Method and system for model-based temperature estimation in an ultrasonic instrument - Patents.com

Abstract

A method performed by a surgical system including an ultrasonic instrument having an end effector, the method determining a change in a resonant frequency of the end effector while the ultrasonic instrument is in either 1) a high power state in which the ultrasonic instrument draws a first current causing heating in the end effector or 2) a low power state in which the ultrasonic instrument draws a second current less than the first current and not causing heating in the end effector, the method determining a temperature of the end effector by applying the change in resonant frequency to a hysteresis model including a hysteresis relationship between the change in resonant frequency of the end effector and a corresponding temperature of the end effector, and outputting a notification based on the temperature.

Description

[Technical field]

[0001] Various aspects of the present disclosure relate generally to a surgical system that estimates the temperature of an ultrasonic instrument while the instrument is being used during a surgical procedure using a temperature model. Other aspects are also described. [Background technology]

[0002] Minimally-invasive surgery (MIS), such as laparoscopic surgery, uses techniques that aim to reduce tissue damage during surgical procedures. Laparoscopic procedures typically require making multiple small incisions in a patient, e.g., the abdomen, through which several surgical tools, such as an endoscope, blades, graspers, and needles, are then inserted into the patient. Gas is insufflated into the abdomen, which inflates the abdomen, thereby providing more space around the tips of the tools and making it easier for the surgeon to see (through the endoscope) and manipulate the tissue at the surgical site. MIS can be performed faster and with less surgeon fatigue using a surgical robotic system in which the surgical tools are operably attached to the distal end of a robotic arm and a control system actuates the arm and its attached tools. The tips of the tools mimic the movement of the position and orientation of a handheld user input device (UID) as the UID is being manipulated by the surgeon. A surgical robotic system may have multiple surgical arms, one or more of which have an attached endoscope and other surgical arms have attached surgical instruments for performing certain surgical actions.

[0003] Control inputs from a user (e.g., a surgeon or other operator) are captured via one or more user input devices and then translated into control of the robotic system. For example, in response to user commands, a tool drive having one or more motors can actuate one or more degrees of freedom of a surgical tool when the surgical tool is positioned at a surgical site on a patient. Summary of the Invention [Means for solving the problem]

[0004] The surgical tools used in some MIS procedures are ultrasonic instruments that use ultrasonic vibrations at their tips to rapidly generate heat for cutting and cauterizing tissue. The tips may include blades that reach high temperatures (e.g., greater than 300° C.) during a “heating” cycle in which the blade oscillates against a portion of tissue, thereby generating heat due to friction between the blade and tissue during the oscillating motion. After reaching a high temperature, the blade may be used to simultaneously incise a portion of tissue while also sealing the remaining tissue. By performing multiple tasks (e.g., cutting to incise, cauterizing, etc.), the use of tools during laparoscopic surgery reduces instrument changes and the number of instruments during a procedure.

[0005] An ultrasonic instrument may be repeatedly activated by an operator of a laparoscopic surgical system to perform several surgical tasks, such as cutting and / or long tissue sealing. After the sealing or cutting task is completed, the blade of the instrument may be stopped and enter a "cooling cycle" in which the blade begins to cool down from the elevated temperature at which it was used to perform the surgical task. At the start of the cooling cycle, the blade may still be hot due to residual heat on the blade. This heat may take some time (e.g., a significant period of time) to dissipate. As a result, while the instrument is in the cooling cycle, the operator must be careful not to touch remaining tissue to avoid inadvertently causing thermal damage to potentially sensitive tissue. However, currently, there is no mechanism to inform the operator of the laparoscopic surgical system how hot the blade is, and therefore the operator must rely on experience to guess when the blade has cooled sufficiently to continue to manipulate other tissue without causing thermal damage. With repeated starts / stops (e.g., repeated transitions between heating and cooling cycles) to perform different types of surgical tasks (e.g., longer / shorter sealing and / or cutting), it becomes even more difficult for an operator to know (or estimate) without the aid of a machine what the temperature of the blade is and when it has cooled sufficiently. Thus, there is a need to estimate (or determine) temperature information of the ultrasonic instrument in order to inform the operator of the (current or real-time) temperature status of the instrument.

[0006] The present disclosure provides a surgical system that estimates (or determines) the temperature of an ultrasonic instrument while the instrument is being used by an operator and outputs a notification that may include the estimated temperature. The system determines a change in resonant frequency of the end effector while the ultrasonic instrument is in either a "high power" state (e.g., a heating cycle) in which the ultrasonic instrument draws a first current causing (e.g., frictional) heat in the end effector, or 2) a "low current" state (e.g., a cooling cycle) in which the ultrasonic instrument draws a second current that is less than the first current and does not cause heat in the end effector. The system determines the temperature of the end effector by applying the change in resonant frequency to a temperature (e.g., hysteresis) model that includes a hysteresis relationship between the change in resonant frequency of the ultrasonic instrument's end effector (e.g., including a blade) and the corresponding temperature of the end effector. In one aspect, the model may be predefined in a controlled environment (e.g., in a laboratory). In some aspects, the temperature may be an output of the model when a change in frequency is input into the model. The system outputs a notification based on the temperature. For example, the system may display a notification (eg, a pop-up) that includes the temperature.

[0007] In one aspect, the hysteresis model includes one or more hysteresis loops, each loop having a first temperature curve having a first set of temperatures for several changes in resonant frequency and a second temperature curve having a second set of temperatures for several changes in resonant frequency. In particular, each hysteresis loop includes two (e.g., different) temperatures for changes in resonant frequency. For example, each change in resonant frequency may be associated with a respective temperature in the second set and another respective temperature in the first set that is higher than each temperature in the second set. This may be because the first temperature curve is associated with increasing end effector temperature values ​​for increasing changes in resonant frequency and the second temperature curve is associated with decreasing end effector temperature values ​​for decreasing changes in resonant frequency. In one aspect, the first temperature curve may be used to identify temperatures corresponding to changes in resonant frequency determined while the ultrasonic instrument is in a high power state and the second temperature curve may be used to identify temperatures corresponding to changes in resonant frequency determined while the ultrasonic instrument is in a low power state.

[0008] In one aspect, the end effector may include a blade that oscillates along a longitudinal axis and may include a hinged arm rotatably coupled to a joint of the end effector about a transverse axis. In some aspects, the blade oscillates (e.g., shuttles back and forth) through a first range of motion (e.g., the blade moves forward (or backward) a first distance from a starting position) while the ultrasonic instrument is in a high power state to generate heat, and 2) through a second range of motion less than the first range of motion below a frequency threshold while the ultrasonic instrument is in a low power state.

[0009] In some aspects, the surgical system may take one or more actions based on the determined temperature. For example, the system may determine a desired temperature range for the end effector and maintain the temperature of the end effector within the desired temperature range by controlling whether the ultrasonic instrument is in a high or low power state based on one or more (e.g., future) changes in the resonant frequency of the end effector. In another aspect, the system determines whether the temperature is below a temperature threshold and ceases outputting a notification in response to determining that the temperature is below the temperature threshold. For example, the notification may be displayed on a display of the surgical system and may indicate that the end effector is hot (e.g., an indication that "the end effector is hot!"). As another example, the notification may be an audible alert played by a speaker of the surgical system. In particular, the surgical system may drive the speaker 43 with an audio signal that includes an audible alert related to the temperature (e.g., playing the currently determined temperature, etc.). When the temperature falls below the threshold, this may mean that the end effector has been sufficiently cooled. As a result, the system may cease outputting notifications that may alert the system operator that the ultrasonic instrument is no longer hot.

[0010] According to another aspect of the present disclosure, a surgical system may be configured to provide closed-loop temperature control of an ultrasonic instrument. In particular, the system determines a change in resonant frequency of a blade of an end effector of the instrument. The system determines the temperature of the blade by applying the change in resonant frequency as an input to a hysteresis model that produces temperature as an output. Based on the determined temperature, the system maintains a desired temperature range of the blade by switching between a high power state in which the ultrasonic instrument draws a first current causing heat in the blade and a low power state in which the ultrasonic instrument draws a second current less than the first current and not causing heat in the blade.

[0011] In one aspect, the change in resonant frequency is determined while the ultrasonic instrument is being used by an operator during a surgical procedure and operating in either a high power state or a low power state. In another aspect, maintaining the desired temperature range includes operating in a low power state in response to determining that the determined temperature is within or above the desired temperature range, and operating in a high power state in response to determining that the determined temperature is below the desired temperature range. In some aspects, the system determines the desired temperature range via an input device (e.g., a touch-sensitive display screen, etc.) communicatively coupled to the surgical system. In another aspect, the desired temperature range is a particular user-desired temperature.

[0012] In some aspects, the system receives endoscopic video of the surgical site, performs image recognition algorithms on the endoscopic video to identify a portion of tissue within the surgical site where a surgical task will be performed by the ultrasonic instrument, and determines a desired temperature range for the blade based on the portion of tissue. In another aspect, the desired temperature range is maintained without the user using a temperature sensor.

[0013] According to another aspect of the present disclosure, a surgical system may be configured to create a hysteresis model that may be used to estimate (e.g., in real time) the temperature of an end effector while the ultrasonic instrument is being used by an operator. The system experimentally determines a first set of temperature data related to the change in resonant frequency of an end effector of an ultrasonic instrument configured to operate in either 1) a high power state in which the ultrasonic instrument draws power to generate heat for the end effector, or 2) a low power state in which the ultrasonic instrument draws less power in which the end effector does not generate heat. The system uses the first set of temperature data to determine additional temperature data related to the change in resonant frequency of the end effector as a second set of temperature data. For example, the additional temperature data may be determined using one or more methods, such as interpolation or polynomial fit techniques. The system uses the first and second sets of temperature data to generate a hysteresis model that includes (or defines) a hysteresis relationship between the change in resonant frequency and the temperature of the end effector.

[0014] The above summary does not include an exhaustive list of all aspects of the present disclosure. The present disclosure is intended to include all systems and methods that can be practiced from all suitable combinations of the various aspects summarized above, as well as those disclosed in the following "Description of the Preferred Embodiments" and particularly those pointed out in the "Claims". Such combinations may have certain advantages not specifically described in the above summary. [Brief description of the drawings]

[0015] The embodiments are illustrated by way of example, and not by way of limitation, in the figures of the accompanying drawings, in which like reference symbols indicate similar elements. It should be noted that references to "an" or "one" embodiment in this disclosure are not necessarily to the same embodiment, but rather they mean at least one. Also, for purposes of brevity and reducing the total number of figures, a given figure may be used to illustrate features of more than one embodiment, and not all elements in a figure may be required for a given embodiment. [Figure 1] 1 shows a pictorial representation of an exemplary surgical system in an operating room. [Diagram 2] 1 shows a pictorial diagram of an ultrasonic instrument and generator according to one aspect of the present disclosure. [Diagram 3] 3 illustrates an end effector of the ultrasonic instrument of FIG. 2. [Figure 4] FIG. 1 is a block diagram of a surgical system according to one aspect. [Diagram 5] 1 illustrates a graphical representation of a hysteresis loop of a hysteresis model according to one embodiment. [Figure 6] 1 shows a graphical representation of a hysteresis loop including several inner temperature curves, according to one embodiment. [Figure 7] FIG. 1 is a flow diagram of a process for estimating the temperature of an end effector of an ultrasonic instrument while the instrument is being used by an operator of a surgical system. [Figure 8] FIG. 1 is a flow diagram of a process for determining the temperature of an ultrasonic instrument using a hysteresis model. [Figure 9] 1 illustrates a graphical representation of temperatures determined while an ultrasonic instrument is in use, according to one embodiment. [Figure 10] 1 illustrates several stages of a display of a surgical system showing actions taken by an end effector of an ultrasonic instrument and showing notifications based on the determined temperature of the end effector. [Figure 11] FIG. 1 is a flow diagram of a process for maintaining a desired temperature of an ultrasonic instrument. [Figure 12] FIG. 1 is a flow diagram of a process for creating a hysteresis model that defines the hysteresis relationship between temperature and change in resonant frequency. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] Some aspects of the present disclosure will now be described with reference to the accompanying drawings. Whenever the shape, relative position, and other aspects of parts described in a given aspect are not explicitly defined, the scope of the disclosure herein is not limited to only the parts shown, which are intended for illustrative purposes only. Also, although numerous details are described, it is understood that some aspects can be practiced without these details. In other cases, well-known circuits, structures, and techniques have not been shown in detail so as not to obscure the understanding of this description. Furthermore, unless the meaning is clearly to the contrary, all ranges described herein are considered to include the endpoints of each range.

