Method and system for model-based temperature estimation of ultrasonic instrument

Abstract

A method performed by a surgical system including an ultrasonic instrument having an end effector is disclosed. The method determines a change in a resonant frequency of the end effector when the ultrasonic instrument is in: 1) a high power state in which the ultrasonic instrument draws a first current to cause the end effector to generate heat; or 2) a low power state in which the ultrasound instrument draws a second current less than the first current that does not cause the end effector to generate heat. The method determines a temperature of the end effector by applying the change in resonant frequency to a hysteresis model, the 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 are generally directed to a surgical system that uses a temperature model to estimate the temperature of an ultrasonic instrument while the instrument is in use during a surgical procedure. Other aspects are also described. Background Art

[0002] Minimally invasive surgery (MIS), such as laparoscopic surgery, uses techniques designed to reduce tissue damage during surgical procedures. Laparoscopic procedures typically require making multiple small incisions in a patient's body (e.g., in the abdomen), through which several surgical tools (such as an endoscope, blades, graspers, and needles) are inserted. Gas is injected into the abdomen, inflating it and providing more space around the tips of the tools, making it easier for the surgeon to see (via the endoscope) and manipulate tissue at the surgical site. MIS can be performed faster and with less surgeon fatigue using a surgical robotic system in which surgical tools are operably attached to the distal ends of robotic arms, and a control system actuates the arms and their attached tools. When the surgeon manipulates a handheld user input device (UID), the tool's tip simulates its position and orientation movement. A surgical robotic system can have multiple surgical arms, one or more of which have an attached endoscope, and other 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, when a surgical tool is positioned at a surgical site on a patient, a tool driver having one or more motors may actuate one or more degrees of freedom of the surgical tool in response to user commands. Summary of the Invention

[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 tip may include a blade that reaches a high temperature (e.g., greater than 300°C) during a "heating" cycle in which the blade oscillates against the tissue mass, thereby generating heat during the oscillation due to friction between the blade and the tissue. After reaching the high temperature, the blade can be used to cut a portion of the tissue while also sealing the remaining tissue. By performing multiple tasks (e.g., cutting for dissection, cauterization, etc.), the use of tools during laparoscopic surgery reduces instrument changes and the number of instruments during the procedure.

[0005] An ultrasonic instrument can be repeatedly activated by the operator of a laparoscopic surgical system to perform various surgical tasks, such as cutting and / or sealing long tissues. After completing a sealing or cutting task, the instrument's blade can be deactivated and enter a "cooling cycle," where the blade begins to cool from the high temperature at which it was used to perform the surgical task. At the beginning of the cooling cycle, the blade may still be hot due to residual heat on the blade. This heat may require a certain period of time (e.g., a considerable period of time) to dissipate. Therefore, while the instrument is in the cooling cycle, the operator must be careful to avoid contact with remaining tissue to prevent inadvertent thermal damage to potentially sensitive tissue. However, there is currently no mechanism to inform the operator of the blade temperature, and therefore they must rely on their experience to guess when the blade has cooled sufficiently to continue manipulating other tissues without causing thermal damage. With repeated activation / deactivation (e.g., repeatedly switching between heating and cooling cycles) to perform different types of surgical tasks (e.g., longer / shorter sealing and / or cutting), it becomes even more challenging for the operator to manually determine (or estimate) the blade temperature and when the blade has sufficiently cooled. Therefore, there is a need to estimate (or determine) the temperature information of the ultrasonic instrument 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 the resonant frequency of an end effector while the ultrasonic instrument is in one of the following states: a "high power" state (e.g., a heating cycle), in which the ultrasonic instrument draws a first current that causes the end effector to generate heat; or 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 the end effector to generate heat. The system determines the end effector temperature 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 end effector (e.g., including a blade) of the ultrasonic instrument and the corresponding temperature of the end effector. In one aspect, the model may have been previously defined in a controlled environment (e.g., in a laboratory). In some aspects, when a change in frequency is input into the model, the temperature of the model may be output. The system outputs a notification based on the temperature. For example, the system may display (e.g., as a pop-up) a notification that includes the temperature.

[0007] In one aspect, the hysteresis model includes one or more hysteresis loops, each having a first temperature profile having a first set of temperatures for a number of changes relative to the resonant frequency, and a second temperature profile having a second set of temperatures for a number of changes relative to the resonant frequency. Specifically, each hysteresis loop includes two (e.g., different) temperatures for a change in the resonant frequency. For example, each change in the resonant frequency may be associated with a corresponding temperature from the second set and another corresponding temperature from the first set, the other corresponding temperature from the first set being greater than the corresponding temperature from the second set. This may be due to the first temperature profile being associated with increasing end effector temperature values ​​relative to an increasing change in the resonant frequency, and the second temperature profile being associated with decreasing end effector temperature values ​​relative to a decreasing change in the resonant frequency. In one aspect, when the ultrasonic instrument is in a high power state, the first temperature profile may be used to identify a temperature corresponding to a determined change in the resonant frequency, and when the ultrasonic instrument is in a low power state, the second temperature profile may be used to identify a temperature corresponding to a determined change in the resonant frequency.

[0008] In one aspect, the end effector may include a blade that vibrates along a longitudinal axis and may include an articulated arm rotatably coupled to a joint of the end effector about a transverse axis. In some aspects, 1) when the ultrasonic instrument is in a high power state, the blade vibrates (e.g., reciprocates back and forth) at a first excursion (e.g., the blade moves forward (or backward) a first distance from a starting position) to generate heat; and 2) when the ultrasonic instrument is in a low power state, the blade vibrates at a second excursion less than the first excursion below a frequency threshold.

[0009] In some aspects, the surgical system may perform one or more operations based on the determined temperature. For example, the system may determine a desired temperature range for the end effector and may maintain 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 (e.g., future) changes in the resonant frequency of the end effector. In another aspect, the system determines whether the temperature is less than a temperature threshold and, in response to determining that the temperature is less than the temperature threshold, stops outputting a notification. 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., reading "END EFFECTOR IS HOT!"). As another example, the notification may be an audible warning played by a speaker of the surgical system. Specifically, the surgical system may drive the speaker 43 with an audio signal including an audible warning related to the temperature (e.g., playing the currently determined temperature, etc.). Once the temperature drops below the threshold, this may indicate that the end effector has sufficiently cooled. Therefore, the system may stop outputting the notification, which 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 can be configured to perform closed-loop temperature control of an ultrasonic instrument. Specifically, the system determines a change in the 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 the temperature as an output. The system maintains a desired temperature range for the blade by switching between the following states based on the determined temperature: a high-power state, in which the ultrasonic instrument draws a first current that causes the blade to generate heat; and a low-power state, in which the ultrasonic instrument draws a second current that is less than the first current and does not cause the blade to generate heat.

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

[0012] In some aspects, the system receives an endoscopic video of a surgical site, performs an image identification algorithm on the endoscopic video to identify a tissue mass in the surgical site on which a surgical task is to be performed by an ultrasonic instrument, and determines a desired temperature range for a blade based on the tissue mass. In another aspect, the desired temperature range is maintained without a user temperature sensor.

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

[0014] The above summary does not constitute an exhaustive list of all aspects of the present disclosure. It is contemplated that the present disclosure includes all systems and methods that can be implemented by all suitable combinations of the various aspects summarized above, as well as those disclosed below in the detailed description and particularly pointed out in the claims. Such combinations may have particular advantages not specifically recited in the above summary. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Various aspects are illustrated by way of example and not limitation in the figures of the accompanying drawings, wherein like reference numerals indicate similar elements. It should be noted that references to "an" or "an" aspect of the present disclosure are not necessarily to the same aspect, and that they refer to at least one aspect. In addition, for the sake of brevity and to reduce the total number of figures, a given figure may be used to illustrate features of more than one aspect, and not all elements in a figure may be required for a given aspect.

[0016] Figure 1 A pictorial view of an exemplary surgical system in a surgical setting is shown.

[0017] Figure 2 A pictorial view of an ultrasonic instrument and generator is shown according to one aspect of the present disclosure.

[0018] Figure 3 Shown Figure 2 The end effector of the ultrasonic instrument.

[0019] Figure 4 is a block diagram of a surgical system according to one aspect.

[0020] Figure 5 Shown is a graphical representation of a hysteresis loop of a hysteresis model according to one aspect.

[0021] Figure 6 A graphical representation of a hysteresis loop including several internal temperature curves is shown according to one aspect.

[0022] Figure 7 is a flow chart of a process for estimating the temperature of an end effector of an ultrasonic instrument while an operator of a surgical system is using the instrument.

