 355, 455 to generate at least one audible, tactile, or visual notification based on the position of the surgical instrument 220, 320, 420 relative to the defined virtual boundaries (Boundaries 1, 2, 3, 4, 5, 6, 7) and / or alert zones (Zones 1, 2, 3). For example, the surgical navigation system 100 can be configured to communicate to the instrument processor 215, 315, 415 of the surgical instrument 220, 320, 420 that the surgical instrument 220, 320, 420 is adjacent and / or distal to a first virtual boundary (Boundary 1) and / or has entered a first alert zone, Zone 1, and further instruct the instrument processor 215, 315, 415 to activate the alert device 255, 355, 455 to generate at least one audible, tactile, or visual notification notifying the surgeon that the surgical instrument 220, 320, 420 is adjacent and / or distal to the first virtual boundary (Boundary 1) and / or has entered the first alert zone, Zone 1. It is also contemplated that combinations of alert devices 255, 355, 455 and notification types may be used. For example, the surgical navigation system 100 can be configured to communicate to the instrument processor 215, 315, 415 of the surgical instrument 220, 320, 420 that the surgical instrument 220, 320, 420 is adjacent to and / or distal to a first virtual boundary (Boundary 1) and / or has entered Zone 1, the first alert zone, and further instruct the instrument processor 215, 315, 415 to activate the alert device 255, 355, 455 to generate an audible notification notifying the surgeon that the surgical instrument 220, 320, 420 is adjacent to and / or distal to the first virtual boundary (Boundary 1) and / or has entered Zone 1, the first alert zone.The surgical navigation system 100 can then be configured to communicate to the instrument processor 215, 315, 415 of the surgical instrument 220, 320, 420 that the surgical instrument 220, 320, 420 is adjacent to and / or distal to a second virtual boundary (Boundary 2) and / or has entered Zone 2, a second alert zone, and further instruct the instrument processor 215, 315, 415 to activate the alert device 255, 355, 455 to generate a tactile notification notifying the surgeon that the surgical instrument 220, 320, 420 is adjacent to and / or distal to the second virtual boundary (Boundary 2) and / or has entered Zone 2, a second alert zone. The surgical navigation system 100 can further be configured to communicate to the instrument processor 215, 315, 415 of the surgical instrument 220, 320, 420 that the end effector 240, 340, 440 of the surgical instrument 220, 320, 420 is adjacent to and / or distal to a third virtual boundary (Boundary 3) and / or is about to breach Zone 3, the third alert zone, and to instruct the instrument processor 215, 315, 415 to reduce the speed of the motor 245, 345, 445 and / or disable the motor to notify the surgeon that the surgical instrument 220, 320, 420 is adjacent to and / or distal to the third virtual boundary (Boundary 3) and / or is about to breach Zone 3, the third alert zone, and to prevent the surgical instrument 220, 320, 420 from contacting and / or damaging critical anatomical structures. This is merely an exemplary configuration of various combinations of alerts that may be generated from the surgical system 10 during a medical procedure. It is contemplated that any type and / or combination of alert(s) may be assigned to the various virtual boundaries (Boundaries 1, 2, 3, 4, 5, 6, 7, 8, 9) and / or alert zones, target trajectories, and / or target location(s). Alerts may be assigned by the surgeon at the time the surgical navigation system 100 is used to define the various alert zones, target trajectories, and / or target location(s) within the pre-operative and / or intra-operative data.

[0159] An alternative method for navigating a surgical instrument 220, 320, 420 using the surgical navigation system 100 during a medical procedure on a patient can include a surgical instrument 220, 320, 420 having a handpiece 225, 325, 425 and an end effector 240, 340, 440 coupled to the handpiece 225, 325, 425. The surgical instrument 220, 320, 420 can include a variable speed motor 245, 345, 445 for selectively driving the end effector 240, 340, 440 and a processor 215, 315, 415 for controlling energization of the variable speed motor 245, 345, 445. The method can include selecting a medical implant 275, such as a pedicle screw. The method can also include identifying a location within patient data stored in the surgical navigation system 100 to place the medical implant 275 on the patient 20. For example, a medical professional can use a user input device 130, such as a keyboard, touch screen, or similar device, to select a location or portion of the patient 20, such as a vertebra, where an implant 275 will be placed. The surgical navigation system 100 can then be configured to define various virtual boundaries (boundaries 1, 2, 3, 4, 5, 6, 7, 8, 9) based on the selected medical implant 275 and the identified location where the medical implant 275 will be placed. Alternatively, it is contemplated that the surgical navigation system 100 can be configured to identify the type of end effector 240, 240, 440 coupled to the handpiece 225, 325, 425 of the surgical instrument 220, 320, 420 and define one or more virtual boundaries (boundaries 1, 2, 3, 4, 5, 6, 7, 8, 9) based on the type of end effector 240, 340, 440 and / or the location of the surgery. For example, during a drilling procedure, the surgical navigation system can be configured to define a first boundary corresponding to a drill, a second boundary corresponding to a tap, and a third boundary corresponding to a driver for placing the implant 275, each of the virtual boundaries being defined along axis T, which is a target trajectory, based on the planned pose of the implant 275.

[0160] The method can also include tracking the position of the surgical instrument 220, 320, 420 using the surgical navigation system 100. This can include using machine vision and / or an instrument tracker 230, 330, 430 coupled to the surgical instrument 220, 320, 420. When the surgical navigation system 100 determines that the surgical instrument 220, 320, 420 has entered one of the defined virtual boundaries (Boundaries 1, 2, 3, 4, 5, 6, 7, 8, 9) and / or alert zones Zones 1-8B, the surgical navigation system 100 can be configured to send a signal to the processor 215, 265, 315, 415 to stop the variable speed motor 245, 345, 445. For example, the surgical navigation system 100 can be configured to send a signal to the battery processor 265 of the first surgical instrument 220, which is in communication with the first instrument processor 215. The battery processor 265 and / or the instrument processor 215 may be configured to prevent current from flowing from a power source, such as the battery 260, to the variable speed motor 245. This can be accomplished using wired or wireless communication between the surgical navigation system 100 and the surgical instrument 220, 320, 420.