[0017] FIG. 1 shows a pictorial view of an exemplary surgical system (which may hereafter be referred to as the "system") 1 in an operating room. The system 1 includes a user console 2, a control tower 3, and one or more surgical robotic arms 4 on a surgical robot table (surgical table or surgical platform) 5. In one aspect, the arms 4 may be mounted to a table or bed on which a patient lies, as shown in the example of FIG. 1. In one aspect, at least some of the arms 4 may be configured differently. For example, at least some of the arms may be mounted to another suitable structural support, such as a ceiling, a side wall, or a cart separate from the table. The system 1 may incorporate any number of devices, tools, or accessories used to perform surgery on a patient 6. For example, the system 1 may include one or more surgical tools (instruments) 7 used to perform the surgery (surgical procedure). The surgical tools 7 may be end effectors for performing the surgical procedure that are attached to the distal end of the surgical arms 4.

[0018] Each surgical tool 7 may be manipulated manually, robotically, or both during surgery. For example, the surgical tool 7 may be a tool used to enter, view, or manipulate the internal anatomy of the patient 6. In one aspect, the surgical tool 7 is a grasper capable of grasping the patient's tissue. The surgical tool 7 may be controlled manually by a bedside operator 8 or robotically via actuated movement of a surgical robot arm 4 to which the surgical tool is attached. For example, when manually controlled, the operator may (e.g., physically) hold a portion of the tool (e.g., a handle) and manually control the tool by moving the handle and / or pressing one or more input controls (e.g., buttons) on the tool (e.g., the tool's handle). In another aspect, when robotically controlled, the surgical system may manipulate surgical tool-based user inputs (e.g., received via a user console 2 as described herein).

[0019] In general, a remote operator 9, such as a surgeon or other operator, may use the user console 2 to operate the arm 4 and / or attached surgical tool 7 remotely, e.g., during teleoperation. The user console 2 may be located in the same operating room as the rest of the system 1, as shown in FIG. 1. However, in other environments, the user console 2 may be located in an adjacent or nearby room, or in a remote location, e.g., in a different building, city, or country. The user console 2 may include one or more components, such as a seat 10, one or more foot-operated controls (or foot pedals) 13, one or more (handheld) user input devices (UIDs) 14, and at least one display 15. The display may be configured to display, e.g., a view of a surgical site inside the patient 6. The display may be configured to display image data (e.g., still images and / or video). In one aspect, the display can be any type of display, such as, for example, a liquid crystal display (LCD), a light-emitting diode (LED) display, an organic LED (OLED) display, etc. In some aspects, the display can be a 3D immersive display for displaying a 3D (surgical) representation. For example, during a surgical procedure, one or more endoscopic cameras can capture image data of a surgical site that the display presents to a user in 3D. In one aspect, the 3D display can be a naked eye stereoscopic display that provides a 3D perception to a user without the need for special glasses. As another example, the 3D display can be a stereoscopic display that uses glasses to provide a 3D perception (e.g., via active shutters or polarization).

[0020] In another aspect, the display 15 may be configured to display in one final graphical user interface (GUI) that may provide informative and / or interactive content to assist the user in performing a surgical procedure with one or more instruments in the surgical system 1. For example, some of the displayed content may include image data captured by one or more endoscopic cameras, as described herein. In another aspect, the GUI may include selectable UI items that, when manipulated by the user, may cause the system to perform one or more actions. For example, the GUI may include UI items as interactive content for switching control between robotic arms. In one aspect, to interact with the GUI, the system may include an input device, e.g., a keyboard, a mouse, etc. In another aspect, a user may interact with the GUI using the UID 14. For example, a user may manipulate the UID (e.g., with a cursor) to navigate through the GUI, and may hover the cursor over a UI item and manipulate the UID (e.g., select a control or button) to make a selection. In some aspects, the display may be a touch-sensitive display screen. In this case, the user may make a selection by navigating and selecting through touching the display. In some aspects, any method may be used to navigate and / or select UI items.

[0021] As shown, a remote operator 9 sits on seat 10 and views user display 15 while operating foot-operated control 13 and handheld UID 14 to remotely control arm 4 and one or more surgical tools 7 (mounted at the distal end of arm 4).

[0022] In some variations, a bedside operator 8 may also operate the system 1 in a "bed-facing" mode, where the bedside operator 8 (user) is at the side of the patient 6 and is manipulating a robotically driven tool (end effector attached to arm 4) simultaneously with a manual laparoscopic tool, for example, with a handheld UID 14 held in one hand. For example, the bedside operator's left hand may be manipulating the handheld UID to control the robotic components, while the bedside operator's right hand may be manipulating a manual laparoscopic tool. Thus, in these variations, the bedside operator 8 may perform both robotically assisted minimally invasive surgery and manual laparoscopic surgery on the patient 6.

[0023] During an exemplary procedure, the patient 6 is sterilely prepped and draped to achieve anesthesia. Initial access to the surgical site may be performed manually while the arms of the system 1 are in a stowed or retracted configuration (thereby facilitating access to the surgical site). Once access is complete, initial positioning or preparation of the system 1 including its arms 4 may be performed. A remote operator 9 at the user console 2 then proceeds with the procedure by utilizing the foot control 13 and UID 14 to operate the various end effectors and possibly an imaging system to perform the procedure. Manual assistance may also be provided at the procedure bed or table by sterile gowned bedside personnel, such as a bedside operator 8, who may perform tasks such as retracting tissue, performing manual repositioning, and replacing one or more tools of the robotic arms 4. Non-sterile personnel may also be present to assist the remote operator 9 at the user console 2. Once the procedure or surgery is completed, the system 1 and user console 2 may be configured or set to a state to facilitate post-operative procedures such as cleaning or sterilization and entering or printing medical records via the user console 2.

[0024] In one aspect, the remote operator 9 holds and moves the UID 14 to provide input commands to drive (move) one or more robotic arm actuators 17 (or drive mechanisms) of the system 1 for remote operation. The UID 14 may be communicatively coupled to the rest of the system 1, for example, via the console computer system 16 (or host). The UID 14 may generate spatial state signals corresponding to the movements of the UID 14, e.g., the position and orientation of the UID's handheld housing, which may be input signals for controlling the movement of the robotic arm actuators 17. The system 1 may use control signals derived from the spatial state signals to control the proportional movement of the actuators 17. In one aspect, a console processor of the console computer system 16 receives the spatial state signals and generates corresponding control signals. Based on these control signals, which control how the actuators 17 are energized to drive segments or links of the arm 4, the movements of the corresponding surgical tools attached to the arm may mimic the movements of the UID 14. Similarly, interaction between the remote operator 9 and the UID 14 may generate grip control signals that, for example, cause the jaws of a grasper on the surgical tool 7 to close and grip tissue of the patient 6 .

[0025] System 1 may include several UIDs 14, where for each UID a respective control signal is generated that controls the actuators of the respective arms 4 and the surgical tools (end effectors). For example, the teleoperator 9 may move a first UID 14 to control the movement of an actuator 17 in the left robotic arm, where that actuator responds by operating joints, gears, etc. in that arm 4. Similarly, movement of a second UID 14 by the teleoperator 9 controls the movement of another actuator 17, which in turn drives other joints, gears, etc. in system 1. System 1 may include a right arm 4 on the right side of a patient fixed to a bed or table, and a left arm 4 on the left side of the patient. The actuators 17 may include one or more motors that are controlled to drive the rotation of the joints of the arm 4 to change the orientation of, for example, an endoscope or grasper of a surgical tool 7 attached to that arm, relative to the patient. The movement of several actuators 17 in the same arm 4 can be controlled by spatial state signals generated from a particular UID 14. The UIDs 14 can also control the movement of respective surgical tool graspers. For example, each UID 14 can generate a respective grasp signal to control the movement of an actuator, such as a linear actuator, that opens and closes the jaws of a grasper at the distal end of the surgical tool 7 to grasp tissue within the patient 6.

[0026] In some embodiments, communication between the surgical robot table 5 and the user console 2 may be through a control tower 3, which may translate user commands received from the user console 2 (more specifically, from the console computer system 16) into robotic control commands sent to the arm 4 on the surgical table 5. The control tower 3 may also transmit status and feedback from the surgical table 5 to the user console 2. The communication connections between the surgical table 5, the user console 2, and the control tower 3 may be via wired (e.g., fiber optic) and / or wireless links using any suitable of a variety of wireless data communication protocols, for example, the BLUETOOTH protocol. Any wired connections may optionally be built into the floor and / or walls or ceiling of the operating room. The system 1 may provide video output to one or more displays, including displays in the operating room as well as remote displays accessible via the Internet or other networks. The video output or feed may also be encrypted to ensure privacy, and all or portions of the video output may be stored on a server or electronic medical record system.

[0027] 2 shows a pictorial diagram of an ultrasonic instrument 20 and generator 25 according to one embodiment of the present disclosure. As shown, the ultrasonic instrument is a handheld laparoscopic tool configured to perform ultrasonic surgical procedures (e.g., cutting and sealing tissue) based on manual manipulation of the instrument (e.g., of hand grip 21) by an operator (e.g., a surgeon). The ultrasonic instrument is coupled (e.g., via a cable) to a generator that allows the ultrasonic instrument to operate in one or more power states, as described herein.

[0028] In accordance with aspects of the present technology, an ultrasonic instrument includes a hand grip (e.g., including a tool driver) 21, a cannula 22, and an end effector 23 (e.g., which may be coupled to the shaft of the instrument) that is loaded into the cannula.

[0029] The hand grip 21 is positioned to be held by an operator and allows the operator to manipulate the ultrasonic instrument (e.g., its end effector 23) during a surgical procedure. In one embodiment, the hand grip may include one or more inputs (e.g., a trigger, one or more buttons, etc.) that allow the operator to control the ultrasonic instrument. For example, the instrument may include a trigger that generates a control signal in response to a user input by pulling the trigger with one or more fingers while holding the hand grip. In one embodiment, the trigger may be positioned to manipulate the end effector (e.g., by adjusting the position of the hinged arm 31 shown in FIG. 3). In another embodiment, the hand grip may include one or more inputs to change the power state of the instrument.

[0030] As described herein, the hand grip may include a tool drive arranged to drive the end effector 23 of the ultrasonic instrument. In particular, the tool drive may include a (e.g., linear) motor or actuator arranged to vibrate (or rock) the end effector at one or more frequencies (e.g., very high (ultrasonic) frequencies and low frequencies). In some aspects, the tool drive is configured to vibrate the end effector such that a portion of the end effector (e.g., a blade) moves back and forth along one or more axes. In particular, the tool drive may vibrate the end effector through one or more ranges of motion, and through each range of motion, the end effector may be displaced a different distance from a starting (or originating) position. Further description of how the end effector vibrates is described herein. In another aspect, the tool drive may include an ultrasonic transducer configured to vibrate the end effector according to an input voltage / current (e.g., applied by generator 25).