[0023] Figure 8 is a flow chart of a process for determining the temperature of an ultrasonic instrument using a hysteresis model.

[0024] Figure 9 Shown is a graphical representation of determined temperatures while using an ultrasonic instrument according to one aspect.

[0025] Figure 10Several stages of a display of a surgical system showing actions performed by an end effector of an ultrasonic instrument and showing notifications based on a determined temperature of the end effector are shown.

[0026] Figure 11 is a flow chart of a process for maintaining a desired temperature of an ultrasonic instrument.

[0027] Figure 12 is a flow chart of a process for creating a hysteresis model that defines a hysteresis relationship between temperature and changes in resonant frequency. DETAILED DESCRIPTION

[0028] Several aspects of the present disclosure will now be explained with reference to the accompanying drawings. Whenever the shapes, relative positions, and other aspects of the parts described in a given aspect are not expressly defined, the scope of the present disclosure is not limited to the parts shown, which are shown for illustrative purposes only. In addition, although many details are set forth, it should be understood that some aspects can be practiced without these details. In other cases, well-known circuits, structures, and technologies are not shown in detail to avoid obscuring the understanding of this specification. In addition, unless the meaning is clear to the contrary, all ranges listed herein are deemed to include the endpoints of each range.

[0029] Figure 1 A pictorial view of an exemplary surgical system (which may be referred to hereinafter as a "system") 1 in a surgical setting is shown. The system 1 includes a user console 2, a control tower 3, and one or more surgical robotic arms 4 at a surgical robotic operating table (surgical table or surgical platform) 5. In one aspect, the arms 4 may be mounted to a Figure 1 , or a combination thereof. The system 1 may include an operating table or bed on which the patient is positioned as shown in the example of . 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 on a ceiling, a side wall, or another suitable structural support (such as a cart separate from the operating table). The system 1 may incorporate any number of devices, tools, or accessories for performing surgery on the patient 6. For example, the system 1 may include one or more surgical tools (instruments) 7 for performing a surgical procedure. The surgical tool 7 may be an end effector attached to the distal end of the surgical arm 4 for performing the surgical procedure.

[0030] Each surgical tool 7 can be manually manipulated, robotically manipulated, or both during a surgical procedure. For example, a surgical tool 7 can be a tool for accessing, viewing, or manipulating the internal anatomical structures of a patient 6. In one aspect, the surgical tool 7 is a gripper that can grasp the patient's tissue. The surgical tool 7 can be manually controlled by a bedside operator 8; or it can be robotically controlled via actuation of a surgical robot arm 4 to which it is attached. For example, when manually controlled, the operator can (e.g., physically) hold a portion of the tool (e.g., a handle) and can 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 handle of the tool). On the other hand, when robotically controlled, the surgical system can manipulate the surgical tool based on user input (e.g., received via a user console 2, as described herein).

[0031] Generally, a remote operator 9 (such as a surgeon or other operator) can use the user console 2 to remotely manipulate the arm 4 and / or attached surgical tools 7, for example during a teleoperation. The user console 2 can be located in the same operating room as the rest of the system 1, such as in a conventional operating room. Figure 1 As shown. However, in other environments, the user console 2 may be located in an adjacent or nearby room, or it may be located in a remote location, for example, 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 controls (or foot pedals) 13, one or more (handheld) user input devices (UIDs) 14 and at least one display 15. The display is configured to display a view of a surgical site within a patient 6, for example. The display may be configured to display image data (e.g., still images and / or video). In one aspect, the display may be any type of display, such as a liquid crystal display (LCD), a light emitting diode (LED) display, an organic LED (OLED) display, etc. In some aspects, the display may be a 3D immersive display for displaying a 3D (surgical) presentation. For example, during a surgical procedure, one or more endoscopic cameras may capture image data of the surgical site, and the display presents the image data to the user in 3D. In one aspect, the 3D display may be an autostereoscopic display that provides a 3D perception to the user without the need for special glasses. As another example, the 3D display may be a stereoscopic display that provides 3D perception through the use of glasses (eg, via active shutters or polarization).

[0032] In another aspect, the display 15 can be configured to display at least one graphical user interface (GUI) that can provide information and / or interactive content to assist a user in performing surgical procedures using one or more instruments in the surgical system 1. For example, some of the displayed content can include image data captured by one or more endoscopic cameras, as described herein. In another aspect, the GUI can include selectable UI items that, when manipulated by a user, can cause the system to perform one or more operations. For example, the GUI can include UI items as interactive content to switch control between robotic arms. In one aspect, to interact with the GUI, the system can include an input device (such as a keyboard, mouse, etc.). In another aspect, the user can interact with the GUI using a UID 14. For example, the user can manipulate the UID to navigate through the GUI (e.g., using a cursor), and to make selections, the user can hover the cursor over a UI item and manipulate the UID (e.g., select a control or button). In some aspects, the display can be a touch-sensitive display. In this case, the user can make selections by navigating and selecting via the touch display. In some aspects, any method can be used to navigate and / or select UI items.

[0033] As shown, teleoperator 9 sits in chair 10 and views user display 15 while manipulating foot controls 13 and handheld UID 14 to remotely control one or more of arm 4 and surgical tool 7 (which is mounted on the distal end of arm 4).

[0034] In some variations, the bedside operator 8 can also operate the system 1 in an "in-bed" mode, wherein the bedside operator 8 (user) is now positioned to the side of the patient 6 and simultaneously manipulates the robotically driven tools (the end effector attached to the arm 4), e.g., holding the handheld UID 14 and the manual laparoscopic tools with one hand. For example, the bedside operator's left hand can manipulate the handheld UID to control the robotic components, while the bedside operator's right hand can manipulate the manual laparoscopic tools. Thus, in these variations, the bedside operator 8 can perform both robotic-assisted minimally invasive surgery and manual laparoscopic surgery on the patient 6.

[0035] During the exemplary procedure (surgical operation), the patient 6 is prepared for surgery and covered with a sterile drape in a sterile manner to achieve anesthesia. When the arms of the system 1 are in a stowed or withdrawn configuration, the initial access to the surgical site (to facilitate access to the surgical site) can be performed manually. Once access is completed, the initial positioning or preparation of the system 1 (including its arms 4) can be performed. Then, the surgical operation continues, wherein the remote operator 9 at the user console 2 utilizes the foot control 13 and the UID 14 to manipulate various end effectors and possible imaging systems to perform the surgical operation. Manual assistance can also be provided at the operating table or operating table by a bedside person (e.g., a bedside operator 8) wearing a sterile surgical gown. The bedside person can perform tasks on one or more of the robotic arms 4, such as retracting tissue, performing manual repositioning, and tool changes. Non-sterile personnel may also be present to assist the remote operator 9 at the user console 2. When the procedure or surgical procedure is complete, the system 1 and user console 2 may be configured or set to a state to facilitate completion of post-operative procedures, such as cleaning or disinfection, and entry or printing of healthcare records via the user console 2 .

[0036] 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) in the robotic system 1 for remote operation. The UID 14 can be communicatively coupled to the rest of the system 1, for example, via the console computer system 16 (or host). The UID 14 can generate spatial state signals corresponding to the movement of the UID 14, such as the position and orientation of the handheld housing of the UID, and the spatial state signals can be input signals that control the movement of the robotic arm actuators 17. The system 1 can use control signals derived from the spatial state signals to control the proportional movement of the actuators 17. In one aspect, the console processor of the console computer system 16 receives the spatial state signals and generates corresponding control signals. Based on these control signals that control how the actuators 17 are energized to drive the segments or connections of the arm 4, the movement of the corresponding surgical tool attached to the arm can simulate the movement of the UID 14. Similarly, interaction between the teleoperator 9 and the UID 14 may generate, for example, a grasp control signal that causes the jaws of the grasper of the surgical tool 7 to close and grasp tissue of the patient 6 .

[0037] System 1 may include several UIDs 14, with corresponding control signals generated for each UID controlling the actuators and surgical tools (end effectors) of a corresponding arm 4. For example, a teleoperator 9 may move a first UID 14 to control the movement of an actuator 17 located in the left robotic arm, where the actuator responds by moving a linkage, gear, etc. in 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 linkages, gears, etc. in system 1. System 1 may include a right arm 4 secured to a bed or table on the right side of a patient, and a left arm 4 located on the left side of the patient. Actuators 17 may include one or more motors controlled so that they drive rotation of a joint of arm 4 to, for example, change the orientation of an endoscope or gripper of a surgical tool 7 attached to the arm relative to the patient. The movement of several actuators 17 in the same arm 4 may be controlled by a spatial state signal generated from a particular UID 14. A UID 14 may also control the movement of a corresponding surgical tool gripper. For example, each UID 14 may generate a corresponding grasping signal to control the movement of an actuator (eg, a linear actuator) that opens or closes the jaws of a grasper at the distal end of the surgical tool 7 to grasp tissue within the patient 6 .