[0161] The method may further include manipulating the virtual boundaries (Boundaries 1, 2, 3, 4, 5, 6, 7, 8, and 9) defined by the surgical navigation system and / or the alert zones, Zones 1-8B, based on the preferences of the medical professional. For example, the medical professional may increase the size and / or thickness of the alert zones to provide early warning that the surgical instrument 220, 320, or 420 is approaching a boundary or critical anatomical structure. Additionally, the medical professional may reposition the alert zones within the patient data. This may include changing the size, shape, and / or number of alert zones defined within the patient data. The medical professional may similarly manipulate the axial position and / or depth of the virtual boundaries (Boundaries 1, 2, 3, 4, 5, 6, 7, 8, and 9) along the target trajectory axis T to provide specific alerts to the end effector. The axial position and / or depth of the virtual boundaries (Boundaries 1, 2, 3, 4, 5, 6, 7, 8, 9) along the target trajectory axis T can also be manipulated to provide early warning that the surgical instrument 220, 320, 420 is approaching a boundary or target depth based on the planned pose of the implant 275. Additionally, the medical professional can also reposition the virtual boundaries (Boundaries 1, 2, 3, 4, 5, 6, 7, 8, 9) within the patient data. This can include changing the position, depth, shape, and / or number of the virtual boundaries (Boundaries 1, 2, 3, 4, 5, 6, 7, 8, 9) defined within the patient data.

[0162] If the surgical tool assembly 200, 300, 400 includes multiple end effectors 240, 340, 440 removably coupleable to the handpiece 225, 325, 425, the method may further include coupling a first end effector 240A, 340A to the handpiece 225, 325. The surgical navigation system 100 may be configured to identify the first end effector 240A, 340A and define a first boundary and / or a first alert zone based at least in part on the first end effector. The first boundary may include a target depth for the first end effector 240A, 340A. The method may also include coupling a second end effector 240B, 340B to the handpiece 225, 325. The surgical navigation system 100 can be configured to identify a second end effector 240B, 340B and define a second boundary and / or a second alert zone based at least in part on the second end effector 240B, 340B. The second boundary can include a target depth for the second end effector 240B, 340B, which can be different from the first boundary defined based on the first end effector 240A, 340A.

[0163] The method may further include activating an alert device 255, 355, 455 when the surgical navigation system 100 determines that the surgical instrument 220, 320, 420 has entered one of the defined alert zones. This may include activating an audible or tactile alert device. Additionally, this may include stopping the variable speed motor 245, 345, 445 of the surgical instrument 220, 320, 420. The method may also include reducing the speed of the variable speed motor 245, 345, 445 from a maximum cutting speed to a minimum cutting speed. The change in speed may create a tactile and / or audible alert that can be perceived by the medical professional.

[0164] The method can further include assigning an alert type to each of the defined virtual boundaries and / or alert zones. The surgical navigation system 100 can be configured to automatically assign one or more of various types of alerts to each of the defined virtual boundaries and / or alert zones based on a previously stored profile or system configuration for the medical professional. Alternatively, the medical professional can use the user input device 130 to assign one or more of various alert types to each of the defined virtual boundaries and / or alert zones.

[0165] The method may further include identifying a first end effector 240A, 340A coupled to the handpiece 225, 325, wherein the surgical navigation system 100 may be configured to define a first boundary and / or a first alert zone based at least in part on the first end effector 240A, 340A. The method may then include disconnecting the first end effector 240A, 340A from the handpiece 225, 325 and coupling a second end effector 240B, 340B to the handpiece 225, 325, wherein the surgical navigation system 100 may be configured to identify the second end effector 240B, 340B and define a second boundary and / or a second alert zone based at least in part on the second end effector 240B, 340B.

[0166] The method may further include identifying a first end effector 240A, 340A coupled to the handpiece 225, 325, and the surgical navigation system 100 may be configured to define a first boundary and / or a first alert zone based at least in part on the first end effector 240A, 340A. The method may then include applying the first end effector 240A, 340A to the biological tissue at the location where the medical implant is to be placed. When the surgical navigation system 100 determines that the surgical instrument 220, 320, 420 is adjacent and / or distal to the first virtual boundary and / or has entered the first alert zone, the surgical navigation system 100 may be configured to send a signal to the processor 215, 265, 315, 415 to stop the variable speed motor 245, 345, 445. It is also contemplated that the surgical navigation system 100 can be configured to send a signal that activates one of the above-described alert devices to generate one of the various types of alerts described above. Next, the method may include disconnecting the first end effector 240A, 340A from the handpiece 225, 325 and coupling the second end effector 240B, 340B to the handpiece 225, 325, 425. The surgical navigation system 100 can be configured to identify the second end effector 240B, 340B and define a second boundary and / or a second alert zone based at least in part on the second end effector 240B, 340B. The method may also include applying the second end effector 240B, 340B to the biological tissue at the location where the medical implant is to be placed. When the surgical navigation system 100 determines that the surgical instrument 220, 320, 420 is adjacent and / or distal to the second virtual boundary and / or has entered a second alert zone, the surgical navigation system 100 can be configured to send a signal to the processor to stop the variable speed motor. It is also contemplated that the surgical navigation system 100 can be configured to send a signal to activate one of the alert devices described above to generate one of the various types of alerts described above.

[0167] In another configuration, the navigation system is configured to communicate a first signal to a processor of the control console based on the position of the end effector relative to the alert zone. This signal can cause the control console to compare the sensed speed and desired speed of the handpiece based on a torque map. Using the torque map, the console can determine a calculated torque for the cutting accessory based on the sensed speed of the cutting accessory. Then, based on the calculated torque of the cutting accessory and the sensed speed of the cutting accessory, the console can determine a calculated power to be consumed by the cutting accessory. The torque map can then provide a desired power to be consumed by the cutting accessory, as well as a desired torque and desired speed of the cutting accessory at the desired power consumed. The navigation system may also be configured to cause the console to adjust the torque map based on the end effector entering the alert zone. Specifically, when the end effector is adjacent and / or distal to the virtual boundary and / or enters the alert zone, the control console can apply reduced torque and power to the bar so that the end effector cuts less effectively and / or aggressively when the end effector is adjacent and / or distal to the virtual boundary and / or within the alert zone.