[0031] As previously described, an ultrasonic instrument may include an end effector 23 and a tool driver 21. In one aspect, the ultrasonic instrument may be separate from (and removably coupled to) the tool driver. In that case, the ultrasonic instrument referred to herein may be an end effector that may be coupled to a hand grip (e.g., to the tool driver via a cannula in the hand grip). Specifically, a cannula may be coupled to the hand grip, which receives and guides the ultrasonic instrument (e.g., its shaft) for coupling to the instrument. By being separate from the hand grip, this may allow multiple different tools to be coupled to the hand grip. In this case, the cannula 22 may receive and guide one or more surgical instruments, e.g., an endoscope, a stapler, etc.

[0032] As described herein, the surgical system 1 includes an ultrasonic instrument 20 configured to generate heat based on vibration of its end effector 23. In another embodiment, the instrument can be any type of energy (e.g., laparoscopic) tool designed to generate heat.

[0033] As described thus far, the ultrasonic instrument 20 may be a handheld laparoscopic instrument that may be manually held and operated by an operator. In another embodiment, the instrument may be part of a surgical robotic arm. Specifically, the ultrasonic instrument may be coupled to a robotic arm and powered by a generator as described herein. For example, the ultrasonic instrument may be coupled to a distal end of a robotic arm (e.g., arm 4 in FIG. 1 ), which includes several components that allow the robotic arm to be controlled by an operator. For example, the surgical robotic arm 104 may include multiple links and multiple actuation joint modules for actuating the multiple links relative to one another. The joint modules may include various types, such as pitch joints or roll joints, which may substantially constrain the movement of adjacent links relative to others about a particular axis. The multiple joint modules of the robotic arm 104 may be actuated to position and orient the ultrasonic instrument for robotic surgery. In one embodiment, the ultrasonic instrument may be coupled to the distal end via a tool drive that is arranged to actuate the end effector 23 of the instrument.

[0034] When an ultrasonic instrument is coupled to a robotic arm, movement and manipulation of the ultrasonic instrument may be accomplished via one or more user controls (e.g., UID, foot pedals, etc.) coupled to the surgical system. For example, the UID may be arranged to open and close the gripper 23 of the ultrasonic instrument and / or to adjust the spatial position (in space) of the gripper based on user input (e.g., the position of the UID).

[0035] Referring to Figure 3, this figure shows the end effector 23 of the ultrasonic instrument of Figure 2. Specifically, this figure shows that the end effector is a grasper (or gripping device) that is received through a cannula 22 and includes a blade 30 (e.g., as one jaw) and a hinged arm (or jaw) 31 that is rotatably coupled to a joint (or robotic wrist) 32. In particular, the blade is received (and extends) through the cannula and is positioned to couple to a tool drive (e.g., of the hand grip 21) so that the blade oscillates further back within the cannula. The hinged arm 31 is rotatably coupled (at joint 32) to the cannula 22 and is positioned to rotate. The grasper is positioned to open and close based on the rotational position of the hinged arm about the joint's axis of rotation (e.g., the Z-axis) relative to the blade (and / or cannula). For example, the grasper is positioned to open (or be in an open position) when the hinged arm is rotated (e.g., a threshold distance) away from the blade. While in this position, the end effector can be oriented such that an object, such as tissue, can be disposed between the blade and the hinged arm (e.g., by moving the end effector around the object). The grasper can close (or be in a closed position) when the hinged arm is rotated (e.g., within a threshold distance) towards the blade, whereby the grasper can grasp an object between the blade and the hinged arm. As described herein, the hinged arm can be positioned to apply pressure against a grasped object (e.g., crushing the object between the jaws) to grip the object and / or make an incision on the object.

[0036] As described herein, the blade 30 is a jaw of a grasper. In particular, the blade is a jaw that cannot rotate (e.g., about the Z axis) relative to the end effector. The blade can be arranged to oscillate along its longitudinal axis (e.g., the Y axis) while the ultrasonic instrument is in a high power state (or mode) to generate heat. In particular, the blade can be driven (e.g., by a tool drive in the hand grip 21) to move back and forth (e.g., linearly) along the longitudinal axis of the end effector (and through a cannula as described herein) to repeatedly displace the blade 30 at a (e.g., constant) frequency. Specifically, the blade can oscillate (e.g., move back and forth) through a range of motion (or displacement) in which the blade moves a distance (e.g., forward or away from the end effector) from a starting position and then moves back the same distance. In one aspect, the range of motion can be the distance the blade moves from a starting position to an extended position. In another aspect, the range of motion can be the distance that the blade moves back and forth.

[0037] As described herein, the blade may generate frictional heat while vibrating against an object. Specifically, the blade may contact tissue while the grasper is crushing the tissue between the two jaws and may vibrate against the tissue. As the blade vibrates, the end effector may cut and / or cauterize the tissue as described herein. In one aspect, the blade may vibrate differently (e.g., through different ranges of motion) based on the power state of the ultrasonic instrument (e.g., how much power is provided). Further description of the vibrating blade and power states of ultrasonic instruments are described herein.

[0038] Returning to FIG. 2 , the generator 25 is configured to control and provide power to the ultrasonic instrument to control (e.g., heat) the end effector 23 while the instrument is coupled to the generator and in use by an operator (e.g., during a laparoscopic procedure to manipulate tissue and / or perform one or more surgical tasks on tissue, e.g., to cut, seal blood vessels, and / or cut, grasp, and dissect tissue). In particular, the generator may provide power to the ultrasonic instrument such that the surgical system 1 (e.g., its ultrasonic instrument) may operate in one of one or more power states. For example, the generator may provide power to the instrument such that the ultrasonic instrument is in a “high power” state (or “heat cycle”), in which the instrument draws power (or current) from the generator (e.g., at a particular voltage) to generate heat in the end effector 23. For example, the generator may provide a (e.g., first) electrical current (or input current) to a hand grip (e.g., a tool drive of the hand grip) of the ultrasonic instrument, which may use this electrical current to drive the blade 30 to oscillate (or swing) through a (first) range of motion (and at a particular frequency). Frictional heat may be generated by the end effector while the blade of the end effector is oscillated through this range of motion against an object, such as tissue, as described herein. In another aspect, the ultrasonic instrument may be placed to operate in a "low power" state (or "cooling cycle"), where the ultrasonic instrument no longer draws (enough or as much) power provided by the generator to heat the end effector while the instrument was in a high power state. Specifically, while in this state, the generator may be configured to provide less power to the ultrasonic instrument than was provided by the generator while the instrument was in a high power state, such that the end effector does not generate heat (e.g., when in contact with an object). In particular, the generator may provide a current (e.g., a second current) to the ultrasonic instrument that is less than the (first) current provided by the generator while the instrument is operating in a high power state, and as a result, this does not cause heat in the end effector (or as little heat as when the ultrasonic instrument is in a high power state).As a result, the ultrasonic instrument may begin to cool when entering a low power state from a high power state. Eventually, if kept in the low power state, the ultrasonic instrument will cool down (at least) to a threshold temperature (e.g., room temperature). In one aspect, the second current may be less than a predefined threshold current. In one aspect, the blade may vibrate at the same frequency in the low power state as in the high power state. In another aspect, the blade may vibrate within an allowed frequency range.

[0039] As a result, due to the smaller current provided to the instrument while in the low power state, the blade of the end effector may be driven by the tool driver 21 differently than when the instrument is in the high power state. In particular, the blade may oscillate through a range of motion that is different from the range of motion through which the blade oscillates while the instrument is in the high power state. For example, while in the high power state, the blade may oscillate through a first (e.g., high) range of motion, which may cause the blade to heat up when pressed against an object, while while in the low power state, the blade may oscillate through a second (lower) range of motion that may be smaller than the first range of motion (e.g., the blade is displaced less along the longitudinal axis than the first range of motion). In some aspects, the second range of motion may be smaller than a minimum threshold (e.g., a threshold above which the blade will generate heat if it oscillates above the minimum threshold). In one aspect, the end effector may not generate frictional heat while oscillating through this lower range of motion and while pressed against an object such as a blood vessel. In one aspect, the resonant frequency is maintained within an acceptable range regardless of what power state the instrument is operating in.

[0040] In one aspect, the difference in vibration of the end effector may be based on the amount of power being drawn by the ultrasonic instrument while in the different states. For example, the range of motion displaced while the blade is oscillating may be based on (e.g., proportional to) the power drawn by the instrument, whereby more power drawn by the instrument may cause the blade to oscillate over a higher range of motion. Conversely, while the ultrasonic instrument is in a low power state, the instrument may draw less power, causing the blade to oscillate less (than while the instrument is in a low power state). As a result of the oscillation over a smaller displacement, the blade may not generate frictional heat (e.g., while in contact with tissue). In another aspect, the blade may be in a low power state and generate some frictional heat while in contact with an object, but less than the heat generated while the instrument is in a high power state. In this case, this generated frictional heat may not be sufficient to cut and / or seal tissue. In some aspects, as a result of operating in the low power state, the end effector of the ultrasonic instrument may enter a cooling cycle, whereby heat generated by the end effector while the instrument was in the high power state dissipates (e.g., over a period of time). In another aspect, the blade may not vibrate (e.g., the tool drive 21 may not drive the blade) while in this low power state.

[0041] In one aspect, the system may enter (or operate in) at least one of the power states based on a user input (e.g., received by the generator 25). In particular, the generator may provide power to the ultrasonic instrument based on receiving a user input to one or more input devices (e.g., input to the foot petals, a UID controlled by an operator and communicatively coupled to the system 1, and / or an input at the hand grip 21 of the ultrasonic instrument). The power provided based on the user input may place the ultrasonic instrument in a high power state in which the ultrasonic instrument draws power from the generator to heat the end effector 23 (e.g., the blade 30 of the end effector 23). For example, when the generator receives a (first) user input (e.g., by the operator pulling or pressing a trigger on the hand grip 21), the generator may provide an electric current to the ultrasonic instrument (e.g., the tool drive 21 of the ultrasonic instrument), which uses the electric current to drive the end effector, as described herein. Thus, if the trigger controls the hinged arm of the end effector, the generator is configured to provide current when the hinged arm is moved (e.g., at least a threshold distance toward the blade 30). In another aspect, the system may enter a lower power state based on another (e.g., a second) user input (e.g., receiving input from a different input device coupled to the generator, such as a foot pedal).

[0042] In some aspects, the ultrasonic instrument may be arranged to switch between a high power state and a low power state. As described herein, the instrument may operate in the high power state while the generator receives a user input (e.g., a user pulling or pressing a trigger on a hand grip). The instrument may operate in the low power state in response to the generator not receiving a user input. For example, the ultrasonic instrument may switch from a high power state to a low power state in response to a user releasing a trigger on a hand grip, and the generator may transition between the two states). In one aspect, as described herein, the instrument may operate in a low power state while an operator is not actively using the instrument to perform ultrasonic instrument operations. Specifically, the system may enter a low power state, but no user input is received to one or more input devices used by the operator to enter the high power state. However, once the operator desires to actively use the ultrasonic instrument, the ultrasonic instrument may switch back to the high power state (e.g., in response to a user input). In another aspect, the instrument may operate in the low power state in response to receiving a user input (e.g., a user pressing a button on the UID). In another aspect, the instrument may operate in this state for a period of time. As described herein, the surgical system is configured to determine the temperature of the end effector while in the low power state (e.g., after switching from the high power state) to inform the operator of the temperature that may be high due to the instrument operating in the high power state. Once the end effector cools to a certain temperature (e.g., below a predefined temperature), the generator may shut down the instrument by ceasing to provide a lower current since at this temperature the end effector may not cause thermal damage when in contact with tissue.

