Systems and methods for providing haptic guidance

Abstract

To provide surgical systems that facilitate joint replacement procedures.SOLUTION: A method includes defining a virtual object, and defining a first point and a second point associated with a virtual representation of a surgical tool. Movement of the virtual representation of the surgical tool corresponds to movement of the surgical tool in real space. The method includes controlling a robotic device coupled to the surgical tool to constrain the first point to the virtual object, determining that the first point is at a threshold position along the virtual object, and controlling the robotic device to guide the second point to the virtual object.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] This application claims the benefit of and priority to U.S. Provisional Application No. 62 / 908,890, filed October 1, 2019, the entire disclosure of which is incorporated herein by reference. [Background technology]

[0002] The present disclosure relates generally to orthopedic surgical systems, such as surgical systems that facilitate joint replacement. Joint replacement (arthroplasty) is widely used to treat osteoarthritis and other damage to a patient's joints by replacing a portion of the joint with a prosthetic component. Joint replacement may include a procedure to replace a hip, knee, shoulder, or other joint with one or more prosthetic components.

[0003] One possible tool used in joint arthroplasty surgery is a robotic-assisted surgical system. A robotic-assisted surgical system typically includes a robotic device used to prepare the patient's anatomy to receive the implant, a tracking system configured to monitor the location of the robotic device relative to the patient's anatomy, and a computing system configured to monitor and control the robotic device. In various forms, a robotic-assisted surgical system autonomously performs surgical tasks, provides force feedback to a user who manipulates the surgical device to complete the surgical task, enhances the surgeon's dexterity and precision, and / or provides other navigational cues that facilitate safe and accurate surgery.

[0004] A surgical plan is typically established prior to performing a surgical procedure with a robotic-assisted surgical system. Based on the surgical plan, the surgical system guides, controls, or limits the movement of surgical tools during portions of the surgical procedure. The guidance and / or control of the surgical tools serves to assist the surgeon during the implementation of the surgical plan. [Brief description of the drawings]

[0005] [Figure 1]1 is a perspective view of a femur prepared to receive an implant component according to an exemplary embodiment; FIG. [Diagram 2] 1 is an illustration of a surgical system, in accordance with an exemplary embodiment. [Diagram 3] 3 is a flowchart of a first process that may be performed by the surgical system of FIG. 2 according to an exemplary embodiment. [Figure 4] 3 is a flowchart of a second process that may be performed by the surgical system of FIG. 2 according to an exemplary embodiment. [Diagram 5] FIG. 5 is an illustration of the process of FIG. 4 in accordance with an example embodiment. [Figure 6] 3 is a flowchart of a third process that may be performed by the surgical system of FIG. 2 according to an exemplary embodiment. [Figure 7] 7 is an illustration of a virtual control object that may be used in the process of FIG. 6 in accordance with an example embodiment. [Figure 8] 11 is a flowchart of a fourth process that may be performed by the surgical system of FIG. 2 in accordance with an exemplary embodiment. [Figure 9] 11 is a flowchart of a fifth process that may be performed by the surgical system of FIG. 2 in accordance with an exemplary embodiment. [Figure 10] 10 is an illustration of a virtual control object that may be used in the process of FIG. 9 in accordance with an exemplary embodiment. [Figure 11] 11 is a flowchart of a sixth process that may be performed by the surgical system of FIG. 2 according to an exemplary embodiment. [Figure 12] 11 is a flowchart of a seventh process that may be performed by the surgical system of FIG. 2 in accordance with an exemplary embodiment. [Figure 13] 11 is a flowchart of an eighth process that may be performed by the surgical system of FIG. 2 according to an exemplary embodiment. Summary of the Invention

[0006] One embodiment of the present disclosure is a method for controlling a robotic device. The method includes defining a virtual object and defining a first point and a second point associated with a virtual representation of a surgical tool. Movement of the virtual representation of the surgical tool corresponds to movement of the surgical tool in real space. The method includes controlling a robotic device coupled to the surgical tool to constrain the first point to the virtual object, determining that the first point is at a threshold position along the virtual object, and controlling the robotic device to guide the second point to the virtual object.

[0007] Another embodiment of the present disclosure is a system including a robotic device and a processing circuit in communication with the robotic device. The processing circuit can be configured to define a virtual object and to define a first point and a second point associated with a virtual representation of a surgical tool. The processing circuit is configured such that a movement of the virtual representation of the surgical tool corresponds to a movement of the surgical tool in real space. The processing circuit is further configured to control a robotic device coupled to the surgical tool to constrain the first point to the virtual object, determine that the first point is at a threshold position along the virtual object, and control the robotic device to guide the second point to the virtual object.

[0008] Another embodiment of the present disclosure is a method of operating a robotic device to which a tool is coupled, the method including controlling the robotic device to constrain a surgical tool based on a first haptic object, receiving a signal and a user-defined direction, and adjusting a haptic control interaction in response to the signal by extending the first haptic object in the user-defined direction.

[0009] Another embodiment of the present disclosure is a system including a robotic device and a processing circuit in communication with the robotic device configured to control the robotic device to constrain a surgical tool based on a first haptic object, receive a signal and a user-defined direction, and adjust a haptic control interaction in response to the signal by extending the first haptic object in the user-defined direction.

[0010] Another embodiment of the present disclosure is a method of operating a robotic device to which a tool is coupled, the method including controlling the robotic device to constrain the tool based on a first haptic object, receiving a signal and a user-defined direction, and adjusting a haptic control interaction in response to the signal by adjusting a virtual dimension of the tool.

[0011] Another embodiment of the present disclosure is a system including a robotic device and a processing circuit in communication with the robotic device configured to control the robotic device to constrain a tool based on a first haptic object, receive a signal and a user-defined direction, and adjust a haptic control interaction in response to the signal by adjusting a virtual dimension of the tool.

[0012] Another embodiment of the present disclosure is a method of operating a robotic device, the method including tracking movement of a tool coupled to the robotic device, determining a direction of movement of the tool, determining whether the direction of movement is towards a virtual control object, and in response to determining that the direction of movement is towards the virtual control object, operating the robotic device. and controlling the tool to guide the tool to the virtual control object.

[0013] Another embodiment of the present disclosure is a system including a robotic device and a processing circuit in communication with the robotic device configured to receive tracking data indicative of movement of a tool coupled to the robotic device, determine a direction of movement of the tool, determine whether the direction of movement is toward a virtual control object, and, in response to determining that the direction of movement is toward the virtual control object, control the robotic device to guide the tool toward the virtual control object.

[0014] Another embodiment of the present disclosure is a method of operating a robotic device, the method including tracking a tool coupled to the robotic device, controlling the robotic device to constrain the tool within a virtual control object, defining a zone of the virtual object, determining that the tool is within the zone, and controlling the robotic device to resist movement of the tool within the zone.

[0015] Another embodiment of the present disclosure is a system including a robotic device and a processing circuit in communication with the robotic device configured to control the robotic device to constrain a tool within a virtual control object, define a zone of the virtual object, determine when the tool is within the zone, and control the robotic device to resist movement of the tool within the zone.

[0016] Another embodiment of the present disclosure is a method of operating a robotic device to which a tool is coupled, the method including constraining, by the robotic device, the tool to a virtual control object, detecting a force on the tool in approximately a predetermined direction, determining whether the force in approximately the predetermined direction exceeds a threshold force, and, in response to determining that the force in approximately the predetermined direction exceeds the threshold force, controlling the robotic device to enable movement of the tool out of the virtual control object.

[0017] Another embodiment of the present disclosure is a system that includes a robotic device and a processing circuit in communication with the robotic device configured to control the robotic device to constrain a tool to a virtual control object, detect a force on the tool in approximately a predetermined direction, determine whether the force in approximately the predetermined direction exceeds a threshold force, and, in response to determining that the force in approximately the predetermined direction exceeds the threshold force, control the robotic device to enable removal of the tool from the virtual control object. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] Preferred embodiments of the present invention are now illustrated in the drawings. An effort has been made to use the same or similar reference numerals throughout the drawings to represent the same or similar parts. Although this specification primarily depicts a robotic arm for orthopedic joint replacement surgery, it should be understood that the subject matter described herein is applicable to other types of robotic systems, including those used in non-surgical applications, as well as procedures targeting other anatomical regions (e.g., spinal or dental procedures).

[0019] Referring now to FIG. 1, a femur 101 is shown modified during a knee arthroplasty procedure, according to an exemplary embodiment. As shown in FIG. 1, the femur 101 has been modified by a number of planar cuts. In the example shown, the femur 100 has been modified by five substantially planar cuts to create five substantially planar surfaces: a distal surface 102, a posterior chamfer surface 104, a posterior surface 106, an anterior surface 108, and an anterior chamfer surface 110. A sagittal saw or other surgical tool (e.g., a surgical tool coupled to a robotic device, as in the example described below) may be used to achieve the planar surfaces. The planar surfaces 102-110 define a femoral implant structure. The planes 102-110 are created to mate with corresponding surfaces of the implant components. The location and angular orientation of the planes 102-110 may determine the alignment and positioning of the implant components. Thus, the surgical tools may be operated to create the planes 102-110 with high precision to improve the outcome of the joint replacement surgery.