[0038] In some aspects, communication between the surgical robotic table 5 and the user console 2 can be through a control tower 3, which can translate user commands received from the user console 2 (and more specifically from the console computer system 16) into robotic control commands transmitted to the arm 4 on the surgical table 5. The control tower 3 can also transmit status and feedback from the surgical table 5 back to the user console 2. The communication connection between the surgical table 5, the user console 2, and the control tower 3 can be via a wired link (e.g., fiber optic) and / or a wireless link, using any suitable data communication protocol from a variety of wireless data communication protocols, such as Bluetooth. Any wired connection can optionally be built into the floor and / or walls or ceiling of the operating room. The system 1 can provide video output to one or more displays (including displays within the operating room and remote displays accessible via the Internet or other network). The video output or feed can also be encrypted to ensure privacy, and all or part of the video output can be saved to a server or electronic health record system.

[0039] Figure 2A pictorial view of an ultrasonic instrument 20 and a generator 25 according to one aspect of the present disclosure is shown. As shown, the ultrasonic instrument is a handheld laparoscopic tool that is configured to perform ultrasonic surgical procedures (e.g., cutting and sealing tissue) based on manual manipulation of the instrument by an operator (e.g., a surgeon) (e.g., manual manipulation of a handle 21). The ultrasonic instrument is coupled to (e.g., via a cable) the generator, which enables the ultrasonic instrument to operate in one or more power states, as described herein.

[0040] According to aspects of the subject technology, an ultrasonic instrument includes a handle (eg, including a tool driver) 21 , a cannula 22 , and an end effector 23 loaded into the cannula (eg, coupleable to a shaft of the instrument).

[0041] The handle 21 is arranged to be held by an operator and allows the operator to manipulate the ultrasonic instrument (e.g., the end effector 23 of the ultrasonic instrument) during a surgical procedure. In one embodiment, the handle 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 user input by pulling the trigger with one or more fingers while holding the handle. In one embodiment, the trigger may be arranged to manipulate the end effector (e.g., by adjusting Figure 3 ). In another embodiment, the handle may include one or more inputs for changing the power state of the instrument.

[0042] As described herein, the handle may include a tool driver arranged to drive the end effector 23 of the ultrasonic instrument. Specifically, the tool driver may include a (e.g., linear) motor or actuator arranged to vibrate (or oscillate) the end effector at one or more frequencies (e.g., at very high (ultrasonic) frequencies and at low frequencies). In some aspects, the tool driver is configured to vibrate the end effector so that a portion of the end effector (e.g., a blade) moves back and forth along one or more axes. Specifically, the tool driver may vibrate the end effector at one or more offsets, wherein at each offset, the end effector may be displaced at a different distance from a starting (or starting) position. More information about how the end effector vibrates is described herein. In another aspect, the tool driver may include an ultrasonic transducer configured to vibrate the end effector according to an input voltage / input current (e.g., applied by the generator 25).

[0043] As described so far, the ultrasonic instrument may include an end effector 23 and a tool driver 21. In one aspect, the ultrasonic instrument may be detachable from (and removably coupled to) the tool driver. In this case, the ultrasonic instrument as described herein may be an end effector that may be coupled to a handle (e.g., to the tool driver via a cannula of the handle). Specifically, the cannula may be coupled to the handle, wherein the cannula receives and guides the ultrasonic instrument (e.g., the shaft of the ultrasonic instrument) for coupling to the instrument. By being separate from the handle, this may allow multiple different tools to be coupled to the handle. In this case, the cannula 22 may receive and guide one or more surgical instruments (such as an endoscope, a stapler, etc.).

[0044] As described herein, the surgical system 1 includes an ultrasonic instrument 20 configured to generate heat based on vibrations of its end effector 23. In another embodiment, the instrument can be any type of energy (eg, laparoscopic) tool designed to generate heat.

[0045] As presently described, the ultrasonic instrument 20 can be a handheld laparoscopic instrument that can be manually held and manipulated by an operator. In another embodiment, the instrument can be part of a surgical robotic arm. Specifically, the ultrasonic instrument can be coupled to the robotic arm and powered by a generator, as described herein. For example, the ultrasonic instrument can be coupled to the distal end of the robotic arm (e.g., Figure 1 4 ), the robotic arm includes several components that allow the robotic arm to be controlled by an operator. For example, the surgical robotic arm 104 may include a plurality of connectors and a plurality of brake joint modules for actuating the plurality of connectors relative to each other. The joint modules may include various joint types, such as pitch joints or roll joints, which may substantially constrain movement of adjacent connectors about certain axes relative to other axes. The plurality of joint modules of the robotic arm 104 may be actuated to position and orient an ultrasonic instrument for robotic surgery. In one embodiment, the ultrasonic instrument may be coupled to the distal end via a tool driver arranged to actuate the end effector 23 of the instrument.

[0046] Where the ultrasonic instrument is coupled to the robotic arm, movement and operation of the ultrasonic instrument may be performed via one or more user controls coupled to the surgical system (e.g., a UID, a foot pedal, etc.). For example, the UID may be arranged to open / close the gripper 23 of the ultrasonic instrument and / or may be arranged to adjust the spatial position (in space) of the gripper based on user input (e.g., the position of the UID).

[0047] Steering Figure 3 , the figure shows Figure 2FIG. 1 illustrates an end effector 23 of an ultrasonic instrument. Specifically, the figure shows an end effector that is a gripper (or gripping device) received through a cannula 22 and includes a blade 30 (e.g., serving as a jaw) and an articulated arm (or jaw) 31 that is rotatably coupled to a joint (or robotic wrist) 32. Specifically, the blade is received (and extends) through the cannula and is arranged to be coupled to a tool driver (e.g., of the handle 21) such that the blade oscillates back and forth within the cannula. The articulated arm 31 is rotatably coupled to the cannula 22 (at the joint 32) and is arranged to rotate. The gripper is arranged to open and close based on the rotational position of the articulated arm relative to the blade (and / or cannula) about the rotational axis of the joint (e.g., the Z-axis). For example, the gripper is arranged to open (or be in an open position) when the articulated arm is rotated away from the blade (e.g., by a threshold distance). When in this position, the end effector can be oriented so that an object (such as tissue) can be disposed between the blade and the articulated arm (e.g., by moving the end effector around the object). When the articulated arm is rotated toward the blade (e.g., within a threshold distance), the gripper can be closed (or in a closed position) so that the gripper can grasp the object between the blade and the articulated arm. As described herein, the articulated arm can be arranged to apply pressure against the grasped object (e.g., to squeeze the object between the jaws) in order to grasp the object and / or perform dissection on the object.

[0048] As described herein, the blade 30 is the jaw of the gripper. Specifically, the blade is a jaw that is non-rotatable relative to the end effector (e.g., about the Z axis). The blade can be arranged to vibrate along the longitudinal axis of the blade (e.g., the Y axis) to generate heat when the ultrasonic instrument is in a high power state (or mode). Specifically, the blade can be driven (e.g., by a tool driver of the handle 21) to move back and forth (e.g., linearly) along the longitudinal axis of the end effector (and through the cannula, as described herein) to repeatedly shift the blade 30 at a certain (e.g., constant) frequency. Specifically, the blade can vibrate (e.g., reciprocate back and forth) on an offset (or displacement), wherein the blade moves a certain distance from a starting position (e.g., forward or away from the end effector) and then moves back that distance. In one aspect, the offset can be the distance the blade moves from the starting position to the extended position. In another aspect, the offset can be the distance the blade moves forward and backward.

[0049] As described herein, the blade can generate frictional heat when vibrated against an object. Specifically, when the gripper squeezes tissue between the two jaws, the blade can come into contact with the tissue and can vibrate against the tissue. As the blade vibrates, the end effector can cut and / or cauterize tissue, as described herein. In one aspect, the blade can vibrate differently (e.g., at different offsets) based on the power state of the ultrasonic instrument (e.g., how much power is being supplied to the ultrasonic instrument). More information about vibrating blades and the power state of ultrasonic instruments is described herein.