[0043] In one aspect, the generator may provide different levels of current to heat the blade, which may be based on user input. For example, the generator may receive a first user input (e.g., from one petal coupled to the generator) and, in response, provide a maximum (allowable) amount of current to the ultrasonic instrument. The ultrasonic instrument may then drive the end effector through a maximum (e.g., predefined) range of motion, which may result in the end effector generating heat at a (first) high temperature. However, when the generator receives a second user input (e.g., from another petal coupled to the generator), the generator may provide a lower amount of current to the ultrasonic instrument. As a result, the ultrasonic instrument may draw less power to vibrate the end effector through a (second) lower range of motion, which may be lower than the first range of motion at which the blade vibrates in response to the first user input. However, this lower range of motion may cause the end effector to heat at a lower temperature than the first temperature of the end effector when the ultrasonic instrument draws more current (in response to the generator receiving a first user input). By heating the end effector to different temperatures, different types of tissue may be cut and / or cauterized. For example, fatty tissue may require the end effector to be hotter (having a first temperature) while thinner (and less fatty) tissue may require less heat (having a second temperature) to cut and / or cauterize the tissue. In another aspect, the generator may be configured to provide one current while in a high power state (e.g., drive the end effector through a first high range of motion).

[0044] As described herein, an ultrasonic instrument may be activated (e.g., may operate in a high power state) based on whether the end effector is in a closed position to grasp an object (e.g., a portion of tissue). For example, an ultrasonic instrument may be activated (e.g., by a user) such that the ultrasonic instrument may operate in a high power state to draw sufficient current to cause heat in the end effector. In particular, the generator may activate the ultrasonic instrument upon receiving a user input to close the end effector (e.g., to move the hinged arm 31 within a distance of the blade 30). When a user input to move the hinged arm is received, the generator may be configured to provide (e.g., sufficient) power to activate the instrument, as described herein. In some aspects, the generator may activate the instrument based on a determination that the hinged arm and / or the blade are in contact with an object. For example, an ultrasonic instrument may include one or more sensors (e.g., force sensors) that detect the presence of an object and / or that an object is in contact with both arms. Upon making this determination, the generator may provide a first electrical current to cause the blade to oscillate in order to generate heat in the blade.

[0045] In one aspect, the surgical system (e.g., its generator) may be configured to determine one or more characteristics of the ultrasonic instrument while the instrument is in one or more of the power states. For example, the generator may be configured to track (or monitor) characteristics such as the input voltage, input current, resonant state, and / or resonant frequency of the ultrasonic instrument. In one aspect, the generator may be configured to monitor at least some of these characteristics of the instrument while the instrument is operating in a high power state. However, unlike conventional systems that cannot determine characteristics while the ultrasonic instrument is in a cooling cycle because the instrument is turned off (e.g., no power is being provided by the generator), the surgical system of the present disclosure can determine characteristics while the instrument is in a low power state (or cooling cycle) because the instrument draws at least some power. For example, the generator may determine the resonant frequency of the end effector (e.g., the blade 30 of the end effector) while in a low power state.

[0046] In one aspect, at least one of the characteristics of the ultrasonic instrument may be determined from other characteristics. For example, one characteristic may be a change in resonant frequency of the (blade of) the end effector. The generator may determine the change based on one or more (e.g., previously) monitored resonant frequencies. For example, the change in resonant frequency may be determined based on a comparison between (at least) one previously determined frequency and a most recently determined resonant frequency. In another aspect, the change in resonant frequency may be an average change over a period of time (or over several samples taken by the generator).

[0047] In one aspect, the surgical system may include additional components. For example, the system may include a cable connecting the generator to an ultrasonic instrument (e.g., an ultrasonic transducer configured to convert a current drive signal into mechanical vibrations). In one aspect, the ultrasonic transducer may be connected to a waveguide that is connected to the blade 30 of the end effector 23.

[0048] As also shown, the generator 25 includes a display 24 arranged to disclose information regarding the operation of the ultrasonic instrument. For example, the display may present temperature information, what state the ultrasonic instrument is currently in, and one or more of the characteristics described herein.

[0049] 4 is a block diagram of a surgical system 1 according to one embodiment. The system includes an ultrasonic instrument 20, a generator 25, a controller 40, a display 15, and a speaker 43 (which may be a stand-alone speaker or part of the system's electronic devices, such as a user console 2). In one embodiment, the system may include more or fewer elements, such as having more than one display and / or no speaker.

[0050] In one aspect, the controller 40 may be a dedicated processor, such as an application-specific integrated circuit (ASIC), a general-purpose microprocessor, a field-programmable gate array (FPGA), a digital signal controller, or a set of hardware logic structures (e.g., filters, arithmetic logic units, and dedicated state machines). In one aspect, the controller may be part of an electronic device, such as the console computer system 16, the tower 3, and / or the user console 2. Although illustrated as a single component, in one aspect, the controller may comprise one or more electronic components (e.g., processor, memory, etc.) communicatively coupled on a single electronic device (such as the console computer 16) or across multiple devices (e.g., communicating via a wireless computer network). In some aspects, the controller may be part of a separate device, such as part of a remote server in communication with one or more electronic devices. In another aspect, the controller may be part of the generator 25 (e.g., may be at least partially integrated within the generator 25). In that case, at least some of the other elements (e.g., the speaker and display) may also be part of (integrated within) the generator, and as a result, at least some of the operations performed by the controller described herein may be performed by the generator.

[0051] As described herein, the controller is configured to perform temperature estimation operations for the surgical system 1 to determine a (e.g., real-time) temperature of an ultrasonic instrument (e.g., its end effector) while the instrument is being used by an operator of the system. In particular, the controller may determine the temperature based on one or more characteristics (e.g., resonant frequency) of the ultrasonic instrument determined while the instrument is in a high power state (e.g., actively being used by an operator to perform a surgical task such as cutting and / or sealing tissue) and / or while the instrument is in a low power state (e.g., not actively being used by an operator to perform a surgical task). In particular, the controller may be configured to apply the one or more characteristics to a temperature (e.g., hysteresis) model 45 stored in memory 44. Further description of operations performed by the controller to estimate temperature is described herein. At least some of the operations performed by the controller may be implemented in software (e.g., as instructions) stored in a memory of the surgical system (and / or stored in a memory of the controller) and executed by the controller, and / or may be implemented by hardware logic structures. In one aspect, at least some of the operations performed by the controller may be performed in real-time (e.g., while the instrument is operating in one of one or more power states).

[0052] As shown, the generator may receive a user input (e.g., via one or more electronic devices coupled to the generator) to cause the generator to perform one or more actions. For example, a user input may be received via an ultrasonic instrument (e.g., when a user pulls a trigger on a hand grip) to cause the generator to provide a current that switches the ultrasonic instrument from a low power state to a high power state, as described herein.

[0053] The storage (or memory) 44 stores a temperature model 45 for estimating (or determining) the temperature of the ultrasonic instrument end effector 23 from one or more characteristics. In one aspect, the temperature model may be a model predefined in a controlled environment (e.g., a laboratory). Further discussion of defining the model is provided herein. In some aspects, the model may be a hysteresis model that includes (or defines) a hysteresis relationship between one or more characteristics of the ultrasonic instrument and one or more (corresponding) temperature values ​​of the ultrasonic instrument 20 (e.g., its end effector 23). For example, the model may define the temperature (e.g., nonlinear behavior of temperature) of the instrument end effector (e.g., the blade of the end effector) with respect to a characteristic such as one or more changes in the resonant frequency of the end effector (e.g., the blade of the end effector). For example, when the blade of an ultrasonic instrument is heated during an activation (heating) cycle (e.g., while the instrument is in a high power state), the material properties (e.g., stiffness) of the blade change, which is reflected as a change in the resonant frequency of the blade. These changes in resonant frequency are reversed when the blade goes into a cooling cycle (e.g., while in a low power state) to cool (e.g., to room temperature), but the resonant frequency does not follow exactly the same rate and path as it did during the heating cycle. As a result, a hysteretic relationship exists between the resonant frequency change of the blade and the blade temperature. Further explanation of this hysteretic relationship is provided herein.

[0054] In one aspect, the hysteresis temperature model 45 can be any hysteresis model that defines the relationship between resonant frequency and temperature. For example, the model can be a discretized Preisach model of hysteresis that models the output function as a weighted sum of individual relay functions called hysterons. In one aspect, each hysteron γ has separate turn-on and turn-off thresholds (e.g., α and β, respectively) and contributes a “+1” or “−1” value (when turning on and off, respectively) to the summation depending on the value of the input. In one aspect, the model is a γ α1β1 ...γ αnβnIn one embodiment, each hysterone may be associated with a (e.g., different) weighting coefficient μ that defines the individual contribution of each hysterone to the summed weight. Thus, each hysterone γ α1β1 ...γ αnβn are the respective weight coefficients μ α1β1 ...μ αnβn In some aspects, at least some of the hysterons may include different (or the same) turn on / off thresholds and / or weighting coefficients. With respect to the temperature model, the turn on / off thresholds may correspond to a change, such as an increase (or positive) or decrease (or negative) change in the resonant frequency of the end effector. The change in the resonant frequency may then be input into the model, and the model outputs the temperature of the end effector, which may be the sum of one or more hysterons (e.g., their weighted coefficients) of the hysteresis model. Further discussion of using models to determine the temperature of the end effector is provided herein.

[0055] In some embodiments, the hysteresis model 45 may include (or define) a hysteresis loop having temperature values ​​of the ultrasonic instrument's end effector versus changes in the resonant frequency of the end effector (e.g., during use of the instrument). This is due to the hysteresis relationship between temperature and changes in resonant frequency, as described herein. Referring now to FIG. 5, this figure shows a graphical representation of a main hysteresis loop 50 of the model according to one embodiment. The loop includes a main increasing (or first) temperature curve 51 and a main decreasing (or second) temperature curve 52, both having (at least some) different temperature values ​​versus (e.g., the same or similar) changes in the resonant frequency of the end effector.

[0056] In one aspect, the hysteresis loop 50 represents the temperature behavior of the end effector while the ultrasonic instrument is in use. Specifically, a first temperature curve 51 represents the temperature behavior of the end effector when the end effector reaches a minimum temperature T min Starting from the maximum temperature of the end effector, T maxrepresents several temperature values ​​of the end effector during a heating cycle up to t max may be a predefined temperature as defined by the end effector manufacturer's specifications. As shown, a first curve 51 represents the starting change in resonant frequency ΔRF during a heating cycle. Heat where the end effector temperature is at a minimum temperature T min In one embodiment, ΔRFstart Heat may represent the change in resonant frequency of the end effector when the ultrasonic instrument goes into a heating cycle (e.g., is activated) to perform a surgical task on a portion of tissue (e.g., when the ultrasonic instrument goes into a high power state). Heat may be the change in resonant frequency after a period of time from when the instrument is activated. Curve 51 increases and the temperature values ​​increase as the change in resonant frequency of the end effector increases due to the increased heat generated by the end effector. Curve 51 represents the heating behavior of the end effector from a minimum to a maximum temperature while the ultrasonic instrument is in a high power state and generating heat in the end effector. Thus, the temperature values ​​of curve 51 increase for an increasing change in resonant frequency.

[0057] The second temperature curve 52 is a graph showing the temperature at which the end effector max When the end effector is at a minimum temperature T min As shown, a second curve 52 represents several temperature values ​​of the end effector during the cooling cycle until the end effector is cooled to T max The starting change in resonant frequency during (or at the start of) a cooling cycle that is at or near Cool In one embodiment, ΔRFstart Coolmay represent the change in resonant frequency of the end effector once the ultrasonic instrument is no longer active (or after a period of time has passed since it was no longer active) and is in a low power state. For example, this change may occur after a user input is received to switch the end effector from a high power state to a low power state, causing the end effector to begin a cooling cycle. As the change in the resonant frequency of the end effector decreases, curve 52 (or the temperature value of the curve) decreases. The second curve 52 represents the change in resonant frequency of the end effector once T min 5. Thus, the temperature values ​​of curve 52 decrease for a decreasing change in resonant frequency. In one embodiment, each change in resonant frequency (along the X-axis) is associated with two temperature values ​​(e.g., along the Y-axis), one temperature value along the main decreasing temperature curve 52 and another temperature value along the main increasing temperature curve 51 that is greater than the temperature value along curve 52.