[0168] Items covering additional configurations of the above system(s): Item I 1. A surgical instrument assembly for use in conjunction with a navigation system configured to enable a medical professional to define an alert zone on a patient to assist the medical professional in performing spinal or cranial surgery on the patient, the surgical instrument assembly comprising: a control console including a control processor in communication with the navigation system; a high-speed surgical burr including a variable speed motor in communication with the control processor, the variable speed motor configured to rotate the burr at a first cutting speed greater than 70,000 revolutions per minute and a second cutting speed less than 70,000 revolutions per minute and greater than 60,000 revolutions per minute; a foot switch in communication with the control processor for controlling operation of the variable speed motor of the high speed surgical burr; Including, the navigation system is configured to actively determine a position of the high-speed surgical burr relative to the patient; the navigation system is configured to, when the navigation system determines that the high-speed surgical burr has entered the alert zone, send a signal to the control processor to operate the variable speed motor of the high-speed surgical burr to transition the rotation of the burr from the first cutting speed to the second cutting speed; the transition of the burr from the first cutting speed to the second cutting speed produces an audible perceptible change in pitch produced by the high-speed surgical burr as the burr transitions from the first cutting speed to the second cutting speed, notifying the medical professional that the high-speed surgical burr has entered the alert zone without compromising the ability of the burr to continue cutting living tissue. Item II 2. The surgical instrument assembly of claim 1, wherein the transition of the burr from the first cutting speed to the second cutting speed creates a tactile perceptual change in the high speed surgical burr as the burr transitions from the first cutting speed to the second cutting speed, notifying the medical professional that the high speed surgical burr has entered the alert zone without compromising the ability of the burr to continue cutting living tissue. Item III the foot switch is movable between a first position and a second position; Item 1. The surgical instrument assembly of item 1, wherein the variable speed motor is configured to stop when the foot switch is in the first position, and the variable speed motor is configured to rotate the burr at at least 60,000 revolutions per minute when the foot switch is in the second position. Item IV Item 10. The surgical instrument assembly of item I, further comprising an audible alert device configured to emit an alert sound when the high-speed surgical burr enters the alert zone. Item V 8. The surgical instrument assembly of claim 1, further comprising a tactile alert device in contact with the medical professional, the tactile alert device configured to emit a physical alert perceptible to the medical professional when the high-speed surgical burr enters the alert zone. Item VI 9. The surgical instrument assembly of claim V, wherein the tactile alert device is coupled to the foot switch such that the physical alert is felt within an appendage of the medical professional contacting the foot switch that controls operation of the variable speed motor of the high-speed surgical burr. Item VII the alert zone includes a first zone and a second zone; Item V. The surgical tool assembly of item V, wherein the tactile device is configured to generate a first notification when the high-speed surgical burr enters the first zone and to generate a second notification when the high-speed surgical burr enters the second zone. Item VIII 8. The surgical instrument assembly of claim 1, further comprising an audible alert device and a tactile alert device in contact with the medical professional, the audible alert device and the tactile alert device each capable of generating an alert perceptible by the medical professional when the high-speed surgical burr enters the alert zone. Item IX and further including at least one of an audible alert device capable of generating the first notification and a tactile alert device capable of generating the second notification; the alert zones include a user-definable first zone and a user-definable second zone; the navigation system is configurable to allow the user to assign one of the first notification or the second notification to either the first zone or the second zone; Item 10. The surgical instrument assembly of claim 1, wherein the navigation system is configurable to operate one of the audible alert device and the tactile alert device based on the position of the high-speed surgical burr and the first notification or the second notification assigned to either the first zone or the second zone. Item X 1. A surgical system for use by a medical professional in spinal or cranial surgery on a patient, the surgical system comprising: a control console including a control processor; a high-speed surgical burr including a variable speed motor in communication with the control processor, the variable speed motor configured to rotate the burr at a first cutting speed greater than 70,000 revolutions per minute and a second cutting speed between 60,000 revolutions per minute and 65,000 revolutions per minute; a foot switch in communication with the control processor for controlling operation of the variable speed motor of the high speed surgical burr; a navigation system in communication with the control console, the navigation system configured to enable the medical professional to define an alert zone on the patient, actively determine a position of the high-speed surgical burr relative to the patient, and communicate the position to the control processor; Including, the navigation system is configured to, when the navigation system determines that the burr of the high-speed surgical burr has entered the alert zone, communicate a signal to the control processor to operate the variable speed motor of the high-speed surgical burr to transition the rotation of the burr from the first cutting speed to the second cutting speed; the transition of the burr from the first cutting speed to the second cutting speed produces an audible perceptible change in pitch of the variable speed motor of the high-speed surgical burr to notify the medical professional that the high-speed surgical burr has entered the alert zone without compromising the ability of the burr to continue cutting living tissue. Item XI Item X. The surgical system of claim X, wherein the transition of the burr from the first cutting speed to the second cutting speed generates a tactile perceptual change in the high-speed surgical burr as the burr transitions from the first cutting speed to the second cutting speed to notify the medical professional that the high-speed surgical burr has entered the alert zone without compromising the burr's ability to continue cutting living tissue. Item XII the foot switch is movable between a first position and a second position; Item XI. The surgical system of claim XI, wherein the variable speed motor is configured to stop when the foot switch is in the first position, and the variable speed motor is configured to rotate the burr at at least 60,000 revolutions per minute when the foot switch is in the second position. Item XIII Item X. The surgical system of claim X, further comprising an audible alert device configured to emit an alert sound when the high-speed surgical burr enters the alert zone. Item XIV Item X. The surgical system of claim X, further including a tactile alert device in contact with the medical professional, the tactile alert device configured to emit a physical alert perceptible to the medical professional when the high-speed surgical burr enters the alert zone. Item XV 16. The surgical system of claim 14, wherein the tactile alert device is coupled to the foot switch such that the physical alert is felt within an appendage of the medical professional contacting the foot switch that controls operation of the variable speed motor of the high-speed surgical burr. Item XVI the alert zone includes a first zone and a second zone; Item XIV. The surgical system of claim XIV, wherein the tactile alert device is configured to generate a first notification when the high-speed surgical burr enters the first zone and to generate a second notification when the high-speed surgical burr enters the second zone. Item XVII Item X. The surgical system of claim X, further comprising an audible alert device and a tactile alert device in contact with the medical professional, the audible alert device and the tactile alert device each capable of generating an alert perceptible by the medical professional when the high-speed surgical burr enters the alert zone. Item XVIII 1. A surgical system for use in conjunction with a surgical navigation system that allows definition of alert zones on a patient to assist a medical professional in performing spinal