[0050] Return to Figure 2The generator 25 is configured to control the ultrasonic instrument 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 used by an operator (e.g., to manipulate tissue and / or perform one or more surgical tasks on tissue, such as cutting and sealing blood vessels and / or cutting, grasping, and dissecting tissue, during laparoscopic surgery). Specifically, the generator can provide power to the ultrasonic instrument so that the surgical system 1 (e.g., the ultrasonic instrument of the surgical system) can operate in one of one or more power states. For example, the generator can provide power to the instrument so 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 specific voltage) to cause the end effector 23 to generate heat. For example, the generator can provide (e.g., a first) current (or input current) to a handle of the ultrasonic instrument (e.g., a tool driver of the handle), which can use the current to drive the blade 30 to vibrate (or oscillate) at a (first) deflection (and at a specific frequency). When the blade of the end effector vibrates upward against an object (such as tissue) at this offset, frictional heat can be generated by the end effector, as described herein. In another aspect, the ultrasonic instrument can be configured to operate in a "low-power" state (or "cooling cycle"), wherein the ultrasonic instrument no longer draws (sufficient or as much) power from the generator, while the instrument is in a high-power state to heat the end effector. Specifically, when in this state, the generator can be configured to provide less power to the ultrasonic instrument than the power provided by the generator when the instrument is in the high-power state, such that the end effector does not generate heat (e.g., when in contact with an object). Specifically, the generator can provide a current (e.g., a second current) to the ultrasonic instrument that is less than the (first) current provided by the generator when the instrument is operating in the high-power state, and thus does not cause the end effector to generate heat (or as much heat as when the ultrasonic instrument is in the high-power state). Thus, once the ultrasonic instrument enters the low-power state from the high-power state, the ultrasonic instrument can begin to cool. Eventually, if maintained in the low-power state, the ultrasonic instrument will cool to (at least) a threshold temperature (e.g., room temperature). In one aspect, the second current can be less than a predefined threshold current. In one aspect, in the low power state, the blade can vibrate at the same frequency as in the high power state. In another aspect, the blade can vibrate within a tolerance frequency range.

[0051] Due to the lower current supplied to the instrument in the low-power state, the blade of the end effector can be driven differently by the tool driver 21 than when the instrument is in the high-power state. Specifically, the blade can vibrate at an offset different from the offset at which the blade vibrates when the instrument is in the high-power state. For example, when in the high-power state, the blade can vibrate at a first (e.g., high) offset, which can cause the blade to generate heat when pressed against an object, while when in the low-power state, the blade can vibrate at a second (lower) offset, which can be less than the first offset (e.g., the blade is displaced less along the longitudinal axis than in the first offset). In some aspects, the second offset can be less than a minimum threshold (e.g., if the blade were vibrating at the minimum threshold, it would generate heat at the minimum threshold). In one aspect, when vibrating at this lower offset and when vibrating upward against an object (such as a blood vessel), the end effector can generate no frictional heat. In one aspect, the resonant frequency is maintained within a tolerance range regardless of the power state in which the instrument is operated.

[0052] In one aspect, the difference in end effector vibration can be based on the amount of power drawn by the ultrasonic instrument when in different states. For example, the offset by which the blade displaces during oscillation can be based on (e.g., proportional to) the power drawn by the instrument, such that more power drawn by the instrument can cause the blade to vibrate at higher offsets. Conversely, when the ultrasonic instrument is in a low-power state, the instrument can draw less power, which causes the blade to vibrate less (compared to when the instrument is in the low-power state). Due to oscillating at a smaller displacement, the blade may not generate frictional heat (e.g., when in contact with tissue). In another aspect, the blade may generate some frictional heat when in the low-power state and in contact with an object, but this may be less than the heat generated when the instrument is in the high-power state. In this case, the generated frictional heat may not be sufficient to cut and / or seal tissue. In some aspects, due to operating in the low-power state, the end effector of the ultrasonic instrument can enter a cooling cycle, whereby heat generated by the end effector when the instrument is in the high-power state dissipates (e.g., over a certain period of time). On the other hand, the blade may not vibrate (eg, the tool driver 21 may not drive the blade) while in this low power state.

[0053] In one aspect, the system can enter (or operate in) at least one of the power states based on user input (e.g., received by the generator 25). Specifically, the generator can provide power to the ultrasonic instrument based on receiving user input into one or more input devices (e.g., input into a foot pedal, a user interface controlled by an operator and communicatively coupled to the system 1, and / or input at the handle 21 of the ultrasonic instrument). The power provided based on the user input can 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). For example, when the generator receives a (first) user input (e.g., by the operator pulling or pressing a trigger on the handle 21), the generator can provide current to the ultrasonic instrument (e.g., the tool driver 21 of the ultrasonic instrument), which uses the current to drive the end effector, as described herein. Thus, in the case where the trigger controls an articulated arm of the end effector, the generator is configured to provide current when the articulated arm is moved (e.g., moved at least a threshold distance toward the blade 30). In another aspect, the system may enter the low power state based on another (eg, second) user input (eg, receiving input from a different input device coupled to the generator, such as a foot pedal).

[0054] In some aspects, an ultrasonic instrument can be configured to switch between a high-power state and a low-power state. As described herein, the instrument can operate in the high-power state while the generator is receiving user input (e.g., a user pulling or pressing a trigger on a handle). The instrument can operate in the low-power state in response to the generator not receiving user input. For example, the ultrasonic instrument can switch from the high-power state to the low-power state in response to the user releasing the trigger on the handle (the generator can transition between these two states). In one aspect, the instrument can operate in the low-power state while the operator is not actively using the instrument to perform ultrasonic instrument operations, as described herein. Specifically, the system can enter the low-power state without receiving user input into 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 can switch back to the high-power state (e.g., in response to the user input). In another aspect, the instrument can operate in the low-power state in response to receiving user input (e.g., a user pressing a button on a user-input device). In another aspect, the instrument can operate in this state for a certain period of time. As described herein, the surgical system is configured to determine the temperature of the end effector while in a low-power state (e.g., after switching from a high-power state) in order to notify the operator of the temperature, which may be high due to the instrument having been operating in a high-power state. Once the end effector cools to a specific temperature (e.g., at or below a predefined temperature), the generator can deactivate the instrument by ceasing to provide a lower current, since at this temperature, the end effector is unlikely to cause thermal damage if it were to come into contact with tissue.

[0055] In one aspect, the generator can provide different levels of current to heat the blade, which can be based on user input. For example, the generator can receive a first user input (e.g., from a pedal coupled to the generator) and, in response, provide the maximum (allowable) amount of current to the ultrasonic instrument. The ultrasonic instrument can then drive the end effector at a maximum (e.g., predeterminable) deflection, which can cause the end effector to generate heat at a (first) high temperature. However, when the generator receives a second user input (e.g., from another pedal coupled to the generator), the generator can provide a lower amount of current to the ultrasonic instrument. As a result, the ultrasonic instrument can draw less power, causing the end effector to vibrate at a (second) lower deflection, which can be lower than the first deflection at which the blade vibrated in response to the first user input. However, this lower deflection can cause the end effector to heat at a lower temperature than the first temperature of the end effector when the ultrasonic instrument draws a higher current (in response to the generator receiving the first user input). By heating the end effector to different temperatures, different types of tissue can be cut and / or cauterized. For example, fattier tissue may require the end effector to be hotter (having a first temperature), while thinner (and less fat) tissue may require less heat (having a second temperature) in order to cut and / or cauterize the tissue. In another aspect, the generator can be configured to provide a current when in a high power state (e.g., to drive the end effector at a first, high deflection).

[0056] As described herein, an ultrasonic instrument can be activated (e.g., operated in a high-power state) based on whether the end effector is in a closed position to grasp an object (e.g., a tissue mass). For example, the ultrasonic instrument can be activated (e.g., by a user) so that the ultrasonic instrument can operate in a high-power state to draw sufficient current to cause the end effector to generate heat. Specifically, the generator can activate the ultrasonic instrument to close the end effector (e.g., to cause the articulated arm 31 to move within the distance of the blade 30) upon receiving user input. Once the user input is received to move the articulated arm, the generator can be configured to provide (e.g., sufficient) power to activate the instrument, as described herein. In some aspects, the generator can activate the instrument based on determining that the articulated arm and / or blade are in contact with an object. For example, the ultrasonic instrument can include one or more sensors (e.g., force sensors) that detect the presence of an object and / or detect contact between the two arms. Upon making this determination, the generator can provide a first current to oscillate the blade to cause the blade to generate heat.

[0057] In one aspect, a surgical system (e.g., a generator of the surgical system) can be configured to determine one or more characteristics of an ultrasonic instrument while the instrument is in one or more power states. For example, the generator can be configured to keep track of (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 can be configured to monitor at least some of these characteristics of the instrument when the instrument is operating in a high-power state. However, unlike conventional systems that are unable to determine characteristics when the ultrasonic instrument is in a cooling cycle because the instrument is deactivated (e.g., the generator is not providing power), the surgical system of the present disclosure is able to determine characteristics when the instrument is in a low-power state (or cooling cycle) because the instrument draws at least some power. For example, when in a low-power state, the generator can determine the resonant frequency of the end effector (e.g., the blade 30 of the end effector).