[0058] In one aspect, this hysteresis relationship between the resonant frequency change and the end effector temperature during the heating and cooling cycles can be attributed to the delay caused by the accumulation of heat capacity and the thermal gradient that occurs across the end effector (e.g., the blade). Specifically, when the blade is heated, the temperature of the entire structure increases rapidly, causing a shift in the resonant frequency, but when it cools down, the blade temperature decreases, but the residual heat remaining in the rest of the structure slows down the progress of the recovery of the resonant frequency. Thus, both curves form a hysteresis loop following different temperature patterns.

[0059] In one aspect, the change in resonant frequency may be a continuous change in the resonant frequency of the blade of the end effector during use. For example, as the blade heats up, its resonant frequency may increase. Specifically, the current resonant frequency measurement of the blade may increase (e.g., slightly) relative to the previously measured resonant frequency. In one aspect, the main hysteresis loop 50 may reflect this increase, such as in curve 51. Conversely, if a subsequent resonant frequency measurement is less than the previous measurement, the change in resonant frequency is decreased (or reduced), which corresponds to a change in the direction of curve 52. max From Tmin This is reflected in the move to

[0060] As described herein, the hysteresis loop 50 shows the temperature behavior of the end effector with respect to changes in resonant frequency as the end effector heats up from a minimum temperature to its maximum temperature and then back to its minimum temperature again. This behavior may occur during use of an ultrasonic instrument. For example, an operator may start up an ultrasonic instrument by operating (beginning to operate) the instrument in a high power state to heat the end effector to its maximum temperature to perform a task. Once the task is completed, the instrument may be switched to a low power state, allowing the end effector to cool down to its minimum temperature (e.g., by entering a cooling cycle). However, in some cases, the operator may wish to continue using the ultrasonic instrument while it is cooling down (e.g., the current temperature of the end effector is along the main decreasing temperature curve 52, but the T min The operator may restart the ultrasonic instrument before the instrument reaches T. max The ultrasonic instrument may choose to switch the instrument to a low power mode before reaching temperature 0.5 V. As a result, the end effector may follow one or more different temperature curves contained within a hysteresis loop based on when the ultrasonic instrument switches between heating and cooling cycles.

[0061] 6, which shows a graphical representation of a hysteresis loop including several inner temperature curves, according to one embodiment. Specifically, the figure shows several inner temperature curves of the temperature model 45, which represent the temperature behavior of the end effector as the ultrasonic instrument switches between heating and cooling cycles (e.g., between high and low power states). For example, there are two inner decreasing temperature curves 61a and 61b, and two inner increasing temperature curves 62a and 62b, each of which represents the temperature behavior (e.g., having one or more temperature values) of the ultrasonic instrument relative to the change in resonant frequency as the end effector of the instrument cools and heats, respectively.

[0062] As shown, each of the inner decreasing temperature curves 61a and 61b starts at a different change in resonant frequency and decreases with respect to the change in resonant frequency (e.g., T min The inner curve 61a is ΔRFstart Cool(a) and the inner curve 61b is ΔRFstart Cool(b) This is the ΔRFstart Cool(a) In one aspect, each of these inner decreasing temperature curves represents the temperature behavior of the end effector as the ultrasonic instrument switches from a heating cycle (e.g., the temperature of the end effector follows curve 51) to a cooling cycle. Each of the inner increasing temperature curves 62a and 62b starts at a different change in resonant frequency and increases with respect to the change in resonant frequency (e.g., T max The inner curve 62a is ΔRFstart Heat(a) and the inner curve 62b is ΔRFstart Heat(b) This starts with ΔRFstart Heat(a) Thus, each of the inner increasing temperature curves represents the temperature behavior of the end effector as the ultrasonic instrument switches from a cooling cycle (e.g., the temperature of the end effector follows curve 52) to a heating cycle.

[0063] In one aspect, the temperature model 45 may include more or fewer inner curves, each of which has a different (or the same) starting change in resonant frequency. As shown, the starting resonant frequencies of the inner curves are aligned with the main hysteresis loop 50. In another aspect, the starting resonant frequencies of at least some of the inner (e.g., decreasing and / or increasing) curves may be within the hysteresis loop due to the ultrasonic instrument cycling while tracking the inner curve. In some aspects, the model may include (at least some of) the curves of the hysteresis loop, such as in one or more tables that relate one or more temperatures to one or more changes in resonant frequency according to the (e.g., main and / or inner) curve. In another aspect, the model may be configured to output one or more temperature values ​​based on one or more changes in resonant frequency. In that case, the temperature values ​​output by the model may be based on (or track) one or more of the (main and / or inner) curves described herein. Further discussion of using a model to determine the temperature of an end effector is provided herein.

[0064] Referring now to FIG. 7, this figure is a flow diagram of a process 70 for estimating the temperature of an ultrasonic instrument end effector while the instrument is being used by an operator of the surgical system 1. Notably, at least some of these operations may be performed once and / or while the ultrasonic instrument is in any of one or more power states described herein. For example, the surgical system may perform one or more of the operations of this process while the ultrasonic instrument is receiving power from the surgical system 1 (e.g., its generator 25). In one aspect, the process may be performed once or more while the instrument is receiving power to continuously estimate (e.g., in real time) the temperature of the instrument end effector. Thus, the temperature of the instrument blade may be estimated during (and / or between) heating and / or cooling cycles of the instrument based on the power state of the instrument. In one aspect, the process may be performed by one or more components of the surgical system 1, such as by the controller 40. As another example, at least some of the operations may be performed by the generator 25 (e.g., by its one or more processors). Therefore, this figure will be explained with reference to FIGS.

[0065] The process 70 begins by the controller 40 determining a change in the resonant frequency of the end effector 23 (e.g., the blade of the end effector 23) while the ultrasonic instrument is in either 1) a high power state in which the ultrasonic instrument draws a first current causing heat in the end effector, or 2) a low power state in which the ultrasonic instrument draws a second current less than the first current and not causing heat in the end effector (block 71). In particular, the controller 40 may receive (e.g., from the generator 25) one or more resonant frequency measurements of the ultrasonic instrument. The controller may then determine the change based on a comparison between the (e.g., currently) determined resonant frequency of the instrument and a previously determined resonant frequency (e.g., a resonant frequency measured immediately prior to the currently determined frequency). For example, the change may be the difference between the current resonant frequency and the previous resonant frequency. In this case, the change in resonant frequency may increase when the difference is positive and, conversely, decrease when the difference is negative. In another aspect, the change may be based on a comparison of two or more determined resonant frequencies.

[0066] In another aspect, the change in resonant frequency may be based on a determined starting resonant frequency (e.g., from generator 25). As described herein, the surgical system may be configured to use one or more (e.g., different) ultrasonic instruments (e.g., having one or more different types of components, such as different blades). Each ultrasonic instrument may have a slightly different starting resonant frequency due to slight variations (e.g., may be due to variations in manufacturing). As a result, each ultrasonic instrument may have a different starting resonant frequency that may be determined by the surgical system when the instrument is first turned on. For example, the system may determine a starting resonant frequency when the instrument is first powered on and operating in a low power state and while the instrument (e.g., blade) is cold and not being used. The controller 40 may be configured to determine the change in resonant frequency from this starting resonant frequency. In some aspects, the starting resonant frequency may be determined each time the surgical system (e.g., the ultrasonic instrument) is activated for a surgical procedure.

[0067] The controller 40 determines (at block 72) the temperature of the end effector by applying the change in resonant frequency to a hysteresis model (e.g., model 45 of FIG. 4) that includes a hysteresis relationship between the change in resonant frequency of the end effector and the corresponding temperature of the end effector. For example, the controller may retrieve the model 45 from the storage 44 of the surgical system 1, apply the change in resonant frequency, and receive the temperature of the end effector as an output. In some embodiments, the controller may determine the temperature (e.g., in real time) using a hysteresis model, such as a discretized Preisach model, as described herein. For example, application of the change in resonant frequency may adjust the hysteresis in the model, thereby determining the (e.g., current) temperature of the end effector. Further discussion of the use of the Preisach model is provided herein.

[0068] As described herein, the model may include a hysteresis loop (e.g., main loop 50) and one or more inner curves. In one aspect, the temperature may be determined based on these curves. For example, the controller may use one or more of the curves of the model to identify a temperature associated with a change in resonant frequency. For example, when the change in resonant frequency increases (which may be due to the ultrasonic instrument being in a high power state), the controller may use the main increasing temperature curve 51 to identify a temperature (on the curve) that corresponds to the change in resonant frequency. Conversely, when the change in resonant frequency decreases (e.g., while the ultrasonic instrument is in a low power state), the controller may use the main decreasing temperature curve 52 to identify a temperature (on the curve) that corresponds to the change in resonant frequency. In another aspect, the model may include one or more tables (e.g., the curves may be stored in one or more tables) from which the controller determines the temperature. For example, the temperature may be determined by performing a table lookup into a table that associates a change in resonant frequency with one or more temperature values ​​of the end effector.

[0069] The controller outputs a notification based on the temperature (block 73). For example, the controller may display a notification (e.g., a pop-up) on the display 15 of the surgical system 1 that includes the temperature of the end effector. In that case, the displayed notification may be a graphical user interface (GUI) item that is overlaid on a video and / or image being displayed on the display, such as an endoscopic video that may be provided by an endoscopic camera having a view of the surgical site (e.g., within the patient's abdomen). In another aspect, the notification may indicate the status of the end effector (e.g., "high" or "low"). In another aspect, the system may output an audible notification via the speaker 43. For example, the audible notification may be one or more sounds (e.g., beeps) that indicate that the end effector has a temperature above a threshold. Once the end effector has cooled below the threshold (or T min or another threshold is reached), the system may cease outputting the sound. In another aspect, the audible notification may be spoken (e.g., "Caution! Blade is hot!"). In another aspect, any type of notification may be used.

[0070] In one aspect, the controller may perform one or more of these operations in real-time (e.g., while the ultrasonic instrument is being used by the operator), such that the surgical system 1 may estimate (e.g., continuously) and provide (e.g., provide notification thereof) to the operator the temperature. In this case, the controller may continue to display the temperature of the end effector while the ultrasonic instrument is in a high power and / or low power state. In some aspects, the system may cease providing the notification upon determining that the temperature of the end effector has reached a threshold, as described herein. For example, the controller may determine whether the temperature is below a temperature threshold. In response to determining that the temperature is above the threshold, the controller may output (e.g., continue to output) the notification. However, if the temperature is below the threshold, the controller may cease outputting the notification, which may provide an indication to the operator that the end effector is no longer hot. In another aspect, the controller may output a notification that the end effector is no longer hot (e.g., by displaying a pop-up notification on the display, such as "Blade is cold").

[0071] In some aspects, the controller may be configured to determine when the temperature of the end effector will fall below a temperature threshold. For example, as described herein, the controller determines the temperature of the end effector based on a change in resonant frequency. The controller may then use the model to estimate when the blade will fall below a temperature threshold based on a rate of change of temperature with respect to time. For example, the model 45 may determine when the curve of the hysteresis loop will change from its starting change in resonant frequency to T max Or T min The time period (or rate of change) it takes for the end effector to reach a temperature (e.g., T ). Thus, the controller may determine the time based on the rate of change of the model. Once determined, the controller can determine when the end effector will become cold or hot (e.g., T max The notification may be configured to include a time to provide an indication to the operator regarding the time it takes to reach that threshold temperature (time to reach 100° C.) or another threshold temperature.

[0072] Some embodiments may implement one or more variations of the process 70 described herein. For example, certain operations of the process may not be performed in the exact order shown and described. Certain operations may not be performed in one continuous series of operations, and different certain operations may be performed in different embodiments.

[0073] As described herein, the surgical system 1 is configured to determine the temperature of the end effector based on one or more changes in resonant frequency. Thus, the system determines the temperature using one or more signal processing operations (e.g., by applying the change in resonant frequency to a temperature model, as described herein) without using temperature data from a temperature sensor. In some embodiments, the system may not include a temperature sensor (e.g., an infrared temperature sensor such as a thermocouple, etc.).