or cranial surgery on the patient, the surgical system comprising: a high-speed surgical burr having a variable speed motor configured to rotate the burr; a control console including a control processor in communication with the variable speed motor of the high-speed surgical burr, the control processor configured to receive data from the surgical navigation system regarding the defined alert zone and a position of the high-speed surgical burr relative to the defined alert zone; a foot switch in communication with the control processor, the foot switch movable between a first position and a second position to control operation of the variable speed motor of the high speed surgical burr; Including, When the foot switch is in the first position, the variable speed motor is stopped and the bar rotates at 0 revolutions per minute; When the foot switch is in the second position, the variable speed motor is configured to rotate the bur at a maximum cutting speed; when the foot switch is in an intermediate position between the first position and the second position, the variable speed motor is configured to rotate the burr at an intermediate speed between a minimum cutting speed and the maximum cutting speed; the navigation system is configured to transmit data to the control processor that the burr has entered the alert zone, and further to operate the variable speed motor of the high-speed surgical burr to reduce rotation of the burr to the minimum cutting speed when the foot switch is disposed in the intermediate position or the second position. Item XIX a tactile alert device coupled to the foot switch and in communication with the control console; Item XVIII. The surgical system of claim XVIII, wherein the control console is configured to operate the tactile alert device to generate a physical notification perceptible to the medical professional when the bar enters the alert zone. Item XX 1. A surgical instrument assembly for use in conjunction with a navigation system that allows definition of alert zones on a patient to assist a medical professional in performing spinal or cranial surgery on the patient, the surgical instrument assembly comprising: a high-speed surgical burr having a variable speed motor configured to rotate the burr; a control console including a control processor configured to communicate with the variable speed motor of the high-speed surgical burr and to receive data from the surgical navigation system; a foot switch in communication with the control processor to control operation of the variable speed motor of the high-speed surgical burr, the foot switch having a tactile alert device; Including, the navigation system is configured to send data to the control processor that the bur has entered the defined alert zone, and is further configured to operate the tactile alert device of the foot switch to notify the medical professional when the bur has entered the alert zone. Item XXI 1. A method of navigating a medical instrument having a variable speed motor using a navigation system including an instrument tracking device coupled to the medical instrument and a patient tracking device coupled to a patient, the method comprising: defining an alert zone within the patient's preoperative data; aligning the alert zone with the patient tracking device; tracking the position of the medical instrument using the position and orientation of the instrument tracking device relative to the patient tracking device; manipulating the speed of the variable speed motor of the medical instrument between a maximum cutting speed and a minimum cutting speed based on the position of the medical instrument relative to the defined alert zone; A method comprising: Item XXII Item XXI. The method of item XXI, wherein manipulating the speed of the variable speed motor also includes decelerating the variable speed motor from the maximum cutting speed to the minimum cutting speed when the medical instrument enters the defined alert zone. Item XIII Item XXII. The method of claim XXII, wherein slowing the variable speed motor from the maximum cutting speed to the minimum cutting speed as the medical instrument enters the defined alert zone produces an audible perceptible change in pitch generated by the variable speed motor to notify a medical professional that the medical instrument has entered the defined alert zone without compromising the ability of the medical instrument to continue cutting biological tissue. Item XXIV Item XXI. The method of item XXI, further comprising activating an alert device to generate at least one of an audible notification, a tactile notification, or a visual notification based on the position of the medical instrument relative to the defined alert zone. Item XXV the defined alert zones include a first zone and a second zone; 20. The method of claim XXIV, wherein the step of activating the alert device includes generating the tactile notification when the medical instrument enters the first zone and generating the audible notification when the medical instrument enters the second zone. Item XXVI 1. A surgical system for use by a medical professional in spinal or cranial surgery on a patient, the surgical system comprising: 1. A handheld surgical instrument configured to actuate an end effector, comprising: A variable speed motor; a trigger operable by the medical professional between a first position and a second position; a trigger sensor configured to detect the position of the trigger and output a first signal indicative of the position of the trigger; a handpiece processor in communication with the trigger sensor, the handpiece processor configured to control energization of the variable speed motor based at least in part on the first signal indicative of the position of the trigger; a handheld surgical instrument, a rechargeable battery module detachably coupled to the handheld surgical instrument, a transceiver configured to transmit and receive signals; a battery processor in communication with the transceiver, the battery processor configured to power the handheld surgical instrument; a rechargeable battery module including: a navigation system in communication with the battery processor via the transceiver, the navigation system configured to actively determine a position of the surgical instrument relative to an alert zone defined on the patient; and Including, the navigation system is configured to communicate a second signal to the battery processor to cut power to the handheld surgical instrument when the navigation system determines that the position of the surgical instrument has entered the alert zone; A surgical system, wherein if the battery processor cuts off power to the handheld surgical instrument and the surgical instrument remains in the alert zone, the handpiece processor is configured to prevent energization of the variable speed motor until a subsequent first signal is received from the trigger sensor indicating that the medical professional has manipulated the position of the trigger. Item XXVII The rechargeable battery module further comprises: a cell for storing electrical energy to power the variable speed motor of the handheld surgical instrument; a switch in communication with the battery processor and configured to control the flow of electrical energy from the cell, the switch having a conducting state configured to allow the flow of electrical energy from the cell and a non-conducting state configured to prevent the flow of electrical energy from the cell; Item XXVI. The surgical system according to item XXVI, comprising: Item XXVIII 1. A surgical system for use by a medical professional in performing surgery on a patient, the surgical system comprising: 1. A handheld surgical instrument configured to actuate an end effector, comprising: A variable speed motor; a switch operable by the medical professional between a first position and a second position; a switch sensor configured to detect the position of the switch and output a first signal indicative of the position of the switch; a handpiece processor in communication with the switch sensor, the handpiece processor configured to control energization of the variable speed motor based at least in part on the first signal indicative of the position of the switch; a handheld surgical instrument, a power source removably coupled to the handheld surgical instrument and configured to provide power to the handheld surgical instrument; a navigation system in communication with the handpiece processor, the navigation system configured to actively determine a position of the surgical instrument relative to an alert zone defined on the patient; Including, the navigation system is configured to communicate a second signal to the handpiece processor to de-energize the variable speed motor when the navigation system determines that the position of the surgical instrument has entered the alert zone; The surgical system is configured to de-energize the handheld surgical instrument and prevent re-energization of the variable speed motor while the surgical instrument remains in the alert zone until the handpiece processor receives a subsequent first signal from the