[0020] As shown in FIG. 1 , the femur 101 is also modified to have a pair of pilot holes 120. The pilot holes 120 extend into the femur 101 and are created such that the pilot holes 120 can receive screws, protrusions extending from a surface of an implant component, or other structures configured to facilitate coupling of an implant component to the femur 101. A drill, a spherical burr, or other surgical tool as described below may be used to create the pilot holes 120. The pilot holes 120 may have a pre-planned location, orientation, and depth to facilitate safe coupling of the implant component to the bone in a desired location and orientation. In some cases, the pilot holes 120 are planned to intersect dense areas of the bone and / or avoid other implant components and / or sensitive anatomical features. Thus, the surgical tools may be operated to create the pilot holes 120 with high precision to improve the outcome of the joint replacement surgery.

[0021] In some embodiments, the systems and methods described herein provide robotic assistance to create the planes 102-110 and pilot holes 120. It should be understood that the creation of the five planar cuts and two cylindrical pilot holes as shown in FIG. 1 is merely an example, and that the systems and methods described herein may be adapted in various embodiments to plan and facilitate the creation of any number of planar or non-planar cuts, any number of pilot holes, any combination thereof, etc., to prepare any bone and / or joint. For example, in a hip arthroplasty procedure or a shoulder arthroplasty procedure, a spherical burr may be used in accordance with the systems and methods herein to ream a curved hole configured to receive a curved implant cup. Additionally, in other embodiments, the systems and methods described herein may be used to facilitate placement of an implant component relative to a bone (e.g., facilitate fixation of a cup implant in a hip arthroplasty procedure). Many such surgical and non-surgical implementations are within the scope of the present disclosure.

[0022] Referring now to FIG. 2, an exemplary embodiment illustrates a surgical system 200 for orthopaedic surgery. Generally, the surgical system 200 is configured to facilitate the planning and execution of a surgical plan, for example, to facilitate a joint-related procedure. As shown in FIG. 2, the surgical system 200 is set up to treat a leg 202 of a patient 204 sitting or lying on a table 205. In the illustration shown in FIG. 2, the leg 202 includes a femur 206 (e.g., femur 101 of FIG. 1) and a tibia 208 between which a prosthetic knee implant is to be implanted throughout a knee arthroscopic procedure. In another scenario, the surgical system 200 is set up to treat a patient's hip (i.e., the patient's femur and pelvis). Additionally, in other scenarios, the surgical system 200 is set up to treat a patient's shoulder, i.e., to facilitate replacement and / or augmentation of shoulder joint components (e.g., to facilitate placement of humeral components, glenoid components, and graft or implant augments). A variety of other anatomical regions and procedures are also possible. To facilitate the procedures, the surgical system 200 includes a robotic device 220, a tracking system 222, and a computing system 224.

[0023] The robotic device 220 is configured to modify a patient's anatomy (e.g., the femur 206 of the patient 204) under the control of a computing system 224. One embodiment of the robotic device 220 is a haptic device. "Haptic" refers to the sense of touch, and the field of haptics relates specifically to human-interactive devices that provide feedback to an operator. The feedback may include, for example, tactile sensations such as vibrations. The feedback may also include force ( The haptics may include providing a user with a force (such as a positive force or a resistance to movement) to guide or limit the manipulation of a device to a user of the device. For example, a haptic device may be coupled to a surgical tool that can be manipulated by a surgeon performing a surgical procedure. The manipulation of the surgical tool by the surgeon can be guided or limited by using haptics to provide feedback to the surgeon during manipulation of the surgical tool.

[0024] Another embodiment of the robotic device 220 is an autonomous or semi-autonomous robot. "Autonomous" refers to the ability of the robotic device to operate independently or semi-independently from human control by gathering information about its situation, determining a course of action, and automatically executing that course of action. For example, in such an embodiment, the robotic device 220 in communication with the tracking system 222 and the computing system 224 may autonomously complete the sequence of femoral cuts described above without direct human intervention.

[0025] The robotic device 220 includes a base 230, a robotic arm 232, and a surgical tool 234, and is communicatively coupled to the computing system 224 and the tracking system 222. The base 230 provides a movable foundation for the robotic arm 232, allowing the robotic arm 232 and the surgical tool 234 to be repositioned relative to the patient 204 and table 205 as needed. The base 230 may also include power systems, computing elements, motors, and other electronic or mechanical systems necessary for the robotic arm 232 and the surgical tool 234 to function, as described below.

[0026] The robotic arm 232 is configured to support the surgical tool 234 and provide forces as commanded by the computing system 224. In some embodiments, the robotic arm 232 allows a user to manipulate the surgical tool and provides force feedback to the user. In such embodiments, the robotic arm 232 includes joints 236 and mounts 238, including motors, actuators, or other mechanisms, that are configured to allow the user to freely translate and rotate the robotic arm 232 and surgical tool 234 through acceptable poses, while providing force feedback to constrain or prevent some movements of the robotic arm 232 and surgical tool 234, as commanded by the computing system 224. As described in more detail below, the robotic arm 232 thus allows the surgeon to control the surgical tool 234 at will within a controlled object while providing force feedback (e.g., vibrations, forces to prevent or resist boundary penetration) along the boundaries of that object. In some embodiments, the robotic arm is configured to automatically move the surgical tool into a new pose as needed, without direct user manipulation, as commanded by the computing system 224 to position the robotic arm and / or complete a particular surgical task (e.g., including cutting the femur 206).

[0027] The surgical tool 234 is configured to cut, serrate, grind, drill, partially resect, reshape, and / or otherwise modify bone, or to constrain / limit the movement of a device used to cut, serrate, grind, drill, partially resect, reshape, and / or otherwise modify bone. The surgical tool 234 may be any suitable tool and may be one of a number of tools that are interchangeably connectable to the robotic device 220. For example, as shown in FIG. 2, the surgical tool 234 includes a spherical burr 244. In other examples, the surgical tool may also be a sagittal saw, for example, with a blade aligned parallel to the tool axis or perpendicular to the tool axis. The surgical tool may also be a sagittal saw, for example, with a blade aligned parallel to the tool axis or perpendicular to the tool axis. It may be a drill with a rotating bit aligned parallel or perpendicular to the tool axis. In various embodiments, the surgical tool 234 may be, for example, a jig, drill guide, cutting guide, etc. configured to have a saw, drill, or other instrument inserted therethrough. The surgical tool 234 may also be a holding arm or other support configured to hold an implant component (e.g., cup 28a, implant augment, etc.) in place while the implant component is screwed to bone, glued (e.g., cemented) to bone or other implant component, or otherwise set in a preferred location. In some embodiments, the surgical tool 234 is an anchoring tool configured to provide an anchoring force to the cup implant to facilitate fixation of the cup implant to the pelvis at a planned location and orientation.

[0028] The tracking system 222 is configured to track the patient's anatomical structures (e.g., the femur 206 and the tibia 208) and the robotic device 220 (i.e., the surgical tool 234 and / or the robotic arm 232) to enable control of the surgical tool 234 coupled to the robotic arm 232, to determine the position and orientation or other results of modifications made by the surgical tool 234, and to enable a user to view the bones (e.g., the femur 206, the tibia 208, the pelvis, the humerus, the scapula, etc., applicable to various procedures), the surgical tool 234, and / or the robotic arm 232 on a display of the computing system 224. More specifically, the tracking system 222 determines the position and orientation (i.e., pose) of objects (e.g., the surgical tool 234, the femur 206) relative to a coordinate system and tracks (i.e., continuously determines) the pose of the objects during the surgical procedure. According to various embodiments, the tracking system 222 may be any type of navigation system including a non-mechanical tracking system (e.g., an optical tracking system), a mechanical tracking system (e.g., tracking based on measuring the relative angles of the joints 236 of the robotic arm 232), or any combination of non-mechanical and mechanical tracking systems.

[0029] In the embodiment shown in FIG. 2, the tracking system 222 includes an optical tracking system. Thus, the tracking system 222 includes a first fiducial 240 coupled to the tibia 208, a second fiducial 241 coupled to the femur 206, a third fiducial 242 coupled to the base 230, one or more fiducials coupled to the surgical tool 234, and a detection device 246 configured to detect three-dimensional positions of the fiducials (i.e., markers on the fiducials 240-242). The fiducials 240, 241 may be coupled to other bones (e.g., the pelvis and femur in a hip arthroplasty procedure) as appropriate for various procedures. The detection device 246 may be an optical detector, such as a camera or an infrared sensor. The fiducials 240-242 include fiducials that are markers, configured to be clearly visible to the optical detector and / or configured to be easily detectable by an image processing system using data from the optical detector, for example, by being highly reflective to infrared radiation (e.g., infrared radiation emitted by elements of the tracking system 222). The stereoscopic vision of the cameras in the detection device 246 allows the position of each fiducial in three-dimensional space to be determined by a triangulation approach. Each fiducial has a geometric relationship to a corresponding object, whereby tracking of the fiducials allows tracking of the object (e.g. tracking of the second fiducial tree 241 allows the tracking system 222 to track the femur 206), and the tracking system 222 may be configured to perform a registration process to determine or verify this geometric relationship. The unique arrangement of the fiducials of the fiducial trees 240-242 (i.e. the fiducials of the first fiducial tree 240 are arranged in a different geometry than the fiducials of the second fiducial tree 241) allows the fiducial trees, and thus the tracked objects, to be distinguished from each other.