[0074] FIG. 8 is a flow diagram of a process 80 for determining the temperature of an ultrasonic instrument using a hysteresis model. Specifically, at least some of the operations described in this process may be performed in block 72 of process 70 of FIG. 7 to determine the temperature of the end effector using the hysteresis model 45 described in FIG. 4. In one aspect, the operations may be performed by the surgical system 1 (e.g., the generator 25 and / or the controller 40). The process 80 begins by the controller determining a resonant frequency of the end effector while the ultrasonic instrument is being used by an operator during a surgical procedure (block 81). In one aspect, the resonant frequency may be received by the generator 25 while the ultrasonic instrument is in any of the power states described herein (e.g., high power or low power). The controller determines a change in the resonant frequency based on a difference between the determined resonant frequency and a previously determined resonant frequency (block 82). In one aspect, the change may be a positive value indicating that the change is increasing, and conversely, if the change is a negative value, this may indicate that the change is decreasing. This can be illustrated in FIG. 5, where if the change is a positive value, the change in resonant frequency will be shifted in the positive x-direction (from a previously determined change in resonant frequency) by the amount of the change.

[0075] The controller 40 determines whether the change in resonant frequency is increasing (decision block 83). In one embodiment, this may be determined based on whether the change is a positive value. If so, the controller turns on a hysteron having an α less than the determined resonant frequency (block 84). In one embodiment, a hysteron that is turned on provides a positive weighting coefficient value (e.g., +μ) to the end effector temperature output. The controller determines the temperature of the end effector by summing the weighted coefficients according to the hysterons (block 86). Specifically, the temperature is determined by summing all the weighting coefficients coming from all the hysterons.

[0076] If the change is a decrease rather than an increase, the controller turns off the hysterones that have a β greater than the determined resonant frequency (block 85). Specifically, the change may be decreasing if the change (the difference between the currently determined resonant frequency and the previously determined frequency) is a negative value. In this case, the hysterones that are turned off give the output a negative weighting coefficient value (e.g., -μ). In one embodiment, the decision of which hysterones to turn on (and / or off) may be based on the change in resonant frequency. For example, when the change is decreasing, the controller may turn off the hysterones that have a β greater than the determined change in resonant frequency. The controller then determines the temperature by summing the coefficients of all the hysterones at block 86, as described herein.

[0077] In one aspect, the determined temperature may be increased or decreased (from a previously determined current temperature of the end effector) based on whether the change is increasing or decreasing. For example, if the change in resonant frequency is a positive value, the determined temperature may be a first temperature, and if the change in resonant frequency is a negative value, the determined temperature may be a second temperature that is lower than the first temperature. In particular, the first temperature may be higher than the previously determined temperature, while the second temperature may be lower than the previously determined temperature.

[0078] The controller determines whether the ultrasonic instrument is still being used (block 87). For example, the controller may determine whether the ultrasonic instrument is in one of the powered states or whether the ultrasonic instrument is stopped (e.g., the generator is turned off). If the ultrasonic instrument is in a powered state, the controller may return to block 81 to determine the temperature of the end effector. Thus, the controller may continuously determine the temperature while the ultrasonic instrument is being used.

[0079] Some embodiments perform one or more variations of the process 80 described herein. For example, certain operations of the process may not be performed in the exact order shown and described. Certain operations may not be performed in one continuous series of operations, and different certain operations may be performed in different embodiments. As described herein, the process may turn the hysteron on / off based on whether the change in resonant frequency is increasing or decreasing, respectively. In one embodiment, if the change is equal to (or approximately) zero, this means that the resonant frequency has not changed, and the controller may determine that the temperature has not changed from a previous determination.

[0080] 9 shows a graphical representation of temperatures determined while an ultrasonic instrument is in use, according to one embodiment. Specifically, the figure shows the temperature behavior of an ultrasonic instrument due to changes in the resonant frequency of the end effector during use. In one embodiment, the temperature of the illustrated curve can be determined (e.g., in real time) using a hysteresis model according to each change in resonant frequency.

[0081] ΔRFstart Heat0 At this point, the temperature of the end effector is T min , which may be a result of the ultrasonic instrument entering a high power state. The temperature of the end effector follows a main increasing temperature curve 51, which may be due to an increasing change in resonant frequency. Cool1 At ΔRFstart , the temperature of the end effector begins to cool. In particular, at this point, the change in resonant frequency may begin to decrease (e.g., a first negative value), which may be due to the ultrasonic instrument entering a low power state. In one embodiment, the inner decreasing temperature curve 61b represents the time when the ultrasonic instrument reaches a low power state at ΔRFstart . Cool1 As it cools from ΔRFstart Heat2 At T, the temperature of the end effector may begin to heat up, which may be due to the ultrasonic instrument re-entering a high power state. max When ΔRFstart is reached, Heat2, one may follow the inner increasing temperature curve 62b associated with

[0082] FIG. 10 illustrates several stages of a display of a surgical system showing actions taken by an end effector of an ultrasonic instrument and showing notifications based on a determined temperature of the end effector. Specifically, each of the three stages 100-102 illustrates a display 15 of a surgical system 1 displaying an endoscopic video 103. The video may be provided by one or more endoscopic cameras of the system and shows a surgical site within a patient where a surgical procedure is being performed. In particular, the video 103 shows tissue 104 (e.g., a blood vessel) being manipulated by the end effector 23. In another aspect, the display may show other content, such as other video content and / or a graphical user interface (GUI) of the surgical system displaying one or more UI items.

[0083] The first stage 100 shows the end effector 23 grasping (a portion of) tissue 104. In particular, the grasper is positioned such that the tissue is disposed between the hinged arm 31 and the blade 30, and the hinged arm is moved toward the blade 30 such that the tissue is sandwiched (e.g., in contact) between both arms. In addition, the ultrasonic instrument of the end effector is being used to perform an ultrasonic instrument action on the tissue. In particular, the ultrasonic instrument may be in a high power state in which it is vibrating while the end effector is in contact with the tissue 104, thereby generating frictional heat to cut and seal the tissue.

[0084] This first stage also shows a notification 105 being output by the surgical system. Specifically, the notification is displayed as a GUI item overlaid on top of the endoscopic video 103. In particular, the notification includes the text "END EFFECTOR IS HOTT" to alert the operator to the temperature condition of the end effector. In another aspect, the notification may exist separate from the (e.g., other) video and / or images displayed on the display 15. In one aspect, the notification may be output based on the controller determining the temperature of the end effector, as described herein. In some aspects, the notification may be presented when the temperature of the end effector reaches a threshold value.

[0085] The second stage 101 shows the result of cutting and sealing tissue with the end effector. As shown, the tissue has been cut into two pieces by the end effector and has also been cauterized. In addition, the grasper is now in an open position (hinged arm 31 has been moved away from blade 30). Once the tissue has been cut, the operator may no longer need to heat the end effector, and therefore the instrument may switch from a high power state to a low power state to enter a cooling cycle, as described herein. Thus, at this stage, the ultrasonic instrument may be provided with a current (e.g., by generator 25) below a current threshold that causes the instrument to generate (e.g., frictional) heat in the blade of the end effector (e.g., when in contact with an object such as tissue). In addition, at this stage, the (controller 40 of) the surgical system may be configured to estimate the temperature of the end effector based on a change in resonant frequency, which at this stage may decrease, as described herein. Specifically, since at this stage the end effector has just entered a cooling cycle, the blade may still be hot (or may be above the temperature threshold). In particular, the controller may be configured to compare the current temperature of the end effector to the temperature threshold. At this stage, the current temperature is above the threshold, and as a result, the notification 105 displayed on the display continues to indicate "END EFFECTOR HOT" to alert the operator that the end effector continues to have residual heat from the heating cycle.

[0086] A third stage 102 indicates that the notification 105 has changed from "end effector hot" to "end effector cold." Specifically, this stage indicates that after a period of time, the residual heat in the end effector has subsided such that its determined temperature (e.g., based on a change in resonant frequency) has dropped below a temperature threshold, as described herein.

[0087] As described herein, the surgical system 1 may be configured to estimate the temperature of the end effector while the ultrasonic instrument is in either a high power state (e.g., being actively used by an operator to cut and cauterize tissue) or a low power state (e.g., a state in which the ultrasonic instrument cools down after an operator uses the instrument to cut and cauterize tissue). In one aspect, the operator may switch between these two states one or more times during a surgical procedure. As soon as the operator switches from applying high power through the generator to a low power state, the end effector may begin to cool quickly (e.g., to body temperature, e.g., about 37° C.). When the operator switches back to the high power state, the end effector begins to heat up again. In some cases, the end effector may take some time to heat up back to the desired temperature. In one aspect, the controller may be configured to maintain the desired temperature of the end effector to reduce the amount of time between cooling and heating cycles.

[0088] As described herein, the display 15 is arranged to present the endoscopic video 103 and notifications 105. In one embodiment, the generator's display 24 may display the video and / or notifications. For example, the display 24 may present the endoscopic video and notifications, or may display notifications while the system's display 15 displays the endoscopic video.

[0089] 11 is a flow diagram of a process 110 for maintaining a desired temperature of an ultrasonic instrument (e.g., an end effector of an ultrasonic instrument). In particular, the controller maintains the desired temperature by controlling whether the ultrasonic instrument is in a high or low power state based on one or more changes in the resonant frequency of the end effector. In one aspect, the process may be performed automatically (e.g., without user intervention) such that the temperature of the end effector is maintained at (or within) a desired temperature range.

[0090] Process 110 begins by the controller 40 determining a change in resonant frequency of an end effector (e.g., blade) of an ultrasonic instrument while the instrument is being used by an operator during a surgical procedure (block 111). Specifically, the change in resonant frequency may be determined while the ultrasonic instrument is operating in one of the power states described herein. The controller determines the temperature of the end effector by applying the change in resonant frequency as an input to a hysteresis model (e.g., model 45) that generates temperature as an output (block 112). The controller determines a desired temperature range for the end effector (block 113). In one aspect, the desired temperature range may include one or more temperature values. For example, the temperature range may include one or more temperature values ​​(e.g., 300°C to 315°C). In another aspect, the temperature range may include all temperature values ​​above a particular temperature value. In that case, the temperature range may be a single temperature value (e.g., 300°C) above which the end effector is set to operate. In that case, the desired temperature range may be a particular user-desired (or user-defined) temperature. For example, an operator may desire a particular temperature to perform a surgical task on a particular portion of tissue. In another aspect, the desired temperature range may be determined from a user input via an input device (e.g., via a touch-sensitive display screen of an electronic device) communicatively coupled to the surgical system. In another aspect, the desired temperature range may be determined based on the patient's tissue on which the end effector of the ultrasonic instrument is to perform a surgical task. For example, the controller may receive an endoscopic video of the surgical site and perform an image recognition algorithm on the video to identify a portion of tissue within the site where a surgical task (e.g., cutting, etc.) is to be performed by the ultrasonic instrument. The controller may determine the desired temperature based on the identified portion of tissue. For example, fatty tissue may have a higher temperature range than thinner tissue due to the amount of extra heat that may be required to cut and cauterize fatty tissue.

[0091] The controller 40 maintains a desired temperature range of the end effector by switching between a high power state in which the ultrasonic instrument draws a first current, causing heat in the end effector, and a low power state in which the ultrasonic instrument draws a second current, less than the first current, that does not cause heat in the end effector, based on the determined temperature (block 114). Specifically, the controller maintains the temperature of the end effector within the desired range. This may be done by determining if the determined temperature of the end effector is within the temperature range (e.g., includes a boundary value). In response to determining that the determined temperature is higher than the desired temperature range (or value), the ultrasonic instrument is configured to operate in a low power state (e.g., the end effector is hot enough so that the end effector does not cause heat). Conversely, in response to the controller determining that the desired temperature is below the desired temperature range, the ultrasonic instrument is configured to operate in a high power state (e.g., cause heat).