switch sensor indicating that the medical professional has operated the position of the switch. Item XXIX and a rechargeable battery module removably coupled to the handheld surgical instrument, the battery module comprising: a transceiver configured to transmit and receive signals; a cell for storing electrical energy to power the variable speed motor of the handheld surgical instrument; a switch configured to control the flow of electrical energy from the cell, the switch having a conducting state configured to allow the flow of electrical energy from the cell and a non-conducting state configured to prevent the flow of electrical energy from the cell; a battery processor in communication with the transceiver and the switch, the battery processor configured to operate the switch between the powered state and the unpowered state to selectively power the handheld surgical instrument based at least in part on the signal received by the transceiver; The surgical system according to item XXVIII, comprising: Item XXX 1. A surgical system for use by a medical professional in performing surgery on a patient, the surgical system comprising: 1. A high speed bar assembly comprising: a control console having a processor; a handpiece in communication with the processor of the control console, the handpiece including an end effector and a variable speed motor that drives the end effector; a foot switch operable by the medical professional between a first position and a second position to control energization of the variable speed motor; a switch sensor configured to detect the position of the foot switch and communicate a first signal indicative of the position of the foot switch to the processor; a high speed bar assembly including: a navigation system in communication with the processor, the navigation system configured to actively determine a position of the handpiece relative to an alert zone defined on the patient; Including, the navigation system is configured to communicate a second signal to the processor to de-energize the variable speed motor when the navigation system determines that the position of the handpiece has entered the alert zone; and wherein the processor is configured to de-energize the handpiece and, while the handpiece remains in the alert zone, prevent re-energization of the variable speed motor until the processor receives a subsequent first signal from the switch sensor indicating that the medical professional has actuated the position of the foot switch. Item XXXI 10. The surgical system of claim XXX, further comprising a tactile alert device in contact with the medical professional, the tactile alert device configured to emit a physical alert perceptible to the medical professional when the high-speed surgical burr enters the alert zone. Item XXXII Item XXX: The surgical system of claim XXX, further including an audible alert device and a tactile alert device in contact with the medical professional, the audible alert device and the tactile alert device each capable of generating an alert perceptible by the medical professional when the high-speed surgical burr enters the alert zone. Item XXXIII 1. A surgical system for use by a medical professional in spinal or cranial surgery on a patient, the surgical system comprising: 1. A handheld surgical instrument configured to actuate an end effector, comprising: A variable speed motor; a trigger operable by the medical professional between a first position and a second position; a handpiece processor configured to control energization of the variable speed motor based at least in part on the position of the trigger; a handheld surgical instrument, a rechargeable battery module detachably coupled to the handheld surgical instrument, a transceiver configured to transmit and receive signals; a battery processor in communication with the transceiver, the battery processor configured to energize and de-energize the handheld surgical instrument; a rechargeable battery module including: a navigation system in communication with the battery processor via the transceiver, the navigation system configured to actively determine a position of the handheld surgical instrument relative to an alert zone defined on the patient; and Including, the navigation system is configured to communicate a first signal to the battery processor to temporarily de-energize the handheld surgical instrument when the navigation system determines that the position of the handheld surgical instrument has entered the alert zone; while the handheld surgical instrument remains in the alert zone and after the battery processor de-energizes the handheld surgical instrument; The battery processor is configured to re-energize the variable speed motor, and the navigation system is configured to communicate a second signal to the battery processor to energize or de-energize the handheld surgical instrument based on whether movement of the handheld surgical instrument is in a proximal or distal direction relative to the surgical site on the patient. Item XXXIV 1. A surgical system for use by a medical professional to perform a surgical procedure on a patient, the surgical system comprising: 1. A handheld surgical instrument configured to receive an end effector, comprising: a variable speed motor configured to rotate the end effector; a trigger operable by the medical professional between a first position and a second position; a trigger sensor configured to detect the position of the trigger and output a first signal indicative of the position of the trigger; a handpiece processor configured to control energization of the variable speed motor based at least in part on the first signal from the trigger sensor indicative of the position of the trigger; a handheld surgical instrument, a navigation system in communication with the processor, the navigation system configured to define an alert zone on the patient, actively determine a position of the surgical instrument relative to the alert zone, and communicate a second signal to the handpiece processor to stop the variable speed motor when the trigger sensor indicates that the trigger is in the second position and the navigation system determines that the handheld surgical instrument has entered the alert zone; Including, a surgical system, wherein the handpiece processor is configured to restart the variable speed motor upon receiving a subsequent first signal from the trigger sensor indicating that the medical professional has operated the trigger to move the trigger from the second position to the first position and back to the second position while the handheld surgical instrument remains within the alert zone. Item XXXV Item XXXIV: The surgical system of claim XXXIV, wherein when the variable speed motor is restarted while the handheld surgical instrument remains in the alert zone, the navigation system is configured to communicate a third signal to the handpiece processor to stop the variable speed motor when the navigation system determines that the handheld surgical instrument has moved a predetermined distance proximally toward the patient's surgical site (the alert zone). Item XXXVI Item XXXIV: The surgical system of claim XXXIV, wherein when the variable speed motor is restarted while the handheld surgical instrument remains in the alert zone, the navigation system is configured to communicate a fourth signal to the handpiece processor to continue activation of the variable speed motor when the navigation system determines that the handheld surgical instrument has moved distally from the patient's surgical site (the alert zone). Item XXXVII 1. A surgical system for use by a medical professional in spinal or cranial surgery on a patient, the surgical system comprising: 1. A handheld surgical instrument configured to receive an end effector, comprising: A variable speed motor; a trigger operable by the medical professional between a first position and a second position to start and stop the variable speed motor; a processor configured to control energization of the variable speed motor; a handheld surgical instrument, a navigation system in communication with the processor, the navigation system configured to allow the medical professional to define a target axis on the patient and an instrument inspection distance threshold; Including, the navigation system is configured to determine an actual axis of the handheld surgical instrument relative to the target axis, determine a position of the handheld surgical instrument relative to the target depth, and compare the result to an instrument check distance threshold; When the navigation system determines that the position of the handheld surgical instrument is closer to the target depth than the instrument inspection distance threshold and the actual axis of the handheld surgical instrument is misaligned with the target axis, the navigation system is configured to communicate a first signal to the processor to prevent energization of the variable speed motor; A surgical system, wherein when the navigation system determines that the position of the handheld surgical instrument is farther from the target depth than the instrument inspection