[0058] In one aspect, at least one of the characteristics of the ultrasonic instrument can be determined based on other characteristics. For example, one characteristic can be a change in the resonant frequency of (the blade of) the end effector. The generator can determine the change based on one or more (e.g., previously) monitored resonant frequencies. For example, the change in resonant frequency can 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 can be an average change over a period of time (or over several samples taken by the generator).

[0059] In one aspect, the surgical system can include additional components. For example, the system can include a cable connecting a generator to an ultrasonic instrument (e.g., an ultrasonic transducer configured to convert an electrical current drive signal into mechanical vibrations). In one aspect, the ultrasonic transducer can be connected to a waveguide that is connected to the blade 30 of the end effector 23.

[0060] As also shown, the generator 25 further includes a display 24 that is arranged to disclose information about the operation of the ultrasonic instrument. For example, the display may present temperature information, the current state of the ultrasonic instrument, and one or more characteristics described herein.

[0061] Figure 4 is a block diagram of a surgical system 1 according to one aspect. The system includes an ultrasonic instrument 20, a generator 25, a controller 40, a display 15, and a speaker 43 (which can be a standalone speaker or part of the system's electronics, such as a user console 2). In one aspect, the system can include more or fewer elements, such as having more than one display and / or no speaker.

[0062] In one aspect, the controller 40 can 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 a dedicated state machine). In one aspect, the controller can be part of an electronic device, such as the console computer system 16, the control tower 3, and / or the user console 2. Although shown as a single component, in one aspect, the controller can include one or more electronic components (e.g., a processor, memory, etc.) on a single electronic device (such as the console computer 16) or communicatively coupled across multiple devices (e.g., communicating over a wireless computer network). In some aspects, the controller can be part of a separate device, such as a remote server that communicates with one or more electronic devices. In another aspect, the controller can be part of (e.g., at least partially integrated into) the generator 25. In this case, at least some other components (e.g., a speaker and a display) can also be part of (integrated into) the generator. Thus, at least some of the operations performed by the controller described herein can be performed by the generator.

[0063] As described herein, a controller is configured to perform temperature estimation operations for the surgical system 1 to determine the (e.g., real-time) temperature of an ultrasonic instrument (e.g., an end effector of an ultrasonic instrument) while the instrument is being used by an operator of the system. Specifically, 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 being actively used by an operator to perform a surgical task). Specifically, the controller may be configured to apply the one or more characteristics to a temperature (e.g., hysteresis) model 45 stored in a memory (storage device) 44. Further information regarding the 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 the surgical system's memory (and / or stored in the controller's memory) 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).

[0064] As shown, the generator can receive user input (e.g., via one or more electronic devices coupled to the generator) for causing the generator to perform one or more operations. For example, user input can be received via an ultrasonic instrument (e.g., when a user pulls on a trigger on a handle) to cause the generator to provide current that causes the ultrasonic instrument to switch from a low-power state to a high-power state, as described herein.

[0065] The storage device (or memory) 44 stores a temperature model 45 for estimating (or determining) the temperature of the end effector 23 of the ultrasonic instrument based on one or more characteristics. In one aspect, the temperature model can be a predefined model in a controlled environment (e.g., a laboratory). More information about defining a model is described herein. In some aspects, the model can 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., the end effector 23 of the ultrasonic instrument). For example, the model can define the temperature (e.g., nonlinear behavior) of the instrument's end effector (e.g., the blade of the end effector) relative to one or more changes in a characteristic (e.g., a resonant frequency of the end effector (e.g., the blade of the end effector). For example, when the blade of the ultrasonic instrument heats during an activation (heating) cycle (e.g., when the instrument is in a high-power state), the material properties (e.g., stiffness) of the blade change, which is reflected by a change in the resonant frequency of the blade. When the blade enters a cool-down cycle (e.g., when in a low-power state) to cool (e.g., to room temperature), these changes in resonant frequency are reversed, although the resonant frequency does not follow the exact same rate and path as it did during the heating cycle. Thus, there is a hysteresis relationship between the blade's resonant frequency change and the blade's temperature. More information about this hysteresis relationship is described herein.

[0066] In one aspect, the hysteretic temperature model 45 can be any hysteretic model that defines the relationship between the resonant frequency and the temperature. For example, the model can be a hysteretic discretized Preisach model that models the output function as a weighted sum of separate relay functions (called hysterons). In one aspect, each hysteron (γ) has different on and off thresholds (e.g., α and β, respectively) and contributes a "+1" or "-1" value (when on and off, respectively) to the sum depending on the input value. In one aspect, the model can have a value that can be defined as γ α1β1 …γ αnβn In one aspect, each hysteron may be associated with a (eg, different) weight factor μ that defines the individual contribution of each hysteron to the total weight. Thus, hysteron (γ α1β1 …γ αnβn ) can be combined with the corresponding weight factor μ(μ α1β1 …μ αnβn). In some aspects, at least some of the hysterons can include different (or the same) on / off thresholds and / or weighting factors. The on / off thresholds can correspond to changes, such as an increase (or positive) or decrease (or negative) in the resonant frequency of the end effector, relative to the temperature model. In this case, the change in resonant frequency can be input to the model, which outputs the temperature of the end effector, which can be the sum of one or more hysterons (e.g., their weighting factors) of the hysteresis model. More information about using the model to determine the temperature of the end effector is described herein.

[0067] In some aspects, the hysteresis model 45 may include (or define) a hysteresis loop having temperature values ​​of the end effector of the ultrasonic instrument relative to changes in the resonant frequency of the end effector (e.g., when the instrument is in use). This is due to the hysteresis relationship between temperature and changes in resonant frequency, as described herein. Turning now to Figure 5 , which shows a graphical representation of a main hysteresis loop 50 of a model according to one aspect. 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 ​​relative to a (e.g., the same or similar) change in the resonant frequency of the end effector.

[0068] In one aspect, the hysteresis loop 50 represents the temperature behavior of the end effector when the ultrasonic instrument is in use. Specifically, the first temperature curve 51 represents several temperature values ​​of the end effector during a heating cycle from which the end effector is heated from a minimum temperature T, such as room temperature or a predefined temperature. min Start to end effector maximum temperature T max In some respects, T max This may be a predefined temperature, such as defined by the manufacturer's specifications for the end effector. As shown, the first curve 51 begins at a starting change in resonant frequency ΔRFstart during the heating cycle. Heat , where the temperature of the end effector is at (or close to) the minimum temperature T min In one aspect, ΔRFstart Heat ΔRFstart may represent a change in the resonant frequency of the end effector when the ultrasonic instrument enters a heating cycle (e.g., is activated) to perform a surgical task on a tissue mass (e.g., once the ultrasonic instrument is in a high power state). HeatThis may be a change in resonant frequency after a period of time from when the instrument is activated. As the change in the resonant frequency of the end effector increases (curve 51), the temperature value increases due to the increased heat generated by the end effector. Curve 51 represents the heating behavior of the end effector from a minimum temperature to a maximum temperature when the ultrasonic instrument is in a high power state (causing the end effector to generate heat). Therefore, the temperature value of curve 51 increases with the increase in resonant frequency.

[0069] The second temperature curve 52 represents the temperature at which the end effector is at T max When the end effector is cooled to the lowest temperature T min As shown, the second curve 52 starts at the starting change in resonant frequency ΔRFstart during the cooling cycle (or at the beginning of the cooling cycle). Cool , where the temperature of the end effector is at or near T max In one aspect, ΔRFstart Cool The second curve 52 may represent a change in the resonant frequency of the end effector once (or after a certain period of time) the ultrasonic instrument is no longer active and is in a low power state. For example, such a change may occur after receiving a user input to switch the end effector from a high power state to a low power state, thereby causing the end effector to begin a cooling cycle. As the change in the resonant frequency of the end effector decreases, the curve 52 (or the temperature value of the curve) decreases. The second curve 52 at T min Thus, the temperature values ​​of curve 52 decrease relative to the decreasing change in resonant frequency. In one aspect, 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.

[0070] In one aspect, this hysteresis between the change in resonant frequency and the end-effector temperature during heating and cooling cycles may be due to a delay caused by heat capacity accumulation and thermal gradients across the end-effector (e.g., its blade). Specifically, when the blade heats, the temperature of the entire structure increases rapidly, causing a shift in the resonant frequency. However, when cooling, although the blade temperature drops, the residual heat retained in the rest of the structure results in a slower recovery of the resonant frequency. Consequently, the two curves follow different temperature patterns, forming a hysteresis loop.