[0030] Using the tracking system 222 of FIG. 2 or some other approach to surgical navigation and tracking, the surgical system 200 can determine the position of the surgical tool 234 relative to the patient's anatomical features (e.g., the femur 206), which can be used to , to modify anatomical features or otherwise facilitate the surgical procedure. Additionally, using the tracking system 222 of FIG 2 or some other approach to surgical navigation and tracking, the surgical system 200 can determine the relative orientation of the tracked bones.

[0031] The computing system 224 is configured to create a surgical plan and control the robotic device 220 according to the surgical plan to perform one or more bone modifications and / or facilitate the implantation of one or more prosthetic components. Accordingly, the computing system 224 is communicatively coupled to the tracking system 222 and the robotic device 220 to facilitate electronic communication between the robotic device 220, the tracking system 222, and the computing system 224. Additionally, the computing system 224 may be connected to a network and, for example, accessed by an electronic health record system, to receive information regarding the patient's medical history or other patient profile information, medical images, the surgical plan, the surgical procedure, and to perform various functions related to the operation of the surgical procedure. The computing system 224 includes a processing circuit 260 and an input / output device 262.

[0032] The input / output devices 262 are configured to receive user input and display output, as appropriate, for the functions and processes described herein. As shown in FIG. 2, the input / output devices 262 include a display 264 and a keyboard 266. The display 264 is configured to display a graphical user interface generated by the processing circuitry 260, including, for example, a surgical plan, medical images, information about settings and other options of the surgical system 200, status information related to the tracking system 222 and the robotic device 220, and tracking visualizations based on data provided by the tracking system 222. The keyboard 266 is configured to receive user input to those graphical user interfaces to control one or more functions of the surgical system 200.

[0033] The processing circuitry 260 includes a processor and a memory device. The processor can be implemented as a general-purpose processor, an application specific integrated circuit (ASIC), one or more field programmable gate arrays (FPGAs), a group of processing components, or other suitable electronic processing components. The memory device (e.g., memory, memory unit, storage device, etc.) is one or more devices (e.g., RAM, ROM, flash memory, hard disk storage, etc.) for storing data and / or computer code to complete or facilitate various processes and functions described herein. The memory device may be or include volatile or non-volatile memory. The memory device may include a database component, an object code component, a script component, or any other type of information structure to support various activities and information structures described herein. According to an exemplary embodiment, the memory device is communicatively coupled to the processor via the processing circuitry 260 and includes computer code for executing (e.g., by the processing circuitry 260 and / or the processor) one or more processes described herein.

[0034] More specifically, the processing circuitry 260 is configured to facilitate the creation of a pre-operative surgical plan prior to a surgical procedure. According to some embodiments, the pre-operative surgical plan is developed utilizing a three-dimensional representation of the patient's anatomy (also referred to herein as a "virtual bone model"). The "virtual bone model" may include virtual representations of cartilage or other tissues in addition to bone. To obtain the virtual bone model, the processing circuitry 260 receives imaging data of the patient's anatomy on which the surgical procedure is to be performed. The imaging data may be generated using any suitable medical imaging technique that images relevant anatomical features, including computed tomography (CT), magnetic resonance imaging (MRI), and / or ultrasound. The imaging data is then segmented (i.e., regions of the image corresponding to different anatomical features are differentiated) to obtain the virtual bone model. For example, For example, MRI-based scan data of a joint can be segmented to distinguish bone from surrounding ligaments, cartilage, previously implanted prosthetic components, and other tissues to obtain a three-dimensional model of the imaged bone.

[0035] Alternatively, the virtual bone model may be obtained by selecting a three-dimensional model from a database or library of bone models. In one embodiment, a user may use the input / output device 262 to select an appropriate model. In another embodiment, the processing circuitry 260 may execute stored instructions to select an appropriate model based on images or other information provided about the patient. The bone model(s) selected from the database may then be deformed based on specific patient characteristics to create the virtual bone model used in the surgical planning and implementation described herein.

[0036] A pre-operative surgical plan can then be created based on the virtual bone model. The surgical plan can be generated automatically by the processing circuitry 260, by user input using the input / output device 262, or some combination of the two (e.g., the processing circuitry 260 constrains some features of the user-created plan, generates a plan that the user can modify, etc.). In some embodiments, the surgical plan can be generated and / or modified based on distraction force measurements collected during surgery.

[0037] The pre-operative surgical plan includes the desired cuts, holes, surfaces, burrs, or other modifications to the patient's anatomy that are made using the surgical system 200. For example, for an entire knee arthroscopic procedure, the pre-operative plan may include the cuts necessary to form a distal surface, a posterior chamfer, a posterior surface, an anterior surface, and an anterior chamfer on the femur, in the proper relative orientation and relative position to mate with corresponding surfaces of a prosthesis that will be joined to the femur during the surgical procedure, as well as the cuts necessary to form a surface(s) on the tibia that are suitable to mate with a prosthesis that will be joined to the tibia during the surgical procedure. As another example, the pre-operative plan may include the modifications necessary to create a hole (e.g., pilot hole 120) in the bone. As another example, in a hip arthroplasty procedure, the surgical plan may include the necessary burrs to form one or more surfaces in the acetabular region of the pelvis to receive a cup (and, if appropriate, an implant augmentation). Thus, processing circuitry 260 may receive, access, and / or store a model of the prosthesis to facilitate generation of a surgical plan.

[0038] The processing circuit 260 is further configured to generate a control object for the robotic device 220 according to the surgical plan. The control object may take different forms according to different types of possible robotic devices (e.g., haptic devices, autonomous devices). For example, in some embodiments, the control object defines instructions for the robotic device to control the robotic device to move within the control object (i.e., instructions to autonomously make one or more cuts of the surgical plan guided by feedback from the tracking system 222). In some embodiments, the control object includes a visualization of the surgical plan and the robotic device on the display 264, which facilitates surgical navigation and helps guide the surgeon to follow the surgical plan (e.g., without active control or force feedback of the robotic device). In embodiments in which the robotic device 220 is a haptic device, the control object may be a haptic object, as described in the following paragraphs.

[0039] In embodiments in which the robotic device 220 is a haptic device, the processing circuitry 260 is further configured to generate one or more haptic objects based on the pre-operative surgical plan to assist the surgeon during implementation of the surgical plan by enabling constraint of the surgical tool 234 during the surgical procedure. The haptic objects may be formed in one, two, or three dimensions. For example, the haptic object may be a line, a plane, or a three-dimensional volume. The object may be curved and / or have flat surfaces and may be any shape (e.g., funnel-shaped). Haptic objects can be created to represent various desired results for moving the surgical tool 234 during a surgical procedure. One or more boundaries of a three-dimensional haptic object may represent one or more modifications, such as cuts, made on a surface of a bone. A planar haptic object may represent modifications, such as cuts, made on a surface of a bone. A curved haptic object may represent the resulting surface of the bone that is modified to receive a cup implant and / or an implant augment. A line haptic object may correspond to pilot holes made in the bone to prepare the bone to receive a screw or other protrusion.

[0040] In embodiments in which the robotic device 220 is a haptic device, the processing circuit 260 is further configured to generate a virtual tool representation of the surgical tool 234. The virtual tool represents a location of the physical surgical tool 234 and includes one or more haptic interaction points (HIPs) associated with the location. In embodiments in which the surgical tool 234 is a spherical bar (e.g., as shown in FIG. 2), the HIP may represent the center of the spherical bar. One HIP is used to virtually represent the surgical tool, and the HIP may be referred to herein as a tool center point (TCP). If the surgical tool 234 is an irregular shape, e.g., for a sagittal saw, the virtual representation of the sagittal saw may include many HIPs. The use of multiple HIPs to generate haptic forces (e.g., positive force feedback or resistance to movement) on a surgical tool is described in U.S. Application Serial No. 13 / 339,369, entitled "System and Method for Providing Substantially Stable Haptics," filed December 28, 2011, which is hereby incorporated by reference in its entirety. In one embodiment of the present invention, a virtual tool representing a sagittal saw includes eleven HIPs. As used herein, references to "HIPs" are deemed to also include references to "one or more HIPs." As described below, the relationship of HIPs to haptic objects allows the surgical system 200 to constrain the surgical tool 234.

[0041] Before the surgical procedure is performed, the patient's anatomy (e.g., femur 206) is registered to the virtual bone model of the patient's anatomy by any known registration technique. One possible registration technique is point-based registration as described in U.S. Patent No. 8,010,180, entitled "Haptic Guidance System and Method," issued on August 30, 2011, which is hereby incorporated by reference in its entirety. Alternatively, registration can be accomplished by 2D / 3D registration utilizing a handheld radiographic imaging device as described in U.S. Patent Application No. 13 / 562,163, entitled "Radiographic Imaging Device," filed on July 30, 2012, which is hereby incorporated by reference in its entirety. Registration also includes registration of the surgical tool 234 to a virtual tool representation of the surgical tool 234, which allows the surgical system 200 to determine and monitor the orientation of the surgical tool 234 relative to the patient (i.e., the femur 206). Registration allows for precise navigation, control, and / or force feedback during the surgical procedure. In some embodiments, additional details related to registration for a hip arthroplasty procedure are described in more detail below.