distance threshold, the navigation system does not cause the processor to prevent energization of the variable speed motor, regardless of whether the actual axis of the handheld surgical instrument is misaligned with the target axis. Item XXXVIII Item XXXVII. The surgical system of claim XXXVII, wherein, while the trigger is in the second position, the navigation system is configured to communicate a fifth signal to the processor to stop the variable speed motor when the navigation system determines that the handheld surgical instrument is positioned on the target axis and has reached the target depth to activate the variable speed motor. Item XXXIX 1. A surgical system for use by a medical professional in spinal or cranial surgery on a patient, the surgical system comprising: 1. A handheld surgical instrument configured to receive an end effector, comprising: A handpiece and a variable speed motor disposed within the handpiece; a trigger operable by the medical professional to start and stop the variable speed motor; a switch operable by the medical professional between a first position and a second position to control the speed of the variable speed motor; a processor configured to control energization of the variable speed motor; a handheld surgical instrument, a navigation system in communication with the processor, the navigation system configured to determine whether the switch is in the first position or the second position; Including, A surgical system, wherein the navigation system is configured to communicate a signal to the processor that controls energization of the variable speed motor based on the switch being in the appropriate position and the type of end effector coupled to the handheld surgical instrument. Item XL the navigation system is configured to communicate the signal to the processor to stop the variable speed motor when the navigation system identifies the switch as being in an incorrect position for the type of end effector coupled to the handheld surgical instrument; Item XXXIX: The surgical system of claim XXXIX, wherein the navigation system is configured to communicate the signal to the processor to activate the variable speed motor when the navigation system identifies that the switch is in the correct position for the type of end effector coupled to the surgical instrument. Item XLI the handheld surgical instrument further includes a tracking device coupled to the switch; The surgical system of claim XXXIX or XL, wherein the navigation system is configured to determine whether the switch is in the first position or the second position based on the position of the tracking device. Item XLII the handheld surgical instrument further includes a battery module; The surgical system of any one of items XXXIX to XLI, wherein the processor is disposed within the battery module. Item XLIII 1. A surgical system for use by a medical professional in spinal or cranial surgery on a patient, the surgical system comprising: 1. A handheld surgical instrument assembly comprising: A handpiece and one of a first end effector or a second end effector, each of the first end effector and the second end effector being removably coupleable to the handpiece; a variable speed motor disposed within the handpiece; any vibrating feedback device; a processor configured to control energization of the variable speed motor and / or vibration of the feedback device; a handheld surgical instrument assembly including: a navigation system in communication with the processor, the navigation system configured to define a first alert zone on the patient based at least in part on the first end effector and a second alert zone on the patient based at least in part on the second end effector; Including, when the first end effector couples to the handpiece, the navigation system is configured to communicate a first signal to the processor to control energization of the variable speed motor or vibrate the feedback device based at least in part on a position of the first end effector relative to the first alert zone; A surgical system, wherein when the second end effector is coupled to the handpiece, the navigation system is configured to control energization of the variable speed motor or communicate a signal to the processor to vibrate the feedback device based at least in part on the position of the second end effector relative to the second alert zone. Item XLIV The surgical system of item XLIII, wherein the navigation system is configured to actively determine the position of the handheld surgical instrument relative to the alert zone and communicate the position to the processor. Item XLV Item XLIII. The surgical system of claim XLIII, wherein the navigation system is configured to communicate a signal to the processor to stop the variable speed motor when the navigation system determines that the first end effector has entered the first alert zone or the second end effector has entered the second alert zone. Item XLVI The handheld surgical instrument further comprises: a footswitch in electrical communication with the processor; a feedback device coupled to the foot switch; The surgical system according to item XLIII, comprising: Item XLVII The surgical system of item XLIII, wherein the navigation system is configured to allow the medical professional to input the type of the first end effector or the second end effector to be coupled to the handheld surgical instrument. Item XLVIII The handheld surgical instrument assembly includes a battery module; The surgical system of any one of items XLIII to XLVII, wherein the optional feedback device is disposed within the battery module. Item XLIX 1. A surgical system for use by a medical professional in spinal or cranial surgery on a patient, the surgical system comprising: 1. A high speed bar assembly comprising: a control console having a processor; a handpiece in communication with the processor of the control console; one of a first end effector or a second end effector, each of the first end effector and the second end effector being removably coupleable to the handpiece; a variable speed motor disposed within the handpiece; any feedback device; Including, a high speed bar assembly, the processor configured to control energization of the variable speed motor and / or vibration of the feedback device; a navigation system in communication with the processor, the navigation system configured to define a first alert zone on the patient based at least in part on the first end effector and a second alert zone on the patient based at least in part on the second end effector; Including, when the first end effector couples to the handpiece, the navigation system is configured to communicate a first signal to the processor to control energization of the variable speed motor or activate the feedback device based at least in part on a position of the first end effector relative to the first alert zone; A surgical system, wherein when the second end effector is coupled to the handpiece, the navigation system is configured to control energization of the variable speed motor or communicate a signal to the processor to activate the feedback device based at least in part on the position of the second end effector relative to the second alert zone. Item L 49. The surgical system of claim XLIX, wherein the optional feedback device includes a tactile alert device in contact with the medical professional and configured to emit a physical alert perceptible to the medical professional when the high-speed surgical burr enters the alert zone. Item LI 10. The surgical system of claim XLIX, wherein the optional feedback devices include an audible alert device and a tactile alert device in contact with the medical professional, the audible alert device and the tactile alert device each capable of generating an alert perceptible by the medical professional when the high-speed surgical burr enters the alert zone. Item LII the high speed bar assembly further includes a foot switch coupled to the control console, the foot switch movable between a first position and a second position to control energization of the variable speed motor; The surgical system of item XLIX or L, wherein the medical professional can disable any of the feedback devices by operating the foot switch in a predetermined pattern within a predetermined period of time. Item LIII 1. A method of navigating a surgical instrument using a surgical navigation system during a medical procedure on a patient, the surgical instrument including a handpiece, an end effector coupled to the handpiece, a variable speed motor selectively driving the end effector, and a processor controlling energization of the variable speed motor, the method comprising: Choosing a medical implant and identifying a location within patient data stored in the surgical navigation system to place the medical implant in the patient, the surgical navigation system being configured to define an alert zone based on the selected medical implant and the identified location to place the medical implant; tracking the position of the surgical instrument using the surgical navigation system; when the navigation system