[0071] In one aspect, the change in resonant frequency can 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 can increase. Specifically, the current resonant frequency measurement of the blade can increase (e.g., slightly increase) relative to the previously measured resonant frequency. In one aspect, the main hysteresis loop 50 can reflect this increase, such as in curve 51. Conversely, if the subsequent resonant frequency measurement is less than the previous measurement, the change in resonant frequency is decreasing (or decreasing), which is reflected in the change from T max Move to T min In the direction of curve 52.

[0072] As described herein, the hysteresis loop 50 illustrates the behavior of the end effector's temperature relative to the change in resonant frequency as the end effector is heated from a minimum temperature to its maximum temperature and then back to its minimum temperature again. This behavior may occur during use of the ultrasonic instrument. For example, an operator may activate the ultrasonic instrument by operating the instrument (initially) 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 switch to a low power state, thereby allowing the end effector to cool (e.g., by entering a cooling cycle) to its minimum temperature. However, in some cases, the operator may reactivate the ultrasonic instrument while the ultrasonic instrument is cooling (e.g., when the current temperature of the end effector is not along the main decreasing temperature curve 52 but after reaching T min Instead, the operator may choose to max Thus, based on when the ultrasonic instrument switches between heating and cooling cycles, the end effector may follow one or more different temperature profiles contained within the hysteresis loop.

[0073] Steering Figure 6 , which shows a graphical representation of a hysteresis loop including several internal temperature curves according to one aspect. Specifically, the figure shows several internal temperature curves of a temperature model 45 that represent the temperature behavior of an end effector as the ultrasonic instrument switches between a heating cycle and a cooling cycle (e.g., between a high power state and a low power state). For example, there are two internal decreasing temperature curves 61a and 61b and two internal 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 changes in resonant frequency as the end effector of the instrument heats and cools, respectively.

[0074] As shown, each of the internal reduction temperature curves 61a and 61b starts at a different change in resonant frequency and decreases relative to the change in resonant frequency (eg, to or about T min ). The inner curve 61a starts at ΔRFstart Cool(a), and the inner curve 61b starts at ΔRFstart Cool(b) , which is greater than ΔRFstart Cool(a) In one aspect, each of these inner decreasing temperature curves represents the temperature behavior of the end effector when the ultrasonic instrument switches from a heating cycle (e.g., wherein the temperature of the end effector tracks 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 relative to the change in resonant frequency (e.g., to or about T max ). The inner curve 62a starts at ΔRFstart Heat(a) , and the inner curve 62b starts at ΔRFstart Heat(b) , which is greater than ΔRFstart Heat(a) Thus, each of the inner increasing temperature curves represents the temperature behavior of the end effector when the ultrasonic instrument switches from a cooling cycle (eg, where the temperature of the end effector tracks curve 52) to a heating cycle.

[0075] 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 along the main hysteresis loop 50. On the other hand, because the ultrasonic instrument switches cycles while tracking the inner curves, at least some of the starting resonant frequencies of at least some of the inner (e.g., decreasing and / or increasing) curves may be within the hysteresis loop. In some aspects, the model may include curves (at least some of them) of the hysteresis loop, such as in one or more tables that associate one or more temperatures with one or more changes in resonant frequency based on curves (e.g., main curve and / or inner curves). On the other hand, the model may be configured to output one or more temperature values ​​based on one or more changes in resonant frequency. In this case, the temperature value output by the model may be based on (or track) one or more of the (main and / or inner) curves described herein. More information about using the model to determine the temperature of the end effector is described herein.

[0076] Now turn Figure 7, which is a flow chart of a process 70 for estimating the temperature of an end effector of an ultrasonic instrument while an operator of a surgical system 1 is using the instrument. Specifically, 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, when the ultrasonic instrument receives power from the surgical system 1 (e.g., the generator 25 of the surgical system), the surgical system may perform one or more operations of the process. In one aspect, the process may be performed one or more times to continuously estimate the temperature of the end effector of the instrument (e.g., in real time) while the instrument receives power. Thus, the temperature of the blade of the instrument 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 one or more processors of the generator). Therefore, this figure will refer to Figures 4 to 6 Provide a description.

[0077] Process 70 begins with the controller 40 determining a change in the resonant frequency of the end effector 23 (e.g., the blade of the end effector) while the ultrasonic instrument is in: 1) a high-power state, in which the ultrasonic instrument draws a first current that causes the end effector to generate heat; or 2) a low-power state, in which the ultrasonic instrument draws a second current that is less than the first current and does not cause the end effector to generate heat (at block 71). Specifically, the controller 40 may receive one or more resonant frequency measurements of the ultrasonic instrument (e.g., from the generator 25). In this case, the controller may determine the change based on a comparison between a (e.g., currently) determined resonant frequency of the instrument and a previously determined resonant frequency (e.g., a resonant frequency measured immediately before the currently determined frequency). For example, the change may be the difference between the current and previous resonant frequencies. In this case, when the difference is positive, the change in resonant frequency may increase, and when the difference is negative, the change in resonant frequency may conversely decrease. In another aspect, the change may be based on a comparison of two or more determined resonant frequencies.

[0078] In another aspect, the change in resonant frequency can be based on a determined starting resonant frequency (e.g., from the generator 25). As described herein, a surgical system can 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). Due to minor differences (e.g., which may be due to manufacturing differences), each ultrasonic instrument can have a slightly different starting resonant frequency. Thus, each ultrasonic instrument can have a different starting resonant frequency, which can be determined by the surgical system when the instrument is first powered on. For example, the system can determine the starting resonant frequency when the instrument is first powered on and operating in a low-power state and when the instrument (e.g., blade) is cold and unused. The controller 40 can be configured to determine the change in resonant frequency based on the starting resonant frequency. In some aspects, the starting resonant frequency can be determined each time the surgical system (e.g., an ultrasonic instrument of the surgical system) is activated for a surgical procedure.

[0079] The controller 40 adjusts the resonant frequency by applying the change in resonant frequency to the hysteresis model (e.g., Figure 4 The controller may determine the temperature of the end effector using a hysteresis model 45 (e.g., a hysteresis model) that includes a hysteresis relationship between a change in the resonant frequency of the end effector and a corresponding temperature of the end effector (at block 72). For example, the controller may retrieve the model 45 from the storage device 44 of the surgical system 1, apply the change in resonant frequency, and receive as output the temperature of the end effector. In some aspects, the controller may determine the temperature (e.g., in real time) using a hysteresis model (e.g., a discretized Preisach model as described herein). For example, application of the change in resonant frequency may adjust the hysteron within the model, thereby determining the (e.g., current) temperature of the end effector. Further information regarding the use of the Preisach model is described herein.

[0080] As described herein, a model can include a hysteresis loop (e.g., a main loop 50) and one or more inner curves. In one aspect, a temperature can be determined based on these curves. For example, a controller can use one or more 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 can use a main increasing temperature curve 51 to identify a temperature (on the curve) corresponding to the change in resonant frequency. Conversely, when the change in resonant frequency decreases (e.g., when the ultrasonic instrument is in a low power state), the controller can use a main decreasing temperature curve 52 to identify a temperature (on the curve) corresponding to the change in resonant frequency. In another aspect, a model can include one or more tables (e.g., the curves can be stored in one or more tables) that the controller uses to determine the temperature. For example, the temperature can be determined by performing a table lookup in a table that associates the change in resonant frequency with one or more temperature values ​​of the end effector.

[0081] The controller outputs a notification based on the temperature (at box 73). For example, the controller may display a (e.g., pop-up) notification on the display 15 of the surgical system 1 that includes the temperature of the end effector. In this case, the displayed notification may be a graphical user interface (GUI) item overlaid on a video and / or image (such as an endoscopic video) being displayed on the display, which video and / or image may be provided by an endoscopic camera having a field of 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., "hot" or "cold"). 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) indicating that the end effector has a temperature above a threshold. Once the end effector has cooled below the threshold (or has reached another threshold, such as T min ), the system can stop outputting sounds. In another aspect, the audible notification can be spoken words (e.g., "Attention! The blade is hot!"). In another aspect, any type of notification can be used.

[0082] In one aspect, the controller may perform one or more of these operations in real time (e.g., while the operator is using the ultrasonic instrument), such that the surgical system 1 can (e.g., continuously) estimate the temperature and provide the temperature (e.g., a notification of the temperature) to the operator. In this case, the controller may continue to display the temperature of the end effector when the ultrasonic instrument is in a high-power and / or low-power state. In some aspects, the system may stop providing notifications 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 less than a temperature threshold. In response to determining that the temperature is above the threshold, the controller may (e.g., continue to) output notifications. However, if the temperature is less than the threshold, the controller may stop outputting notifications, 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").