[0042] The processing circuitry 260 is configured to monitor the virtual tool representation, the virtual positions of the virtual bone models, and the control objects (e.g., virtual haptic objects) that correspond to real-world positions in one or more lines, planes, or three-dimensional space defined by the patient's bones (e.g., femur 206), the surgical tool 234, and the forces created by the robotic device 220. For example, as the patient's anatomy moves during the surgical procedure as tracked by the tracking system 222, the processing circuitry 260 moves the virtual bone models correspondingly. Thus, the virtual bone models correspond to the patient's actual (i.e., physical) anatomy and the real / physical space. The femur 206 corresponds to or is associated with the position and orientation of that anatomical structure during surgery. Similarly, any haptic object, control object, or other planned automated robotic device movements that occur during surgical planning related to cuts, modifications, etc. made to that anatomical structure also move in concert with the patient's anatomy. In some embodiments, the surgical system 200 includes clamps or braces that substantially immobilize the femur 206, minimizing the need to track and process the movements of the femur 206.

[0043] For embodiments in which the robotic device 220 is a haptic device, the surgical system 200 is configured to constrain the surgical tool 234 based on the relationship between the HIP and the haptic object. That is, when the processing circuit 260 uses the data provided by the tracking system 222 to detect that the user is manipulating the surgical tool 234 to move the HIP and virtually contact the haptic object, the processing circuit 260 generates control signals for the robotic arm 232 and provides haptic feedback (e.g., force, vibration) to the user to communicate a constraint on the movement of the surgical tool 234. Generally, the term "constraint" as used herein is used to describe a tendency to limit movement. However, the formation of the constraint imposed on the surgical tool 234 depends on the formation of the associated haptic object. The haptic object may be formed in any shape or configuration. As noted above, three exemplary embodiments include a line, a plane, or a three-dimensional volume. In one embodiment, the surgical tool 234 is constrained to limit the HIP of the surgical tool 234 from moving along the linear haptic object. In another embodiment, the haptic object is a three-dimensional volume and the surgical tool 234 can be constrained by substantially preventing movement of the HIP outside of the volume enclosed by the walls of the three-dimensional haptic object. In another embodiment, a planar haptic object constrains the surgical tool 234 to substantially prevent movement of the HIP outside of the plane and outside the boundaries of the planar haptic object. For example, the processing circuitry 260 can construct a planar haptic object corresponding to the planned planar distal cut that needs to be made on the distal surface of the femur 206 to substantially restrict the surgical tool 234 to the plane in which the planned distal cut needs to be performed.

[0044] For embodiments in which the robotic device 220 is an autonomous device, the surgical system 200 is configured to autonomously move and operate the surgical tool 234 according to a control object. For example, the control object may define an area relative to the femur 206 where the cut is to be made. In such a case, one or more motors, actuators, and / or other mechanisms of the robotic arm 232 and surgical tool 234 can be controlled to move and operate the surgical tool 234 as needed within the control object to make the planned cut, e.g., using tracking data from the tracking system 222 to enable closed-loop control.

[0045] Referring now to Figure 3, there is shown a flow chart of a process 300 that may be performed by the surgical system 200 of Figure 2, according to an exemplary embodiment. The process 300 may be adapted to facilitate a variety of surgical procedures, including total and partial joint replacement surgeries. The various steps and features shown in Figures 4-13 and described in detail below may be used to perform the process 300, including combinations of those steps and features.

[0046] In step 302, a surgical plan is obtained. The surgical plan (e.g., a computer readable data file) may define a desired outcome of bone modification, for example, based on the desired location of prosthetic components relative to the patient's anatomy. For example, for a knee arthroplasty procedure, the surgical plan may provide the planned locations and orientations of the planes 102-110 and pilot holes 120 shown in FIG. 1. The surgical plan may be generated based on medical images, three-dimensional modeling, surgeon input, etc.

[0047] In step 304, one or more control boundaries (e.g., haptic objects) are defined based on the surgical plan. The one or more haptic objects may be one-dimensional (e.g., line haptics), two-dimensional (i.e., planar), or three-dimensional (e.g., cylindrical, funnel-shaped, curved, etc.). The haptic objects may represent planned bone modifications (e.g., haptic objects for each of the planes 102-110 and for each of the pilot holes 120 shown in FIG. 1), implant components defined by the surgical plan, surgical approach trajectories, etc. The haptic objects can be oriented and positioned in three-dimensional space relative to tracked locations of the patient's anatomy.

[0048] In step 306, the pose of the surgical tool is tracked relative to the haptic object(s), for example by tracking system 222 described above. In some embodiments, one point on the surgical tool is tracked. In other embodiments, two points on the surgical tool are tracked (e.g., in the example of Figures 4-5), for example, a tool center point (TCP) at the tip / active end of the surgical tool and a second interaction point (SIP) located along the body or handle of the surgical tool. In other embodiments, three or more points on the surgical tool are tracked. The pose of the surgical tool is known relative to a coordinate system that defines one or more haptic objects, and in some embodiments, the pose of one or more anatomical features of the patient is also tracked.

[0049] At step 308, the surgical tool is guided to the haptic object(s). For example, the display 264 of the surgical system 200 may display a graphical user interface that moves the surgical tool and / or the robotic device and instructs the user how (e.g., in what direction) to move the surgical tool to the haptic object. As another example, the surgical tool may be guided to the haptic object using collapsing haptic boundaries as described in U.S. Patent No. 9,289,264, the disclosure of which is incorporated herein by reference. As another example, a robotic device may be controlled to automatically move a surgical tool to a haptic object. As another example, step 308 may be performed using process 800 of FIG. 8, which is described in detail below.

[0050] In step 310, the robotic device is controlled to constrain the movement of the surgical tool based on the tracked pose of the surgical tool and the pose of the one or more haptic objects. Constraining the surgical tool may be accomplished as described above with reference to FIG. 2. In some embodiments, step 310 includes a two-stage approach as shown in FIGS. 4-5 and described below with reference to those figures. In some embodiments, step 310 includes providing a damping force that resists movement of the surgical tool through a particular zone, for example as shown in FIGS. 9-10 and described below with reference to those figures. In some embodiments, step 310 includes adjusting the haptic interaction in response to a user input, for example according to the example of FIGS. 11-13 and described below with reference to those figures. Various combinations of these features are possible in step 310.

[0051] In step 312, removal of the surgical tool from the haptic object(s) is facilitated, i.e., release of the constraint of the haptic object is facilitated. For example, in some embodiments, the robotic device is controlled to allow the surgical tool to exit the haptic object along the axis of the haptic object. In some embodiments, the surgical tool may allow the haptic object to exit in a predefined direction relative to the haptic object, as shown, for example, in FIGS. 6-7 and described in detail below with reference thereto. Thus, the surgical tool may be removed from the surgical field and the haptic object, facilitating subsequent steps of the surgical procedure. It should further be understood that, in some cases, the process 300 may return to step 308 to guide the surgical tool to the same or a different haptic object after exiting the haptic object in step 312.

[0052] Thus, the process 300 may be performed by the surgical system 200 to facilitate a surgical procedure. According to some embodiments, features of the process 300 are illustrated in Figures 4-13 below, and such features may be combined in various combinations in various embodiments and / or based on the settings selected for a particular procedure. Additionally, it should be understood that the features of Figures 4-13 may be provided while omitting some or all other steps of the process 300. All such possibilities are within the scope of the present disclosure.

[0053] 4-5, a two-stage haptic interaction is illustrated in accordance with an exemplary embodiment. Figure 4 illustrates a flow chart of a process 400 for providing a two-stage haptic interaction, while Figure 5 illustrates a storyboard illustration of the two-stage haptic interaction (i.e., the haptic interaction of process 400). Process 400 may be performed by surgical system 200, for example, at step 310 of process 300.

[0054] In step 402, a tool center point (TCP) 500 is constrained to a line haptic 502 while allowing rotation of the surgical tool 234 about the tool center point 500 and translation of the TCP 500 along the line haptic 502. The line haptic 502 may correspond to a planned bone modification (e.g., planned pilot hole 120) as shown in FIG. 1. The line haptic 502 may be defined as the axis of the planned pilot hole 120 and may extend from the bottom (innermost end) of the planned pilot hole 120 and extend beyond the anatomical feature (e.g., femur 101). The line haptic 502 is a straight line in the example of FIG. 5. In other embodiments, the line haptic 502 may be curved, e.g., defined as a spline. In other embodiments, the process 400 of FIG. 4 may be adapted to use a planar haptic object, a volumetric haptic object, or a haptic object defined as any combination of a line, a plane, and / or a volume in place of the line haptic 502.

[0055] The TCP 500 is tracked relative to the line haptics 502, and the robotic device is controlled to constrain the TCP 500 to stay or substantially stay on the line haptics 502 (e.g., prevent or resist slippage from the line haptics 502, provide a spring force to drive the TCP 500 back to the line haptics 502, etc.). In step 402, the TCP 500 can translate along the line haptics 502. The robotic device is controlled (e.g., by admittance control) to allow the surgical tool 234 to rotate about the TCP 500 (e.g., as manipulated by a user). That is, in step 402, a second interaction point (SIP) 504 located along the handle or body of the surgical tool 234 releases the constraint.