[0092] In one aspect, the temperature of the end effector may be maintained at (or within) a desired temperature range while the ultrasonic instrument is being used by an operator. Specifically, the system may maintain the temperature while the operator is performing a surgical task with the instrument, such as cutting and / or cauterizing tissue.

[0093] In one aspect, the controller may perform at least some of these operations continuously (e.g., while the ultrasonic instrument is being used by the operator) to maintain a desired temperature range of the end effector. Thus, the operations performed by the controller functionally create a "software sensor" where the state of the ultrasonic instrument is controlled based on changes in resonant frequency rather than using temperature sensor data from a temperature sensor. As a result, the desired temperature range is determined and maintained (e.g., in a surgical system) without using (and / or having) a temperature sensor.

[0094] As described herein, the ultrasonic instrument 20 may be a laparoscopic instrument held and manipulated by an operator. In another embodiment, the instrument may be part of a surgical robotic arm. For example, the ultrasonic instrument may be coupled to the distal end of a robotic arm, such as arm 4 of FIG. 1, and movement and manipulation of the ultrasonic instrument may be performed via one or more user controls (e.g., UID, foot pedal, etc.) coupled to the surgical system. In some embodiments, the ultrasonic instrument may be coupled to the arm and controlled by the generator based on user input. For example, the generator may control the rotational position of the hinged arm 31 to open and close the grasper 23 based on user input via one or more user input devices, such as UID 14, communicatively coupled to the generator, as described herein. In another aspect, the generator may adjust the spatial position (e.g., in space) of the end effector based on user input (e.g., based on the position of the UID). In another aspect, the spatial and / or rotational position of the hinged arm may be controlled by the controller 40 (e.g., based on user input received by the controller).

[0095] 12 is a flow diagram of a process 120 for creating a hysteresis model (e.g., model 45 of FIG. 4) that defines a hysteresis relationship between temperature and changes in resonant frequency of an end effector of an ultrasonic instrument. In one aspect, this process (or at least some of the operations of this process) may be performed in a controlled environment. In that case, the model may be predefined as it is created and becomes part of a surgical system for use during a surgical procedure.

[0096] The process 120 begins by empirically determining a first set of temperature data with respect to the change in resonant frequency of the end effector (block 121). Specifically, the empirical data is determined for an end effector of an ultrasonic instrument configured to operate as described herein in either 1) a high power state in which the instrument draws power such that the end effector generates heat, or 2) a low power state in which the instrument draws less power such that the end effector does not generate heat. In one aspect, the temperature data may include temperature values ​​of the end effector with respect to the resonant frequency (e.g., change in resonant frequency) while the end effector is being heated and cooled. For example, when heating (and cooling) the end effector, the system may monitor the temperature of the end effector (e.g., using a temperature sensor) at one or more discretized levels of (change in) the resonant frequency of the end effector, which may be determined based on data from the generator 25. In one aspect, the controller ... max ) and then heat it to a minimum temperature (e.g., T min ), a main hysteresis loop (e.g., loop 50 in FIG. 5) may be obtained. In some embodiments, the controller may also obtain one or more inner decreasing (and / or increasing) temperature curves, each of which begins at a particular change in resonant frequency.

[0097] The controller uses the first set of temperature data to determine additional temperature data related to the change in resonant frequency of the end effector as a second set of temperature data (block 122). In particular, the controller determines (or identifies) missing sampling points based on available experimental data that could not or was not determined experimentally. In some aspects, the controller may use one or more methods to determine this additional temperature data. For example, the controller may be configured to perform an interpolation between at least two adjacent experimentally determined temperature curves. For example, the controller may use two data points (e.g., T maxIn particular, the controller may indicate the frequency change at the start of cooling for each of the adjacent curves by ΔRFstart1 and ΔRFstart2, and the frequency change for the interpolated cooling curve may be calculated by ΔRFstart x whereby ΔRFstart2<ΔRFstart x <ΔRFstart2. Then, for each discrete level of change in resonant frequency along the cooling curves F1 and F2, the corresponding blade temperature values ​​of the two curves T1 and T2 can be obtained from the experimental data. These temperature values ​​and the corresponding change in resonant frequency are used to calculate the interpolated curve T x The temperature value of the resonant frequency F x Regarding the change in , it can be obtained using the following formula:

[0098]

number

[0099] When adjacent curves exist in the experimental data, an interpolation technique may provide sufficient temperature data for the end effector to populate the required sampling points in the hysteresis model. However, in some aspects, when only a small number of curves are available (e.g., less than a curve threshold) (e.g., due to minimal experimental data obtained) and / or when the available experimental data does not span the full range of possible variations in resonant frequency and end effector blade, the controller may perform a polynomial fit technique to obtain (at least some of) the additional temperature data. This technique is described herein.

[0100] First, the controller can fit a polynomial / function to each (or at least some) of the experimentally available curves (e.g., model the end effector temperature as a function of the change in resonant frequency on the curves). For example, for 1...n curves, each curve can be fitted as a second order polynomial such as:

[0101]

number

[0102] As a result, temperature is a polynomial function of ΔRF. Thus, T=p(ΔRF), where p is a second order polynomial with input of ΔRF. In another embodiment, temperature can be another function (e.g., a third order polynomial). In one embodiment, each of the curves can be a decreasing curve and / or an increasing curve, as described herein. In one embodiment, each of the coefficients a, b, and c can be associated with a particular value of the change in resonant frequency at the beginning (start) of the corresponding curve. Specifically, if the curve is an inner decreasing curve, the coefficients can be associated and tied to values ​​at the start of the cooling cycle. In one embodiment, the controller can find a fit that best describes the change in one or more coefficients as a function of the corresponding start change in resonant frequency, which can be shown as follows:

[0103]

number

[0104] therefore, a=p a (ΔRFstart)=x a ΔRFstart+y a b=p b (ΔRFstart)=x b ΔRFstart+y b c=p n (ΔRFstart)=x c ΔRFstart+y c

[0105] In one aspect, once these correlations are identified based on experimentally available data, the controller uses the correlations to generate additional data to complete missing sampling points in the model. For a sampling point on a particular cooling curve, the resonant frequency ΔRFstartx With the onset of change in , the coefficients associated with fitting a particular cooling curve may be calculated as follows: a x =p a (ΔRFstart x ) b x =p b (ΔRFstart x ) c x =p c (ΔRFstart x )

[0106] The controller may use a fit function to calculate the end effector temperature at each discretized value of change in resonant frequency along the cooling curve as follows: T(ΔRF i )=p(ΔRFi)=a x ΔRF i 2 +b x ΔRF i +c x

[0107] As described herein, the controller may interpolate and / or calculate temperature values ​​using polynomial fitting techniques along the cooling curve. In another aspect, the controller may do either (or both) of these techniques to determine temperature data for a heating (or increasing) curve that may begin along the main decreasing temperature curve of the main hysteresis loop.

[0108] Returning to process 120, the controller uses the first and second sets of temperature data to generate a hysteresis model including a hysteresis relationship between the change in resonant frequency and the temperature of the end effector (block 123). In particular, the controller determines turn-on / off thresholds for each hysteron (α, β) and a weighting coefficient μ for each hysteron. For example, the controller discretizes the input domain (e.g., the change in resonant frequency), with each hysteron defined by one or more discrete levels. The controller determines the weight of each hysteron by forming a temperature table (e.g., a look-up table) using the temperature data (e.g., the first and second sets of temperature data). To do this, the controller may perform the following sequence: 1) increase the change in resonant frequency to α, 2) the controller may tabulate the corresponding end effector temperature, 3) the controller may decrease the change in resonant frequency by one level (e.g., by a threshold amount), 4) again the controller may tabulate the corresponding end effector temperature, 5) the controller may continue to decrease the change in resonant frequency and continue to tabulate the corresponding temperature values ​​until the change in resonant frequency is zero. In one aspect, the controller may repeat steps 1)-5) until α reaches the maximum possible resonant frequency change.

[0109] In one aspect, the resulting temperature table is used to calculate a weighting factor for each hysteron based on each cell's individual contribution to the output (e.g., end effector temperature). Defining the blade temperature corresponding to αi and βi tabulated in the i-th row and j-th column of the formed table as f(i,j), the corresponding weighting factor is calculated based on the following equation: μ(i,j)=f(i+1,j+1)+f(i,j)-f(i+1,j)-f(i,j+1)

[0110] In one embodiment, the diagonal elements of the table are i=j=k, and the weighting factors are calculated based on the following formula: μ(k,k)=f(k+1,k+1)-f(k+1,k)

[0111] In some aspects, the determined weighting factors may be stored in a table, with each cell in the table being the weight μ of an individual hysteron with a distinct turn-on α and turn-off level β. As a result, when a hysteresis model is used to determine the temperature of the end effector, the weighting factors may be determined by performing a table lookup into the table according to one or more hysterons of the model.

[0112] In one aspect, a method performed by a surgical system including an ultrasonic instrument having an end effector, the method including: experimentally determining a first set of temperature data related to a change in resonant frequency of an end effector of an ultrasonic instrument configured to operate in either 1) a high power state in which the end effector draws power to generate heat, or 2) a low power state in which the ultrasonic instrument draws less power and does not generate heat in the end effector; using the first set of temperature data to determine additional temperature data related to the change in resonant frequency of the end effector as a second set of temperature data; and using the first and second sets of temperature data to generate a hysteresis model including a hysteresis relationship between the change in resonant frequency of the end effector and temperature.

[0113] As previously explained, aspects of the present disclosure may be a non-transitory machine-readable medium (such as a microelectronic memory) having instructions stored thereon that program one or more data processing components (collectively referred to herein as a "processor") to (automatically) perform the ultrasonic instrument operations and / or temperature estimation and notification operations described herein. In other aspects, some of these operations may be performed by specific hardware components that include hardwired logic. These operations may alternatively be performed by any combination of programmed data processing components and fixed hardwired circuitry components.

[0114] While particular embodiments have been described and illustrated in the accompanying drawings, it is to be understood that such embodiments are merely illustrative of the broad disclosure and are not limiting of the broad disclosure, and since various other modifications may occur to those skilled in the art, the disclosure is not limited to the specific construction and arrangements shown and described. Thus, the description should be regarded as illustrative instead of restrictive.

[0115] In some aspects, the disclosure may include a style such as, for example, "at least one of [element A] and [element B]." This style may refer to one or more of the elements. For example, "at least one of A and B" may refer to "A," "B," or "A and B." Specifically, "at least one of A and B" may refer to "at least one of A and at least one of B," or "at least one of A or B." In some aspects, the disclosure may include a style such as, for example, "[element A], [element B], and / or [element C]." This style may refer to any of the elements or any combination thereof. For example, "A, B, and / or C" may refer to "A," "B," "C," "A and B," "A and C," "B and C," or "A, B, and C."

[0116] [Embodiment] (1) A method performed by a surgical system including an ultrasonic instrument having an end effector, the method comprising: determining a change in a resonant frequency of the end effector while the ultrasonic instrument is in either 1) a high power state in which the ultrasonic instrument draws a first current causing heating in the end effector, or 2) a low power state in which the ultrasonic instrument draws a second current less than the first current and which does not cause heating in the end effector; determining a temperature of the end effector by applying the change in resonant frequency to a hysteresis model that includes a hysteresis relationship between the change in resonant frequency of the end effector and a corresponding temperature of the end effector; and outputting a notification based on the temperature. (2) determining the temperature of the end effector, determining the temperature to be a first temperature when the change in resonant frequency is a positive value; 2. The method of claim 1, further comprising: determining the temperature to a second temperature lower than the first temperature when the change in resonant frequency is a negative value. (3) The method of embodiment 1, wherein the hysteresis model includes a hysteresis loop including a first temperature curve having a first plurality of temperatures versus a plurality of changes in resonant frequency, and a second temperature curve having a second plurality of temperatures versus the plurality of changes in resonant frequency, the second plurality of temperatures being different from the first plurality of temperatures. (4) The method of embodiment 3, wherein the temperature values ​​of the first plurality of temperature values ​​increase for an increasing change in the resonant frequency and the temperature values ​​of the second plurality of temperature values ​​decrease for a decreasing change in the resonant frequency. (5) the model further includes a set of inner decreasing temperature curves contained within the hysteresis loop, each of the set of inner decreasing temperature curves having a set of temperatures for a set of changes in resonant frequency; Determining the temperature of the end effector comprises: selecting an inner decreasing temperature curve from the set of inner decreasing temperature curves based on the change in resonant frequency being associated with a respective set of changes in resonant frequency; and identifying the temperature from a respective set of temperatures of the inner decreasing temperature curve that corresponds to the change in resonant frequency.