determines that the surgical instrument has entered the defined alert zone, the surgical navigation system sends a signal to the processor to stop the variable speed motor; A method comprising: Item LIV The method of claim LIII, further comprising manipulating the alert zone defined in the surgical navigation system according to a preference of the medical professional. Item LV The method of any one of claims LIII to LIV, wherein the method further includes coupling a first end effector to the handpiece, and the surgical navigation system is configured to identify the first end effector and define a first alert zone based at least in part on the first end effector. Item LVI The method of any one of items LIII-LV, wherein the method further includes coupling a second end effector to the handpiece, and the surgical navigation system is configured to identify the second end effector and define a second alert zone based at least in part on the second end effector. Item LVII The method of any one of items LIII to LVI, further comprising activating an alert device when the surgical navigation system determines that the surgical instrument has entered the defined alert zone. Item LVIII The method of any one of items LIII to LVII, further comprising the step of assigning an alert type to each of the defined alert zones. Item LIX identifying a first end effector coupled to the handpiece, the surgical navigation system being configured to define a first alert zone based at least in part on the first end effector; decoupling the first end effector from the handpiece; coupling a second end effector to the handpiece, wherein the surgical navigation system is configured to identify the second end effector and define a second alert zone based at least in part on the second end effector; The method according to item LIII, further comprising: Item LX identifying a first end effector coupled to the handpiece, the surgical navigation system being configured to define a first alert zone based at least in part on the first end effector; applying the first end effector to a location in biological tissue where the medical implant is to be placed; when the navigation system determines that the surgical instrument has entered the first alert zone, the surgical navigation system sends a signal to the processor to stop the variable speed motor; decoupling the first end effector from the handpiece; coupling a second end effector to the handpiece, wherein the surgical navigation system is configured to identify the second end effector and define a second alert zone based at least in part on the second end effector; applying the second end effector to a location in biological tissue where the medical implant is to be placed; when the navigation system determines that the surgical instrument has entered the second alert zone, the surgical navigation system sends a signal to the processor to stop the variable speed motor; The method according to item LIII, further comprising: Item LXI 1. A surgical system for use by a medical professional in performing surgery on a patient, the surgical system comprising: 1. A high speed bar assembly comprising: a control console having a processor; a handpiece in communication with the processor of the control console, the handpiece including an end effector and a variable speed motor that drives the end effector; a foot switch operable by the medical professional between a first position and a second position to control energization of the variable speed motor; a high speed bar assembly including: a navigation system in communication with the processor, the navigation system configured to actively determine a position of the handpiece relative to an alert zone defined on the patient; Including, the navigation system is configured to communicate a first signal to the processor to temporarily de-energize the handpiece when the navigation system determines that the position of the handpiece has entered the alert zone; the handpiece remains in the alert zone when the processor temporarily de-energizes the handpiece; When the variable speed motor is re-energized, the navigation system is configured to communicate a second signal to the processor to energize or de-energize the handpiece based on whether movement of the handpiece is in a proximal or distal direction relative to the surgical site on the patient. Item LXII 1. A surgical instrument assembly for use in conjunction with a navigation system configured to enable a medical professional to define an alert zone on a patient to assist the medical professional in performing a procedure on the patient, the surgical instrument assembly comprising: a control console including a control processor in communication with the navigation system; a high-speed surgical burr assembly having a variable speed motor in communication with the control processor, the variable speed motor configured to rotate a burr; a foot switch movable between a first position and a second position to energize the variable speed motor of the high-speed surgical burr; a footswitch sensor in communication with the control processor, the footswitch configured to detect the position of the footswitch and communicate a first signal indicative of the position of the footswitch to the control processor; a tactile alert device coupled to the foot switch and in communication with the control processor, the tactile alert device positioned on the foot switch such that the tactile alert device is in contact with the medical professional when the medical professional depresses the foot switch to operate the high-speed surgical burr; Including, the navigation system is configured to actively determine a position of the high-speed surgical burr relative to the patient; the navigation system is configured to send a second signal to the control processor when the high-speed surgical burr enters the alert zone, the second signal activating the tactile alert device to emit a physical alert perceptible to the medical professional; and wherein, while the high-speed surgical burr is still within the alert zone, the processor is configured to deactivate the alert device upon receiving a subsequent first signal from the foot switch sensor indicating that the medical professional has moved the foot switch between the first position and the second position a predetermined number of times within a predetermined time period. Item LXIII 1. A surgical system for use by a medical professional in performing surgery on a patient, the surgical system comprising: 1. A high speed bar assembly comprising: a control console having a processor; a handpiece in communication with the processor of the control console, the handpiece including an end effector and a variable speed motor that drives the end effector; a foot switch operable by the medical professional between a first position and a second position to control energization of the variable speed motor; a high speed bar assembly including: a navigation system in communication with the processor, the navigation system configured to actively determine a position of the handpiece relative to an alert zone defined on the patient; Including, The navigation system is configured to communicate a first signal to the processor in response to the end effector entering the alert zone, the first signal causing the processor to adjust a torque map to which the handpiece is powered. Item LXIV 1. A surgical system for use by a medical professional in spinal or cranial surgery on a patient, the surgical system comprising: 1. A handheld surgical instrument configured to receive an end effector, comprising: A handpiece and a variable speed motor disposed within the handpiece; a trigger operable by the medical professional to start and stop the variable speed motor; a switch operable by the medical professional between a first position and a second position to control the speed of the variable speed motor; a processor configured to control energization of the variable speed motor; a handheld surgical instrument, a navigation system in communication with the processor, the navigation system configured to determine whether the switch is in the first position or the second position using machine vision; Including, A surgical system, wherein the navigation system is configured to communicate a signal to the processor that controls energization of the variable speed motor based on the switch being in the appropriate position and the type of end effector coupled to the handheld surgical instrument. Item LXV the handheld surgical instrument further includes a tracking device coupled to the switch; The surgical system of claim LXIV, wherein the navigation system is configured to determine whether the switch is in the first position or the second position based on the position of the tracking device. Item LXVI the handheld surgical instrument further includes a battery module; The surgical system of item LXIV or LXV, wherein the processor is disposed within the battery module. Item LXVII 10. A surgical navigation system for use in guiding surgical instruments to perform a medical procedure, substantially as described in any preceding paragraph.