[0083] In some aspects, the controller can 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. In this case, the controller can use a model to estimate when the blade will fall below the temperature threshold based on the rate of change of temperature with respect to time. For example, the model 45 can include a curve of a hysteresis loop from the initial change in its resonant frequency to the time when T max or T minThe time period (or rate of change) taken for the end effector to cool or heat (e.g., reaching T max time spent) or an indication of another threshold temperature.

[0084] Some aspects may perform one or more variations of the process 70 described herein. For example, specific operations of the process may not be performed in the exact order shown and described. Specific operations may not be performed in a series of consecutive operations, and different specific operations may be performed in different aspects.

[0085] 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 uses one or more signal processing operations to determine the temperature (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 aspects, the system may not include a temperature sensor (e.g., an infrared temperature sensor, such as a thermocouple, etc.).

[0086] Figure 8 is a flow chart 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 the process may be performed in Figure 7 The process 70 is executed in block 72 to use Figure 4 The hysteresis model 45 described in is used to determine the temperature of the end effector. In one aspect, the operations may be performed by the surgical system 1 (e.g., the generator 25 and / or the controller 40). Process 80 begins when an operator uses an ultrasonic instrument during a surgical procedure and the controller determines the resonant frequency of the end effector (at box 81). In one aspect, the resonant frequency may be received by the generator 25 when 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 (at box 82) based on the difference between the determined resonant frequency and a previously determined resonant frequency. In one aspect, the change may be a positive value, indicating that the change is increasing, conversely, if the change is a negative value, this may indicate that the change is decreasing. This may be in Figure 5 , where if the change is a positive value, the change in resonant frequency may be shifted in the positive x-direction (from the previously determined change in resonant frequency) by the amount of the change.

[0087] The controller 40 determines whether the change in resonant frequency is increasing (at decision block 83). In one aspect, this can be determined based on whether the change is positive. If so, the controller turns on a hysteron having an α less than the determined resonant frequency (at block 84). In one aspect, the turned-on hysteron contributes a positive weighting factor value (e.g., +μ) to the output of the end effector temperature. The controller determines the end effector temperature (at block 86) by summing the weighting factors according to the hysteron. Specifically, the temperature is determined by summing all weighting factors from all hysterons.

[0088] If the change is decreasing rather than increasing, the controller turns off the hysterons that have a β greater than the determined resonant frequency (at block 85). Specifically, when the change (the difference between the currently determined resonant frequency and the previously determined frequency) is negative, the change may be decreasing. In this case, the hysterons that are turned off contribute a negative weighting factor value (e.g., -μ) to the output. In one aspect, determining which hysterons 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 hysterons that have a β greater than the determined resonant frequency change. Then, as described herein, at block 86, the controller determines the temperature by summing the factors of all hysterons.

[0089] 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 an increase or decrease. For example, when the change in resonant frequency is positive, the determined temperature may be a first temperature, while when the change in resonant frequency is negative, the determined temperature may be a second temperature that is less than the first temperature. Specifically, the first temperature may be greater than the previously determined temperature, while the second temperature may be less than the previously determined temperature.

[0090] The controller determines whether the ultrasonic instrument is still in use (at block 87). For example, the controller can determine whether the ultrasonic instrument is in any power state or whether the ultrasonic instrument is deactivated (e.g., the generator is turned off). If the ultrasonic instrument is in a powered state, the controller can return to block 81 to determine the temperature of the end effector. Thus, the controller can continuously determine the temperature while the ultrasonic instrument is in use.

[0091] Some aspects implement one or more variations of process 80 described herein. For example, specific operations of the process may not be performed in the exact order shown and described. Certain operations may not be performed in a series of consecutive operations, and different specific operations may be performed in different aspects. 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 aspect, if the change is equal to (or approximately equal to) zero, meaning that the resonant frequency has not changed, the controller may determine that the temperature has not changed from a previous determination.

[0092] Figure 9 A graphical representation of determined temperatures during use of an ultrasonic instrument according to one aspect is shown. Specifically, the graph illustrates the temperature behavior of the ultrasonic instrument as a function of changes in the resonant frequency of the end effector during use. In one aspect, the temperature of the illustrated curve can be determined (e.g., in real time) using a hysteresis model based on corresponding changes in the resonant frequency.

[0093] In ΔRFstart Heat0 At this point, the temperature of the end effector begins to heat up to T min Above, this may be the 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 the change of the increase in resonant frequency. Cool1 At this point, the temperature of the end effector begins to cool. Specifically, 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 aspect, when the ultrasonic instrument is at ΔRFstart Cool1 When cooling, the internal temperature decreases as shown in curve 61b. Heat2 At this point, 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. When the temperature of the end effector reaches T max The temperature of the ultrasonic instrument can follow the ΔRFstart Heat2 The associated inner increasing temperature profile 62b.

[0094] Figure 10Several stages of a display of a surgical system are shown, the display showing actions performed by the end effector of an ultrasonic instrument and showing notifications based on the determined temperature of the end effector. Specifically, each of the three stages 100-102 shows the display 15 of the surgical system 1, which displays an endoscopic video 103. The video can be provided by one or more endoscopic cameras of the system, showing a surgical site within a patient on whom a surgical procedure is being performed. Specifically, the video 103 shows tissue 104 (e.g., a blood vessel) being manipulated by the end effector 23. In another aspect, the display can display other content, such as other video content and / or a graphical user interface (GUI) of the surgical system displaying one or more UI items.

[0095] The first stage 100 shows the end effector 23 grasping (a portion of) tissue 104. Specifically, the grasper has been positioned so that the tissue is disposed between the articulated arm 31 and the blade 30, and the articulated arm has been moved toward the blade 30 such that the tissue is sandwiched between (e.g., in contact with) the two arms. Furthermore, the ultrasonic instrument of the end effector is used to perform an ultrasonic instrument operation on the tissue. Specifically, the ultrasonic instrument can be in a high-power state in which the end effector vibrates while in contact with the tissue 104, thereby generating frictional heat to cut and seal the tissue.

[0096] This first stage also illustrates a notification 105 output by the surgical system. Specifically, the notification is displayed as a GUI item overlaid on top of the endoscopic video 103. Specifically, the notification includes the text "End Effector is Hot" to alert the operator to the temperature status of the end effector. In another aspect, the notification can be presented separately from (e.g., other) video and / or images displayed on the display 15. In one aspect, the notification can be output based on a controller determining the temperature of the end effector, as described herein. In some aspects, the notification can be presented when the temperature of the end effector reaches a threshold.

[0097] Stage 2 101 illustrates the results of cutting and sealing tissue using the end effector. As shown, the tissue has been cut into two pieces by the end effector and has also been cauterized. Furthermore, the gripper is now in an open position (with the articulated arm 31 moved away from the blade 30). With the tissue cut, the operator may no longer need to heat the end effector, and the instrument may therefore switch from a high-power state to a low-power state to enter a cooling cycle, as described herein. Therefore, at this stage, the ultrasonic instrument may be supplied with a current (e.g., via the generator 25) below a current threshold at which the instrument causes the blade of the end effector to generate (e.g., frictional) heat (e.g., upon contact with an object such as tissue). Furthermore, at this stage, the surgical system (controller 40 thereof) may be configured to estimate the temperature of the end effector based on a change in resonant frequency, which may be reduced at this stage, as described herein. Specifically, since the end effector has just entered a cooling cycle at this stage, the blade may still be hot (or above a temperature threshold). Specifically, 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 therefore, the notification 105 displayed on the display continues to read "END EFFECTOR IS HOT" to alert the operator that the end effector continues to have residual heat from the heating cycle.

[0098] The third stage 102 shows that the notification 105 has changed from "end effector is hot" to "end effector is cold." Specifically, this stage shows that after a certain period of time, the residual heat within the end effector has dissipated so that its determined temperature (e.g., based on a change in resonant frequency) has dropped below a temperature threshold, as described herein.

[0099] As described herein, the surgical system 1 can be configured to estimate the temperature of the end effector when the ultrasonic instrument is in a high-power state (e.g., actively used by the operator to cut and cauterize tissue) or a low-power state (e.g., a state in which the ultrasonic instrument has cooled after the operator has used the instrument to cut and cauterize tissue). In one aspect, the operator can switch between these two states one or more times during a surgical procedure. Once the operator switches from applying high power via the generator to the low-power state, the end effector can quickly begin to cool (e.g., to body temperature, such as approximately 37°C). If the operator were to switch back to the high-power state, the end effector would begin heating again. In some cases, the end effector may take some time to heat back to the desired temperature. In one aspect, the controller can be configured to maintain the desired temperature of the end effector in order to reduce the amount of time between cooling and heating cycles.