[0117] (6) the changes in resonant frequency are negative changes in resonant frequency, the set of temperatures are a first set of temperatures, the set of changes in resonant frequency are a first set of changes in resonant frequency, the model further includes a set of inner increasing temperature curves contained within the hysteresis loop, the set of inner increasing temperature curves each having a second set of temperatures for a second set of changes in resonant frequency, and the method further includes: Determining a positive change in resonant frequency; selecting an inner increasing temperature curve based on said positive changes in resonant frequency being associated with a respective second set of changes in resonant frequency; 6. The method of claim 5, further comprising identifying a temperature along the inner increasing temperature curve that corresponds to the positive change in resonant frequency above the temperature. (7) The method of embodiment 3, wherein each change in resonant frequency among the plurality of changes is associated with a respective temperature among the second plurality of temperatures and another respective temperature among the first plurality of temperatures that is higher than the respective temperature among the second plurality of temperatures. (8) determining the temperature using the first temperature curve to identify the temperature that corresponds to the change in resonant frequency while the ultrasonic instrument is in the high power state; 8. The method of claim 7, further comprising: while the ultrasonic instrument is in the low power state, using the second temperature curve to identify the temperature corresponding to the change in resonant frequency. (9) determining a desired temperature range for the end effector; 2. The method of claim 1, further comprising maintaining the temperature of the end effector within the desired temperature range by controlling whether the ultrasonic instrument is in the high power state or the low power state based on one or more changes in a resonant frequency of the end effector. (10) outputting the notification, displaying the temperature on a display of the surgical system; and 2. The method of claim 1, further comprising at least one of: driving a speaker with an audio signal comprising the temperature-related audible alert.

[0118] (11) A surgical system comprising: an ultrasonic instrument having an end effector; A processor; When executed by the processor, the surgical system includes: determining a change in resonant frequency of the end effector while the ultrasonic instrument is in either 1) a heating cycle or 2) a cooling cycle; determining a temperature of the end effector by applying the change in resonant frequency to a temperature model; and a memory having instructions for outputting a notification based on the temperature. (12) The instructions for determining the temperature of the end effector include: determining the temperature to be a first temperature when the change in resonant frequency is a positive value; 12. The system of claim 11, further comprising instructions for determining the temperature to be a second temperature lower than the first temperature when the change in resonant frequency is a negative value. (13) The system of embodiment 10, wherein the temperature model includes a hysteresis loop including a first temperature curve having a first plurality of temperatures for a plurality of changes in resonant frequency, and a second temperature curve having a second plurality of temperatures for the plurality of changes in resonant frequency that are different from the first plurality of temperatures. (14) The system of embodiment 13, wherein the temperature values ​​of the first plurality of temperature values ​​increase for an increasing change in the resonant frequency and the temperature values ​​of the second plurality of temperature values ​​decrease for a decreasing change in the resonant frequency. (15) The instructions for determining the temperature include: using the first temperature curve to identify the temperature that corresponds to the change in resonant frequency while the ultrasonic instrument is in the heating cycle; 14. The system of claim 13, further comprising instructions for using the second temperature curve to identify the temperature corresponding to the change in resonant frequency while the ultrasonic instrument is in the cooling cycle.

[0119] (16) The system of claim 11, wherein the end effector comprises a blade arranged to oscillate along a longitudinal axis of the end effector, the blade 1) oscillating through a first range of motion while the ultrasonic instrument is in the heating cycle, and 2) oscillating through a second range of motion less than the first range of motion while the ultrasonic instrument is in the cooling cycle. (17) The memory includes: determining a desired temperature range for the end effector; The system of embodiment 11, further comprising instructions for maintaining the temperature of the end effector within the desired temperature range by controlling whether the ultrasonic instrument is in the heating cycle or the cooling cycle based on one or more changes in the resonant frequency of the end effector. (18) The instruction for outputting the notification comprises: displaying the temperature on a display of the surgical system; and 12. The system of claim 11, further comprising at least one of: driving a speaker with an audio signal including an audible alert related to the temperature. (19) The system of embodiment 11, wherein the temperature of the end effector is determined using one or more signal processing operations without using temperature data from a temperature sensor. (20) A method performed by a surgical system including an ultrasonic instrument having a blade, the method comprising: determining a change in resonant frequency of the blade; determining a temperature of the blade by applying the change in resonant frequency as an input to a hysteresis model which produces the temperature as an output; and maintaining a desired temperature range of the blade based on the determined temperature by switching between a high power state in which the ultrasonic instrument draws a first current causing heat in the blade and a low power state in which the ultrasonic instrument draws a second current less than the first current and which does not cause heat in the blade.

Claims

1. A surgical system, An ultrasonic instrument having an end effector, Processor and When executed by the aforementioned processor, the surgical system, The ultrasonic device determines the change in the resonant frequency of the end effector while it is in either a 1) heating cycle or a 2) cooling cycle. The temperature of the end effector is determined by applying the aforementioned change in the resonant frequency to a hysteresis model that includes a hysteresis relationship between the change in the resonant frequency of the end effector and the corresponding temperature of the end effector. A surgical system comprising: a memory having instructions for outputting a notification based on the aforementioned temperature.

2. The instruction for determining the temperature of the end effector is: When the aforementioned change in the resonant frequency is a positive value, the temperature is determined to be the first temperature. The surgical system according to claim 1, comprising an instruction to determine the temperature to a second temperature lower than the first temperature when the change in the resonant frequency is a negative value.

3. The surgical system according to claim 1, wherein the hysteresis model includes a hysteresis loop comprising a first temperature curve having a first plurality of temperatures for a plurality of changes in resonant frequency, and a second temperature curve having a second plurality of temperatures different from the first plurality of temperatures for the plurality of changes in resonant frequency.

4. The surgical system according to claim 3, wherein one of the first plurality of temperatures increases in response to an increasing change in the resonant frequency, and one of the second plurality of temperatures decreases in response to a decreasing change in the resonant frequency.

5. The command for determining the temperature is: While the ultrasonic instrument is in the heating cycle, the first temperature curve is used to identify the temperature corresponding to the change in the resonant frequency. The surgical system according to claim 3, comprising instructions for using the second temperature curve to identify the temperature corresponding to the change in the resonant frequency while the ultrasonic instrument is in the cooling cycle.

6. The surgical system according to claim 1, wherein the end effector comprises a blade arranged to vibrate along the longitudinal axis of the end effector, the blade vibrating over a first range of motion while the ultrasonic instrument is in the heating cycle, and vibrating over a second range of motion smaller than the first range of motion while the ultrasonic instrument is in the cooling cycle.

7. The aforementioned memory is Determine the desired temperature range of the end effector, The surgical system according to claim 1, further comprising commands for maintaining the temperature of the end effector within the desired temperature range by controlling whether the ultrasonic instrument is in the heating cycle or the cooling cycle based on a change in one or more resonant frequencies of the end effector.

8. The command for outputting the aforementioned notification, Displaying the temperature on the display of the surgical system, and The surgical system according to claim 1, comprising at least one of the following: driving a speaker with an audio signal including an audible alert related to the temperature.

9. The surgical system according to claim 1, wherein the temperature of the end effector is determined using one or more signal processing operations without using temperature data from a temperature sensor.

10. A method performed by a surgical system including an ultrasonic instrument having an end effector, the method is The change in the resonant frequency of the end effector is determined while the ultrasonic device is in either a high-power state where it draws in a first current and generates heat in the end effector, or a low-power state where it draws in a second current smaller than the first current and does not generate heat in the end effector. The temperature of the end effector is determined by applying the change in the resonant frequency to a hysteresis model that includes a hysteresis relationship between the change in the resonant frequency of the end effector and the corresponding temperature of the end effector. A method including outputting a notification based on the aforementioned temperature.

11. Determining the temperature of the end effector is When the aforementioned change in the resonant frequency is a positive value, the temperature is determined to be the first temperature, The method according to claim 10, comprising determining the temperature to a second temperature lower than the first temperature when the change in the resonant frequency is a negative value.

12. The method according to claim 10, wherein the hysteresis model includes a hysteresis loop comprising a first temperature curve having a first plurality of temperatures for a plurality of changes in the resonant frequency, and a second temperature curve having a second plurality of temperatures different from the first plurality of temperatures for the plurality of changes in the resonant frequency.

13. The method according to claim 12, wherein one of the first plurality of temperatures increases in response to an increasing change in the resonant frequency, and one of the second plurality of temperatures decreases in response to a decreasing change in the resonant frequency.

14. The hysteresis model further includes a set of inner-decrease temperature curves contained within the hysteresis loop, each of which has a set of temperatures for a set of changes in the resonant frequency. Determining the temperature of the end effector is Based on the fact that the aforementioned change in the resonant frequency is associated with each set of changes in the resonant frequency, an inner decrease temperature curve is selected from the set of inner decrease temperature curves, The method according to claim 12, comprising identifying the temperature from each set of temperatures in the inner decreasing temperature curve corresponding to the change in the resonant frequency.

15. The change in the resonant frequency is a negative change in the resonant frequency, the set of temperatures is a first set of temperatures, the change in the resonant frequency is a first set of temperatures, the hysteresis model further includes a set of inner increasing temperature curves contained within the hysteresis loop, each of the set of inner increasing temperature curves having a second set of temperatures for a second set of changes in the resonant frequency, and the method is Determining the positive change in the resonant frequency, Based on the fact that the aforementioned positive change in the resonant frequency is associated with each second set of changes in the resonant frequency, the inner increasing temperature curve is selected, The method according to claim 14, further comprising identifying a temperature higher than the temperature along the inner increasing temperature curve corresponding to the positive change in the resonant frequency.

16. The method according to claim 12, wherein each change in the resonant frequency among the plurality of changes is associated with each of the second plurality of temperatures and each of the first plurality of temperatures that is higher than each of the second plurality of temperatures.

17. Determining the aforementioned temperature is While the ultrasonic device is in the high-power state, the first temperature curve is used to identify the temperature corresponding to the change in the resonant frequency, The method according to claim 16, comprising using the second temperature curve to identify the temperature corresponding to the change in the resonant frequency while the ultrasonic instrument is in the low-power state.

18. Determining the desired temperature range of the end effector, The method according to claim 10, further comprising: maintaining the temperature of the end effector within the desired temperature range by controlling whether the ultrasonic device is in the high-power state or the low-power state based on a change in one or more resonant frequencies of the end effector.

19. Outputting the aforementioned notification Displaying the temperature on the display of the surgical system, and The method according to claim 10, further comprising at least one of driving a speaker with an audio signal including an audible alert related to the temperature.

20. A method performed by a surgical system including an ultrasonic instrument having a blade, the method is To determine the change in the resonant frequency of the blade, The temperature of the blade is determined by applying the change in the resonant frequency as an input to a hysteresis model that generates the temperature as an output, A method comprising maintaining a desired temperature range of the blade by switching between a high-power state in which the ultrasonic device draws a first current to generate heat in the blade and a low-power state in which the ultrasonic device draws a second current that is smaller than the first current and does not generate heat in the blade, based on the determined temperature.

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