[0056] Rotation of the surgical tool 234 about the TCP 500 in step 402 may facilitate the surgeon reaching the line haptics 502 along the preferred approach trajectory. In some cases, surrounding soft tissue and / or bone structures may make it difficult or impossible to insert the surgical tool 234 along the line haptics 502 from a position sufficiently outside the patient relative to the bone surface without causing undesired or unnecessary disruption of the surrounding tissue or bone (e.g., without having to create a hole through such tissue or bone). In such cases, the surgical tool 234 may be inserted along the preferred trajectory until the TCP 500 reaches and is constrained by the line haptics 502. In step 402, the surgical tool 234 may be rotated to displace an anatomical feature by pushing such feature with the side of the shaft or body of the surgical tool. By constraining the TCP 500 to the line haptics 502 in step 402, the surgeon is able to concentrate on rotating the surgical tool 234 as desired, without the burden of also monitoring the position of the TCP 500 and / or manually attempting to prevent movement of the TCP 500 away from the desired axis. Thus, , step 402 may facilitate the insertion and orientation of the surgical tool 234 within various anatomical regions.

[0057] In step 404, it is determined (e.g., by the processing circuitry 260) that the TCP 500 has reached a threshold position along the line haptic 502. In some cases, the threshold position is defined based on a distance away from a surface of the bone (e.g., the femur 101) such that the threshold position is reached before the surgical tool 234 contacts the bone. In such a case, as described below, steps 406-408 may be performed before the surgical tool 234 begins modifying the bone, thus ensuring a desired orientation of the surgical tool 234 before initiating bone modification.

[0058] In other cases, the threshold position is defined based on a depth below the bone surface whereby the threshold position is reached after the surgical tool 234 contacts the bone. In such cases, the surgical tool 234 may be allowed to begin bone modification in a first orientation before rotating in alignment with the line haptics 502, as described below with reference to steps 406-408, which may, for example, reduce the risk of skiving or otherwise facilitate the penetration of the surgical tool 234 into the bone. As shown in FIG. 5, for example, initial contact may be made between the surgical tool 234 and the bone 101, with the surgical tool approximately perpendicular to the bone surface as shown in the upper frame (i.e., during step 402), which may improve the likelihood of achieving a clean cut / hole / slot, etc. in the bone 101 at the planned location (i.e., the intersection of the line haptics 502 and the bone 101). In such a case, after the initial penetration of the surgical tool 234 into the bone 101 (i.e., once the TCP 500 has crossed the surface of the bone 101), a determination may be made that the TCP 500 has reached a threshold position.

[0059] In step 406, in response to determining that the TCP 500 has reached the threshold position in step 404, the SIP 504 is guided toward the line haptics 502. In some embodiments, the robotic device may be controlled to provide an assisting force to assist the user in rotating the surgical tool 234 about the TCP 500 and moving the SIP 504 toward the line haptics 502. In some embodiments, a collapsing haptic object is used in step 406 to prevent rotation of the SIP 504 away from the line haptics 502 while allowing rotation of the SIP 504 toward the line haptics 502. In some embodiments, the display 264 provides instructions to guide the SIP 504 toward the line haptics 502. In some embodiments, the robotic device is controlled to automatically rotate the surgical tool 234 and align the SIP 504 with the line haptics 502 to provide guidance of the SIP 504 toward the line haptics 502. The TCP 500 is constrained to the line haptics 502 (described for step 402) during step 406 (i.e., while the SIP 504 guides the line haptics 502). Optionally, the robotic device is controlled to prevent translation of the TCP 500 along the line haptics 502 while the SIP 504 is guided during step 406.

[0060] In step 408, after the SIP 504 is guided to the line haptics 502 as a result of step 406, the robotic device is controlled to constrain the TCP 500 and the SIP 504 to the line haptics 502. The surgical tool 234 can translate along the line haptics 502 to perform the planned bone modification (e.g., create the pilot hole 120). In the example shown, the SIP 504 is located along the axis of the surgical tool 234. Thus, by constraining the other surgical tool 234 to the line haptics 502 at two points (i.e., the TCP 500 and the SIP 504), the alignment of the surgical tool 234 with the line haptics 502 is maintained. In other embodiments, the SIP 504 is guided to a second haptic (i.e., a virtual haptic object different from the line haptics 502). In such an embodiment, the TCP 500 and the SIP 504 are constrained to different haptic objects. For example, if the surgical tool 234 is bent, the surgical tool 234 may be moved to the line haptics 502. To achieve the desired release and restriction of movement of the tool 234, the SIP 504 may be constrained to a curve while the TCP 500 is constrained to a straight line (or vice versa).

[0061] Also, other geometries and behaviors may be possible by using different haptic objects for the SIP 504 and the TCP 500. For example, the TCP 500 may be restricted to a haptic object that corresponds to the geometry of a planned cut or drilling path, while the SIP 504 is restricted to a different haptic object that is configured to prevent or resist collision of the shaft of the surgical tool 234 (or other point of the robotic arm) with one or more objects in the surgical field. For example, the SIP 504 may be restricted to a haptic object having a geometry based on the position of a retractor or other tool in the surgical field (e.g., the tracked position of the retractor). As another example, the SIP 504 may be restricted to a haptic object having a geometry based on the position of an anatomical feature. For example, the anatomical feature may correspond to the shape of a surgical port or other incision or opening through which the shaft of the surgical tool 234 extends during the performance of the planned bone preparation. Thus, the control of the robotic device can be configured to constrain the TCP 502 to a first haptic object and constrain the SIP 504 to a second haptic object to guide the TCP 502 according to the planned bone preparation while avoiding undesired behavior of the tool shaft by constraining the SIP 504. Thus, the process 400 can be executed by the surgical system 200 to provide precise bone modifications in a reliable and easy to use manner.

[0062] 6-7, a process 600 for facilitating removal of a surgical tool from a haptic object is shown, in accordance with an exemplary embodiment. FIG. 6 shows a flow chart of process 600, while FIG. 7 shows a haptic object that may be used in conjunction with process 600 of FIG. 6. Process 600 may be performed by surgical system 200, for example, at step 312 of process 300. In the example of FIGS. 6-7, a cylindrical haptic object is contemplated, however, it should be understood that process 600 may be adapted to control objects having a variety of geometric shapes.

[0063] In step 602, the robotic device is controlled to constrain the surgical tool 234 to the cylindrical haptic object. FIG. 7 shows an example of a cylindrical haptic object 700 centered on a target axis 702. In some embodiments, the cylindrical haptic object 700 corresponds to a surgical approach trajectory and / or a planned bone modification (e.g., a planned pilot hole 120). The cylindrical haptic object 700 may extend substantially beyond (away from) a sensitive anatomical region. When the surgical tool 234 is constrained to the cylindrical haptic object 700, the surgical tool 234 may partially obstruct access to the surgical field. It may therefore be desirable for the surgeon to move the surgical tool out of the cylindrical haptic object 700 in a safe direction to facilitate various steps of the surgical procedure.

[0064] At step 604, a force 234 of the surgical tool against a boundary of the cylindrical haptic object is detected. Forces (e.g., twists at joints of the robotic arm 232) can be detected by the robotic device 220. For example, a HIP associated with the surgical tool 234 can be positioned at the boundary of the cylindrical haptic object 700 while a user exerts a force on the surgical tool 234, pushing the surgical tool 234 against or into the boundary.

[0065] In step 606, it is determined (e.g., by processing circuitry 260) whether the force detected in step 604 is directed in a predefined ejection direction. The predefined ejection direction may be chosen as a safe and / or convenient direction that may allow surgical tool 234 to exit the haptic object. For example, the predefined exit direction may be defined by an exit region 704 of cylindrical haptic object 700 and a wall 706 extending from cylindrical haptic object 700 at exit region 704. In such an example, the force detected in step 604 may be directed in a predefined ejection direction. If the HIP of the surgical tool 234 is in the exit region 704 when applied against the boundary of the haptic object 700, the processing circuitry 260 can determine that the force is directed in a predefined exit direction. In some embodiments, as shown in FIG. 7, the exit 704 spans only a portion of the length of the haptic object 700, e.g., is blocked by a dead zone 708. As another example, in some embodiments, the processing circuitry 260 can determine a directional vector that points in the direction in which the user is pushing the tool out. In such a case, it can determine whether the directional vector is within a threshold angle of the predefined exit direction. In this example, if the directional vector falls within a threshold angle of the predefined exit direction, the force is deemed to be directed in the predefined exit direction (i.e., proceed to "Yes" at step 606). Thus, the resulting exit boundary can take the shape of a funnel.

[0066] If the force is not directed in the predefined exit direction, the process 600 returns to step 602 and the surgical tool 234 is constrained to the cylindrical haptic object 700. That is, the robotic device 220 is controlled to provide force feedback to constrain the surgical tool from exiting the cylindrical haptic object 700, for example, to facilitate one or more steps of a surgical procedure.