[0169] Several embodiments have been set forth in the foregoing description. However, the embodiments discussed herein are not intended to be exhaustive or to limit the invention to any particular form. The terminology used herein is for purposes of description rather than limitation. Many modifications and variations are possible in light of the above teachings, and the invention may be practiced otherwise than as specifically described.

Claims

**Claim 1** A surgical system configured to enable a medical professional performing surgery on a patient to define an alert zone associated with a critical structure of the patient in a known coordinate system, comprising: a navigation system; a control console having a control processor communicating with the navigation system; a high-speed surgical instrument having a bar and a variable-speed motor communicating with the control processor, the variable-speed motor rotating the bar at a first cutting speed greater than 70,000 revolutions per minute and at a second cutting speed less than 70,000 revolutions per minute and greater than 60,000 revolutions per minute; a foot switch for controlling the operation of the variable-speed motor of the high-speed surgical instrument communicating with the control processor; and; the navigation system actively determines the position of the bar relative to the alert zone in the known coordinate system; when the navigation system determines that the bar has entered the alert zone, the navigation system sends a signal to the control processor to control the variable-speed motor of the high-speed surgical instrument to switch the rotation of the bar from the first cutting speed to the second cutting speed; due to the switching of the bar from the first cutting speed to the second cutting speed, a perceptible change occurs when the bar switches from the first cutting speed to the second cutting speed, and the medical professional is notified that the bar has entered the alert zone; a surgical system. **Claim 2** The foot switch is movable between a first position and a second position; the variable-speed motor stops when the foot switch is in the first position and rotates the bar at at least 60,000 revolutions per minute when the foot switch is not in the first position; The surgical system according to claim 1. **Claim 3** After receiving the signal from the navigation system for controlling the variable-speed motor from the first cutting speed to the second cutting speed in response to the bar entering the alert zone, the control processor controls the variable-speed motor of the high-speed surgical instrument and returns the rotation of the bar to the first cutting speed in response to the movement of the foot switch to the first position by the user and a change in the position of the foot switch to a position other than the first position; The surgical system according to claim 2. **Claim 4** The system further includes a tactile alert device that is touched by the medical expert and gives a tactile alert that can be perceived by the medical expert when the bar enters the alert zone. The tactile alert device is connected to the foot switch. The tactile alert device includes a motor that vibrates when activated. The vibration of the motor provides a physical alert that can be felt by the foot of a user touching the foot switch that controls the operation of the variable speed motor of the high-speed surgical instrument. The surgical system according to any one of claims 1 to 3.

5. The navigation system receives a first boundary selectable by a user and a depth selectable by the user, and projects a second boundary at the depth selectable by the user from the first boundary. The first boundary and the second boundary define a volume representing the alert zone. The surgical system according to any one of claims 1 to 4.

6. The system further includes at least one of an audible alert device and a tactile alert device touched by the medical expert. The audible alert device and the tactile alert device can each give an alert that is perceived by the medical expert when the bar enters the alert zone. The alert zone has a first alert zone and a second alert zone. The navigation system is configured such that a user can assign one of a first notification type and a second notification type to either the first alert zone, the second alert zone, or a combination of both alert zones. The navigation system controls one of the audible alert device and the tactile alert device based on the position of the bar, the first alert zone, the second alert zone, and the first notification type or the second notification type assigned to any one of the first alert zone and the alert zone. The surgical system according to any one of claims 1 to 5.

7. The navigation system has a graphical user interface (GUI) having a graphic regarding the alert zone. The alert zone is selectable by operating the graphical user interface (GUI). The graphical user interface (GUI) provides a user-selectable icon that stops at least one of the audible alert device and the tactile alert device after the bar enters the alert zone. The control processor activates at least one of the stopped audible alert device and the tactile alert device again based on the position of the bar being outside the alert zone for a predetermined time and then returning to the alert zone. The surgical system according to claim 6.

8. The surgical system further includes at least one of an audible alert device capable of generating a first notification and a tactile alert device capable of generating a second notification. The alert zone has a first boundary selectable by the user and a second boundary selectable by the user. The navigation system is configured such that the user can assign one of the first notification and the second notification to either the first boundary or the second boundary. The navigation system controls one of the audible alert device and the tactile alert device based on the position of the bar relative to the first boundary or the second boundary, causing one of the first notification or the second notification to occur. The surgical system according to any one of claims 1 to 7.

9. The surgical system according to any one of claims 1 to 8, wherein the navigation system defines a boundary that at least partially defines the alert zone based at least in part on a segmentation algorithm.

10. The navigation system defines a first boundary with respect to an important structure of the patient and projects a second boundary at a first distance from the first boundary, and the first boundary and the second boundary define a volume representing the alert zone. When the bar enters the volume representing the alert zone, the navigation system sends a signal to the control processor to control the variable speed motor of the high-speed surgical instrument to switch the rotation of the bar from the first cutting speed to the second cutting speed. The surgical system according to any one of claims 1 to 9.

11. The surgical system according to claim 10, wherein the navigation system defines the first boundary based on a planned posture of the implant selected for insertion into the patient, and defines the second boundary at a first distance from the first boundary along an axis of the implant.

12. The surgical system according to any one of claims 1 to 11, wherein when the navigation system is unable to determine the position of the bar with respect to the patient over a predetermined time, the navigation system further sends a second signal to the control processor to stop the variable speed motor of the high-speed surgical instrument until the navigation system is thereafter able to determine the position of the bar with respect to the patient.

13. The foot switch is movable between a first position and a second position, and the variable speed motor stops when the foot switch is in the first position and rotates the bar when the foot switch is not in the first position. The tactile alert device stops in response to movement of the foot switch by the user to the first position and change of the position of the foot switch to a position other than the first position while the bar is still within the alert zone. The surgical system according to claim 4.

14. The surgical system according to claim 3, wherein the control processor triggers the variable speed motor of the high-speed surgical instrument again based on the bar being outside the alert zone for a predetermined time and then entering the alert zone again, and switches the rotation of the bar from the first cutting speed to the second cutting speed.

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