[0067] If the force is directed in a predefined exit direction (as determined in step 606), then in step 608 a determination is made (e.g., by processing circuit 260) as to whether the force is greater than a threshold amount of force. In some embodiments, the amount of force exerted on surgical tool 234 may be measured by a joint of robotic arm 232. While a user may indicate a desire to eject a haptic object by exceeding a threshold amount of force, the threshold amount of force may be set high enough to substantially prevent accidental or unintentional ejection from a haptic object.

[0068] If the force is less than the threshold amount of force, the robotic device 220 is controlled to constrain the surgical tool 234 from exiting the haptic object (e.g., constraining it from passing through the exit region 704 of the cylindrical haptic object 700). The process 600 returns to step 602, where the surgical tool 234 remains constrained to the cylindrical haptic object 700, facilitating use of the surgical tool 234 to perform a step of the surgical procedure.

[0069] If in step 608 it is determined that the force exceeds the threshold amount of force, then in step 610 the surgical tool projects the haptic object in a predefined exit direction. In the example of FIG. 7 , releasing the constraint associated with the exit region 704 allows the surgical tool 234 to move through the exit region 704 and exit the cylindrical haptic object 700. The wall 706 may be included as a haptic boundary to guide the surgical tool 234 away from the axis 702 in a predefined direction. In other words, the surgical tool 234 may be pushed across the entirety of the exit region 704 of the cylindrical haptic object 700, projecting the cylindrical haptic object in a predefined direction.

[0070] Thus, allowing the surgical tool 234 to exit the haptic object does not control the robotic device to constrain the surgical tool 234 to the haptic object. Optionally, the surgical tool 234 can be reinserted into the haptic object (i.e., resume haptic constraint) via the exit region 704 and / or using any other haptic initiation procedure (e.g., a procedure following the process of FIG. 8). Optionally, the haptic object is removed (deleted, etc.) when the surgical tool 234 exits the haptic object. Optionally, the haptic object is adjusted or a new haptic object is activated to facilitate a subsequent step of the surgical procedure. Thus, the process 600 may be performed one or more times by a surgical procedure to facilitate a surgical procedure.

[0071] With reference now to FIG. 8, in accordance with an illustrative embodiment, a surgical tool may be associated with a virtual control object. 8, a flow chart is shown illustrating a process 800 for guiding to a target (e.g., a haptic object). Process 800 can be performed by surgical system 200, for example, at step 308 of process 300.

[0072] In step 802, a virtual control object is constructed. That is, a virtual control object is generated and a pose of the virtual control object is defined. The virtual control object may include one or more of a point object, a line object, a planar object, or a three-dimensional surface or volume, as described in detail above with reference to FIG. 2. In some cases, the virtual control object is a haptic object. Process 800 may be adapted for use with a variety of virtual control objects having a variety of shapes.

[0073] At step 804, the movement of the surgical tool 234 is tracked (e.g., by the tracking system 222). For example, a point associated with the surgical tool 234 (e.g., a tool center point) can be determined and updated over time. The position of the point can be defined relative to a virtual control object (i.e., in a coordinate system in which the pose of the virtual control object is also defined). The surgical tool 234 can be moved by manipulation by a user.

[0074] In step 806, the direction of movement of the surgical tool is determined (e.g., by the processing circuitry 260). For example, the positions of points associated with the surgical tool 234 can be repeatedly collected to obtain a time series of position data over time. Given two positions (e.g., positions for subsequent time steps), a vector (e.g., a velocity vector) can be defined that characterizes the direction of movement of the surgical tool 234. In some cases, the velocity of movement (e.g., the magnitude of the velocity vector) is determined based on the distance between the positions used and the elapsed time between those collected data points. In some cases, if the magnitude of the velocity vector exceeds a threshold, the process 800 does not proceed to step 808.

[0075] In step 808, a determination is made (e.g., by the processing circuit 260) as to whether the movement direction is toward the virtual control object. For example, the velocity vector determined in step 806 may extend (e.g., to infinity) from the most recent tracked position of the surgical tool in the movement direction. For example, if the extending velocity vector intersects the virtual control object, it may be determined that the movement direction is toward the virtual control object. If the extending velocity vector does not intersect the virtual control object, it may be determined that the movement direction is not toward the virtual control object. In various embodiments, various other statistical methods, coordinate transformations, etc. may be used to determine whether the movement direction of the surgical tool is toward the virtual control object. For example, in some embodiments, a target volume is defined in the virtual control object (e.g., defined around, adjacent to, extending from the object), and if the extending velocity vector intersects the target volume, it may be determined that the movement direction is toward the virtual control object. If the virtual control object is a line, the target volume may be defined, for example, as a cylinder with the line at its center.

[0076] If the direction of movement is not towards the virtual control object, the process 800 returns to step 804 to track the movement of the surgical tool 234. Steps 804-808 may be repeated until the direction of movement is towards the virtual control object.

[0077] If it is determined that the direction of movement is toward the virtual control object, then in step 810, the robotic device 220 is controlled to provide a force to guide the surgical tool 234 toward the virtual control object. For example, a positive assist force may be provided that assists the user in moving the surgical tool 234 toward the virtual control object. The positive assist force may be insufficient to independently move the surgical tool 234 without an external force supplied by the user. In some cases, the force applied in step 810 may be sufficient to guide the surgical tool 234 toward the virtual control object. As another example, in some embodiments, forces are provided as haptic boundaries (e.g., collapsing haptic boundaries) to constrain the surgical tool 234 from moving away from and / or reoriented toward the virtual control object.

[0078] Thus, the surgical system 200 may execute the process 800 to facilitate a user moving a surgical tool to a virtual control object in response to the user initiating movement of the surgical tool toward the virtual control object. For example, various movements of the surgical tool away from the virtual control object may be desired to properly position the surgical tool 234, the robotic arm 232, anatomical structures, other surgical equipment, etc., before use of the virtual control object is desired. The process 800 provides an efficient workflow that is user-friendly and easy for a user to utilize, allowing the surgical tool to move freely until it is moved toward the virtual control object (e.g., toward the surgical field where the virtual control object is located), at which point the system 200 automatically begins guidance of the surgical tool to the virtual control object.

[0079] 9-10, a process for providing a haptic interaction including attenuation zones is illustrated in accordance with an exemplary embodiment. FIG. 9 illustrates a process 900 for providing a haptic interaction including attenuation zones, while FIG. 10 illustrates an exemplary haptic object including attenuation zones. Process 900 may be performed by surgical system 200, for example, at step 310 of process 300. Although a cylindrical haptic object is shown in FIG. 10 for illustrative purposes, it should be understood that the features of FIGS. 9-10 may be adapted for use with virtual control objects of various geometric shapes.

[0080] In step 902, a haptic object having an attenuation zone is constructed (e.g., defined in virtual space by processing circuitry 260). The attenuation zone may be defined as a sub-portion of the haptic object and / or as a region within the haptic object. An exemplary haptic object 1000 having an attenuation zone 1002 is shown in FIG. 10. As shown in FIG. 10, the haptic object 1000 is a cylindrical haptic object and the attenuation zone 1002 is a cylindrical disk positioned in the haptic object 1000. In the example of FIG. 10, the haptic object 1000 and the attenuation zone 1002 have equal diameters, while the height of the attenuation zone 1002 is significantly less than the height of the haptic object 1000 and is centered about a shared axis 1004. In other embodiments, various relative sizes and dimensions are possible.

[0081] In some examples, the attenuation zone 1002 is positioned along the haptic object 1000 proximate to a surface of an anatomical feature (e.g., a bone). For example, the attenuation zone 1002 may be outside the surface of the bone. In such a case, as the tracked surgical tool 234 approaches the bone while being constrained by the haptic object 1000, the surgical tool 234 reaches the attenuation zone 1002 first.

[0082] At step 904, it is determined (e.g., by the processing circuit 260 using data from the tracking system 222) that the surgical tool 234 is in a first side of the attenuation zone 1002. In the example of Figure 10, the position of the TCP of the surgical tool 234 may be tracked relative to the attenuation zone 1002, and the surgical tool 234 may be determined to be in the first side of the attenuation zone 1002 when the TCP intersects the first surface 1006 of the attenuation zone 1002.

[0083] In step 906, the robotic device 220 is controlled to provide haptic feedback that partially resists movement of the surgical tool through the attenuation zone. Control of the robotic device 220 based on the motion may slow the movement of the surgical tool 234 (e.g., slow to not exceed a preset speed) as the surgical tool 234 passes through the attenuation zone. If the attenuation zone is positioned at the surface of the bone, then the attenuation zone may operate to manage (e.g., slow) the translational speed of the surgical tool 234 at the initial impact between the surgical tool 234 and the bone. Thus, by slowing down the translational speed of the surgical tool 234, the attenuation zone provided by the process 900 reduces skiving, increases the quality of the cut holes or holes / drilling, and improves the accuracy of the cut or hole placement.

[0084] 9-10 show damping zones where the movement of the robotic device 220 is damped, as described above, but in other embodiments, other types of zones associated with other effects are provided, in which case step 906 is adapted accordingly. For example, in some embodiments, the damping zones are replaced with acceleration zones, and in step 906, the robotic device 220 increases the speed of the surgical tool 234 as the surgical tool passes through the acceleration zone. As another example, in some embodiments, the damping zones are replaced with attraction zones (controlling the robotic device 220 to provide a force to the surgical tool 234 that is directed toward the location of the attraction zone (e.g., the midpoint of the attraction zone)) or repulsion zones (controlling the robotic device 220 to provide a force to the surgical tool 234 that is directed away from the location of the repulsion zone).

[0085] In step 908, it is determined (e.g., by the processing circuit 260 using data from the tracking system 222) that the surgical tool has exited the second side of the attenuation zone. In the example of Figure 10, the position of the TCP of the surgical tool 234 may be tracked relative to the attenuation zone 1002, and the surgical tool 234 may be determined to have exited the second side of the attenuation zone 1002 when the TCP passes the second side 1008 of the attenuation zone 1002.

[0086] In step 910, in response to determining that the surgical tool has exited the second side of the attenuation zone, the attenuation zone is removed (e.g., by the processing circuitry 260) from the haptic object. The resistance feedback applied in step 906 is not applied. In some embodiments, the surgical tool can repeatedly pass through the area previously occupied by the attenuation zone without encountering the resistance of step 906. Thus, the surgical system 200 can be configured to provide attenuation resistance to facilitate initial contact between the surgical tool 234 and the bone and to automatically remove such resistance after initial contact.

[0087] 11-13, a flow chart is shown illustrating a process for adjusting haptic interactions in response to input received from a user via a button (key, trigger, switch, pressure sensor, hand position sensor, etc.) mounted on a surgical tool or robotic arm, according to an exemplary embodiment. With reference to FIG. 2, the process of FIGS. 11-13 contemplates that the button is located on a grip or handle area of ​​the robotic arm 232 or surgical tool 234, such that the button is readily available to a user (e.g., a surgeon) while the user manipulates the robotic arm 232 and surgical tool 234 during the performance of a surgical procedure. The button may be selected by the user without the user having to change the user's grip on the robotic arm 232 and / or surgical tool 234, and without the user having to change the user's view or attention away from the surgical field. The process of FIGS. 11-13 may be performed by the surgical system 200, for example, as part of step 310 of FIG. 3.

[0088] FIG. 11 shows a flow chart of a process 1100 in which a button allows a user to switch between a first haptic object and a second haptic object. In step 1102, the surgical tool 234 is The first haptic object may have any of the dimensions, shapes, etc. described herein. In step 1104, an electrical signal is received (e.g., at processing circuit 260) indicating the pushing of a button mounted on the surgical tool or robotic arm. In step 1106, haptic control of the surgical tool 234 is switched from the first haptic object to a second haptic object such that, in step 1108, the surgical tool 234 is constrained to the second haptic object. Optionally, a button can be pushed to again return control based on the first haptic object.

[0089] Process 1100 may provide various advantages based on the relative size, shape, etc. of the first and second haptic objects. In some embodiments, the first haptic object is a sub-part of the second haptic object (i.e., the second haptic object is capable of a wider range of motion than the first haptic object). In such a case, the user may select a button to allow the surgical tool 234 to be controlled based on the first haptic object to reach areas that the surgical tool is constrained not to reach. One example is a set of planar haptic objects, where the first haptic object corresponds to a virtually determined extent of a planar cut, while the second haptic object is a large coplanar object. Based on the surgeon's experience and observations during surgery, the surgeon can push a button to extend the cut during surgery, if necessary. As another example, the first haptic object and the second haptic object may only partially overlap. In such an example, process 1100 may facilitate switching between different steps of a surgical procedure. In some embodiments, processing circuitry 260 prevents switching of the haptic control object unless the surgical tool is currently located within both of the haptic objects.

[0090] 12 illustrates a process 1200 in which a button allows a user to extend a haptic object in the direction of a force applied by the user. In step 1202, a surgical tool is constrained to a first haptic object. The first haptic object may have any of the dimensions, shapes, etc. described herein. In step 1204, an electrical signal is received (e.g., at processing circuit 260), the electrical signal indicating a push of a button mounted on the surgical tool or robotic arm.

[0091] In step 1206, in response to the signal from the button, the direction of the force on the surgical tool is determined (e.g., by processing circuit 260). The HIP of the surgical tool may be positioned at the boundary of the first haptic object, such that the haptic control interaction prevents the force from moving the surgical tool further in the direction of the force. In such a scenario, the push of the button indicates that the user desires to move the surgical tool further in the direction of the force. Thus, in step 1208, the first haptic object extends in the direction of the force, thus allowing the surgical tool to move further in that direction before being constrained by the first haptic object. The first haptic object may extend by a preset distance or volume in step 1208. The surgical tool is then constrained by the extended first haptic object.

[0092] Thus, process 1200 may facilitate a user extending a surgical tool beyond the first haptic object in a particular direction selected by the user. For example, in some cases, control based on the first haptic object may constrain the surgical tool from reaching the full extent of an anatomical feature that the surgeon wishes to modify with the surgical tool. The surgeon may then push the surgical tool toward the target feature and select a button to extend the haptic object toward the target feature. Thus, process 1200 facilitates convenient intraoperative adjustments to the haptic object.

[0093] FIG. 13 shows a flow chart of process 1300, where buttons allow a user to adjust a virtual dimension of a virtual tool, thereby adjusting a virtual control interaction. In an embodiment contemplated by process 1300, the haptic control interaction is achieved by tracking a haptic interaction point (e.g., a HIP) associated with a surgical tool. The HIP is a one-dimensional point. The processing circuitry determines a volume occupied by the surgical tool using one or more virtual dimensions of the surgical tool based on the location of the HIP. For example, for a spherical bar, the HIP may be located at the center of the spherical bar, and the radius of the bar may be used to determine a three-dimensional volume occupied by the spherical bar in virtual space based on the HIP location and the radial dimension. Haptic control is provided based on the interaction of the volume occupied by the surgical tool (or the boundary of the surgical tool) with the haptic object. In the example of a spherical bar, the HIP may be constrained to a position offset from the haptic boundary by at least the radial dimension of the spherical bar. In such a case, changing the virtual radius of the spherical bar may allow the HIP to move closer to the haptic boundary. Thus, by modifying the virtual dimensions of the surgical tool, the control of the robotic device can be altered.

[0094] In step 1302, the surgical tool is constrained to a first haptic object. The first haptic object may have any of the dimensions, shapes, etc. described herein. In step 1304, an electrical signal is received (e.g., by processing circuitry 260), the electrical signal indicative of a push of a button mounted on the surgical tool or the robotic arm. In step 1306, in response to the signal from the button, a virtual dimension of the surgical tool is adjusted (e.g., by processing circuitry 260). For example, in a scenario where the surgical tool is a spherical bar, the virtual radius of the spherical bar may be decreased.

[0095] In step 1308, the robotic device is used to constrain the surgical tool to the first haptic object based on the adjusted virtual dimensions of the surgical tool. In instances where the virtual dimensions of the surgical tool are reduced (e.g., the radius is reduced), the surgical tool may be given a wider range of motion in step 1308 compared to step 1302. In such a case, the surgeon may turn on a button when he or she wishes to allow the surgical tool to reach a position that the surgical tool was constrained not to reach in step 1302. The location of the virtual center point of the surgical tool may also be shifted (e.g., in step 1306) relative to the tracked position of the surgical tool, such that, for example, the reduced size virtual tool is aligned with the boundaries of the original size virtual tool. This shift may give the surgical tool a wider range of motion in several directions while preserving the range of motion along the boundaries. For example, as the virtual dimensions of the surgical tool decrease, a shift in the virtual center point toward the distal end of the surgical tool may allow for an increased lateral range of motion (i.e., an increased range of motion perpendicular to the axis of the surgical tool) while limiting the surgical tool to the original cut depth. Thus, process 1300 may facilitate intraoperative fine-tuning of the range of anatomical features that can be modified by the surgical tool according to the surgical plan.

[0096] In some embodiments, repeated selection of the button may result in repeated adjustments to one or more virtual dimensions of the surgical tool (e.g., stepping to smaller and smaller sizes, switching between two available sizes, transitioning continuously through three or more available sizes, etc.) Many such possibilities are within the scope of this disclosure.

[0097] In other embodiments, the input is received from another source (e.g., foot pedal, voice activation, mouse, keyboard, touch screen, etc.) In other embodiments, the user input (such as the button-generated user input illustrated in FIGS. 11-13) is replaced with an automated response based on the tracked position or behavior of the surgical tool and / or robotic device. For example, some embodiments detect the dwell time of a surgical tool at a boundary of a haptic object, and when the dwell time exceeds a threshold time, the haptic control may be modified as described in steps 1106-1108, steps 1206-1210, and / or steps 1306-1308. Various such modifications are within the scope of this disclosure.

[0098] As noted above, all combinations of the various features shown in Figures 4-13 are within the scope of the present disclosure. For example, process 300 can be implemented using one or more steps of process 400, process 600, process 800, process 900, process 1100, process 1200, and process 1300. Additionally, it should be understood that the various features, method steps, etc. described herein may be adapted for use in facilitating a variety of surgical procedures, including total and partial hip, knee, and shoulder arthroplasty surgery, as well as for use in performing non-surgical tasks.

[0099] The configurations and arrangements of the systems and methods shown in the various exemplary embodiments are illustrative only. Although only a few embodiments have been described in detail in this disclosure, many modifications are possible (e.g., the size, dimensions, structure, shape and proportions of the various elements, the values ​​of parameters, the use of materials, colors, orientations, etc. can be changed). For example, the positions of the elements can be reversed or otherwise changed, and the nature or number of individual elements or positions can be changed or altered. Accordingly, all such modifications are intended to be included within the scope of this disclosure. The order or sequence of any process or method steps can be changed or re-sequenced according to alternative embodiments. The systems described herein can be adapted to carry out the methods described herein. Other substitutions, modifications, changes, and omissions can be made to the design, operating conditions, and arrangements of the exemplary embodiments without departing from the scope of this disclosure.

[0100] As used herein, the terms "approximately," "about," "substantially," and similar terms are intended to have broad meanings consistent with common usage and commonly accepted usage by those of ordinary skill in the art to which the subject matter of the present disclosure pertains. It should be understood by those of ordinary skill in the art reviewing the present disclosure that these terms are intended to enable the description of the specific features described and claimed without limiting the scope of these features to the precise numerical ranges provided. Thus, these terms should be interpreted as indicating minor or insignificant modifications or alterations of the subject matter described, which are considered to be within the scope of the present disclosure.

Claims

1. Defining a virtual object; defining a first point and a second point associated with a virtual representation of a surgical tool, wherein movement of the virtual representation of the surgical tool corresponds to movement of the surgical tool in real space; controlling a robotic device coupled to the surgical tool to constrain the first point to the virtual object; determining that the first point is at a threshold position along the virtual object; controlling the robotic device to guide the second point toward the virtual object; The method includes:

2. 2. The method of claim 1, wherein controlling the robotic device to constrain the first point to the virtual object comprises controlling the robotic device to prevent movement of the first point away from the virtual object and allow rotation of the surgical tool about the first point.

3. determining that the second point is located on the virtual object; constraining the first point and the second point to the virtual object; The method of claim 1 further comprising:

4. detecting a force on the tool in a predetermined direction, the predetermined direction being perpendicular to the virtual object; determining whether the force in the predetermined direction exceeds a threshold force; in response to determining that the force in the predetermined direction exceeds a threshold force, controlling the robotic device to allow the first point and the second point to deviate from the virtual object; The method of claim 3 further comprising:

5. Defining an attenuation zone along the virtual object; determining that the first point is within the attenuation zone; controlling the robotic device to resist movement of the first point through the attenuation zone; The method of claim 1 further comprising:

6. determining that the first point passes through the attenuation zone; removing the attenuation zone from the virtual object in response to determining that the first point passes through the attenuation zone; The method of claim 5 , comprising:

7. 2. The method of claim 1, wherein controlling the robotic device to guide the second point to the virtual object comprises controlling the robotic device to provide an assistive force to the surgical tool, the assistive force directed to facilitate movement of the second point to the virtual object.

8. determining that the first point is moving towards the virtual object; and controlling the robotic device to provide an assistive force to the surgical tool in response to determining that the first point is moving toward the virtual object, the assistive force being directed to facilitate movement of the first point toward the virtual line. The controlling. The method of claim 1 , comprising:

9. Receiving a signal; and Varying a control interaction between the first point and the virtual object in response to the signal; and The method of claim 1 , comprising:

10. Defining the virtual object includes: obtaining a surgical plan including a planned hole in a target bone; aligning the virtual object with the planned hole; The method of claim 1 , comprising:

11. The method of claim 1 , wherein the threshold position along the virtual object corresponds to a threshold distance from an anatomical feature.

12. The method of claim 1 , wherein the threshold position along the virtual object corresponds to an amount of penetration into an anatomical feature.

13. The method of claim 1 , wherein the virtual object is a virtual line.

14. 1. A method of operating a robotic device to which a tool is coupled, comprising the steps of: controlling the robotic device to constrain the surgical tool based on a first haptic object; receiving a signal and a user defined direction; adjusting a haptic control interaction in response to the signal by extending the first haptic object in a direction defined by the user; The method comprising:

15. The method of claim 14 , wherein receiving the user-defined direction comprises determining a direction of a force exerted by a user on the tool.

16. Adjusting the haptic control interaction in response to the signal includes: adjusting a virtual dimension of the tool; constraining the surgical tool to the first haptic object based on the adjusted virtual dimensions of the tool; 15. The method of claim 14, comprising:

17. the first haptic object includes a line haptic; The method of claim 14 , wherein constraining the tool to the first haptic object includes constraining a first point associated with the surgical tool to the line haptic.

18. Detecting a force on the tool in a predetermined direction; determining whether the force in the predetermined direction exceeds a threshold force; controlling the robotic device to enable the tool to terminate the haptic interaction in response to determining that the force in the predetermined direction exceeds a threshold force; 15. The method of claim 14, comprising:

19. determining a direction of movement of the surgical tool; determining whether the direction of movement is toward the first haptic object; guiding the tool toward the first haptic object in response to determining that the direction of movement is toward the first haptic object; 15. The method of claim 14, comprising:

20. defining an attenuation zone for the first haptic object; determining that the tool is within the attenuation zone; controlling the robotic device to resist movement of the surgical tool through the attenuation zone; The method of claim 14 further comprising:

21. determining that the tool is passing through the attenuation zone; removing the attenuation zone in response to determining that the tool has passed through the attenuation zone; and 21. The method of claim 20, comprising:

22. 1. A method of operating a robotic device to which a tool is coupled, comprising the steps of: controlling the robotic device to constrain the tool based on a first haptic object; receiving a signal and a user defined direction; adjusting a haptic control interaction in response to the signal by adjusting a virtual dimension of the tool; The method comprising:

23. 1. A method of operating a robotic device, comprising: tracking movement of a tool coupled to the robotic device; determining a direction of movement of the tool; determining whether the direction of movement is toward a virtual control object; in response to determining that the direction of movement is toward the virtual control object, controlling the robotic device to guide the tool toward the virtual control object; The method comprising:

24. 24. The method of claim 23, wherein controlling the robotic device to guide the tool towards the virtual control object includes causing the robotic device to exert a force on the tool in the direction of movement.

25. 25. The method of claim 24, wherein the force is insufficient to independently move the tool in the direction of movement.

26. 25. The method of claim 24, wherein the force is sufficient to independently move the tools in the direction of movement.

27. The method of claim 23 , wherein determining the direction of movement of the tool comprises identifying a velocity vector that characterizes the movement of the tool.

28. tracking movement of the tool coupled to the robotic device includes tracking positions of a first point and a second point relative to the virtual control object, the first point and the second point associated with the tool; The method further comprises: controlling the robotic device to constrain the first point to the virtual control object; determining that the first point is at a threshold position along the virtual control object; controlling the robotic device to guide the second point toward the virtual control object; 24. The method of claim 23, comprising:

29. determining that the tool is in the virtual control object; controlling the robotic device to constrain the tool to the virtual control object; 24. The method of claim 23, comprising:

30. Detecting a force on the tool in a predetermined direction; determining whether the force in the predetermined direction exceeds a threshold force; in response to determining that the force in the predetermined direction exceeds a threshold force, controlling the robotic device to allow the tool to move away from the virtual control object; 30. The method of claim 29, comprising:

31. Defining an attenuation zone in the virtual object; determining that the tool is within the attenuation zone; controlling the robotic device to resist movement of the tool through the attenuation zone; 30. The method of claim 29, comprising:

32. determining that the tool is passing through the attenuation zone; removing the attenuation zone from the virtual control object in response to determining that the first point passes through the attenuation zone; 32. The method of claim 31 , comprising:

33. Receiving a signal; and adjusting a haptic control interaction in response to said signal; 30. The method of claim 29, comprising:

34. Tracking a tool coupled to the robotic device; controlling the robotic device to constrain the tool within the virtual control object; Defining a zone of the virtual object; determining that the tool is within the zone; controlling the robotic device to resist movement of the tool within the zone; A method comprising:

35. determining that the tool is passing through the zone; removing the zone from the virtual control object in response to determining that the tool is passing through the zone; 35. The method of claim 34, comprising:

36. 35. The method of claim 34, wherein controlling the robotic device to resist movement of the tool within the attenuation zone comprises controlling the robotic device to prevent a speed of the tool from exceeding a maximum speed.

37. 35. The method of claim 34, wherein controlling the robotic device to resist movement of the tool through the attenuation zone comprises controlling the robotic device to provide a force to the tool opposite a direction of movement of the tool through the zone.

38. Detecting a force on the tool in a predetermined direction; determining whether the force in the predetermined direction exceeds a threshold force; in response to determining that the force in the predetermined direction exceeds a threshold force, controlling the robotic device to allow the surgical tool to exit the virtual control object; 35. The method of claim 34, comprising:

39. 40. The method of claim 38, wherein the predetermined direction is perpendicular to a central axis of the virtual control object.

40. 1. A method of operating a robotic device to which a tool is coupled, comprising the steps of: constraining, by the robotic device, the tool to a virtual control object; Detecting a force on the tool in a substantially predetermined direction; determining whether the force in approximately the predetermined direction exceeds a threshold force; in response to determining that the force in approximately the predetermined direction exceeds a threshold force, controlling the robotic device to allow the tool to exit the virtual control object; The method comprising:

41. The method of claim 40, wherein the predetermined direction is perpendicular to an axis of the virtual control object.

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