[0100] As described herein, the display 15 is arranged to present an endoscopic video 103 and a notification 105. In one embodiment, the generator's display 24 can display the video and / or the notification. For example, the display 24 can display the endoscopic video and the notification, or the notification can be displayed while the system's display 15 presents the endoscopic video.

[0101] Figure 11 1 is a flow chart of a process 110 for maintaining a desired temperature of an ultrasonic instrument (e.g., an end effector of an ultrasonic instrument). Specifically, a controller maintains the desired temperature by controlling whether the ultrasonic instrument is in a high-power state or a low-power state based on one or more changes in the resonant frequency of the end effector. In one aspect, the process can be performed automatically (e.g., without user intervention) such that the temperature of the end effector is maintained within (or within) a desired temperature range.

[0102] Process 110 begins when an operator uses an ultrasonic instrument during a surgical procedure and the controller 40 determines a change in the resonant frequency of the end effector (e.g., blade) of the ultrasonic instrument (at 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 (at block 112) by applying the change in resonant frequency as an input to a hysteresis model (e.g., model 45) that produces temperature as an output. The controller determines a desired temperature range for the end effector (at 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., between 300° C. and 315° C.). In another aspect, the temperature range may include all temperature values ​​above a specific temperature value. In this case, the temperature range may be a single temperature value (e.g., 300° C.) above which the end effector is configured to operate. In this case, the desired temperature range may be a specific user-desired (or user-defined) temperature. For example, the operator may desire a specific temperature to perform a surgical task on a specific tissue mass. In another aspect, the desired temperature range is determined based on user input via an input device communicatively coupled to the surgical system (e.g., via a touch-sensitive display screen of an electronic device). In another aspect, the desired temperature range can be determined based on the tissue of the patient on which the end effector of the ultrasonic instrument will perform the surgical task. For example, the controller can receive endoscopic video of a surgical site and execute an image identification algorithm on the video to identify a tissue mass in the site on which the ultrasonic instrument will perform the surgical task (e.g., resection, etc.). The controller can determine the desired temperature based on the identified tissue mass. For example, due to the amount of additional heat that may be required to cut and cauterize fatty tissue, fatty tissue may have a higher temperature range than thinner tissue.

[0103] The controller 40 maintains a desired temperature range for the end effector by switching between the following states based on the determined temperature: a high-power state, in which the ultrasonic instrument draws a first current to cause the end effector to generate heat; and a low-power state, in which the ultrasonic instrument draws a second current, less than the first current, and does not generate heat at the end effector (at block 114). Specifically, the controller maintains the temperature of the end effector within a desired range. This can be accomplished by determining whether the determined temperature of the end effector is within a temperature range (e.g., including a boundary value). In response to determining that the determined temperature is greater than the desired temperature range (or value), the ultrasonic instrument is configured to operate in the low-power state (e.g., to cause the end effector to not generate heat because it is sufficiently hot). Conversely, in response to the controller determining that the desired temperature is less than the desired temperature range, the ultrasonic instrument is configured to operate in the high-power state (e.g., to generate heat).

[0104] In one aspect, when the ultrasonic instrument is being used by an operator, the temperature of the end effector can be maintained within a desired temperature range (or within it). Specifically, the system can maintain the temperature while the operator performs a surgical task (such as cutting and / or cauterizing tissue) with the instrument.

[0105] In one aspect, the controller may continuously perform at least some of these operations in order to maintain a desired temperature range for the end effector (e.g., while the ultrasonic instrument is being used by an operator). Thus, the operations performed by the controller functionally create a "software sensor" in which the state of the ultrasonic instrument is controlled based on changes in resonant frequency rather than using temperature sensor data from a temperature sensor. Thus, a desired temperature range is determined and maintained without (e.g., the surgical system) using (and / or having) a temperature sensor.

[0106] As described herein, the ultrasonic instrument 20 can be a laparoscopic instrument held and manipulated by an operator. In another embodiment, the instrument can be part of a surgical robotic arm. For example, the ultrasonic instrument can be coupled to the distal end of the robotic arm (e.g., Figure 14 ), wherein movement and operation of the ultrasonic instrument can be performed via one or more user controls (e.g., a UID, a foot pedal, etc.) coupled to the surgical system. In some embodiments, the ultrasonic instrument can be coupled to the arm and controlled by the generator based on user input. For example, the generator can control the rotational position of the articulated arm 31 to open or close the gripper 23 based on user input via one or more user input devices (such as the UID 14) communicatively coupled to the generator, as described herein. In another aspect, the generator can 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 position and / or rotational position of the articulated arm can be controlled by the controller 40 (e.g., based on user input received by the controller).

[0107] Figure 12 is used to create a hysteresis model (e.g., Figure 4 FIG. 1 is a flow chart of a process 120 for creating a model 45 in a surgical system. In one aspect, the process (or at least some operations of the process) can be performed in a controlled environment. In this case, the model can be predefined so that it is created and is part of the surgical system for use during the surgical procedure.

[0108] The process 120 begins by experimentally determining a first set of temperature data relative to a change in the resonant frequency of the end effector (at box 121). Specifically, the experimental data is determined for an end effector of an ultrasonic instrument that is configured to operate in either: 1) a high power state in which the instrument draws power for the end effector to generate heat; or 2) a low power state in which the instrument draws less power that does not generate heat in the end effector, as described herein. In one aspect, the temperature data may include temperature values ​​of the end effector relative to the resonant frequency (e.g., a change in the resonant frequency) when heating and cooling the end effector. 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 discrete 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 may generate a temperature difference between the end effector and the resonant frequency of the end effector by heating the end effector to a maximum temperature (e.g., T max ) and then cooled to a minimum temperature (e.g., T min ) to obtain the main hysteresis loop (for example, Figure 5 In some aspects, the controller may also derive one or more internal decreasing (and / or increasing) temperature profiles, each of which begins at a particular change in resonant frequency.

[0109] The controller uses the first temperature data set to determine additional temperature data relative to the change in the resonant frequency of the end effector as a second temperature data set (at block 122). Specifically, the controller determines (or identifies) missing sampling points based on available experimental data that cannot or was not experimentally determined. In some aspects, the controller may use one or more methods to determine the additional temperature data. For example, the controller may be configured to perform interpolation between at least two adjacent temperature curves determined experimentally. For example, the controller may use two of the closest cooling (reduction) curves available in the experimental data (e.g., the curves having the closest frequency change at the beginning of the cooling cycle, from T max Specifically, the controller may represent the frequency change of each adjacent curve at the start of cooling by ΔRFstart1 and ΔRFstart2, wherein the frequency change of the cooling curve to be interpolated may be in ΔRFstart x Start at 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 ​​T1 and T2 for the two curves can be obtained based on experimental data. Using these temperature values ​​and the corresponding change in resonant frequency, the change F with respect to resonant frequency can be obtained using the following equation: x The temperature value T of the interpolation curve x :

[0110]

[0111] When adjacent curves are present in the experimental data, the interpolation method can provide sufficient temperature data for the end effector to fill in the required sampling points in the hysteresis model. However, in some aspects, if only a small number of curves (e.g., less than a threshold number of curves) are available (e.g., due to minimal experimental data being available) and / or the available experimental data does not span the entire range of possible variations in resonant frequency and end effector blade, the controller can perform a polynomial fitting method to obtain (at least some) additional temperature data. This method will now be described.

[0112] First, the controller may fit a polynomial / function on each (or at least some) experimentally available curve (e.g., modeling the end effector temperature as a function of the change in resonant frequency on the curve). For example, for 1…n curves, each curve may be fit to a second-order polynomial such as

[0113] T1(ΔRF)=a1ΔRF 2 +b1ΔRF+c1

[0114] …

[0115] Tn (ΔRF) = a n ΔRF 2 +b n ΔRF+c n

[0116] Thus, temperature is a polynomial function of ΔRF. Thus, T=p(ΔRF), where p is a second-order polynomial with input ΔRF. On the other hand, temperature may be another function (e.g., a third-order polynomial). In one aspect, each of the curves may be a decreasing curve and / or an increasing curve, as described herein. In one aspect, each of the coefficients a, b, and c may be associated with a specific change value of the resonant frequency at the beginning (start) of the corresponding curve. Specifically, when the curve is an inner decreasing curve, the coefficients may be tied in association with the values ​​at the start of the cooling cycle. In one aspect, the controller may find a fit that best describes the change in one or more coefficients as a function of the corresponding starting change in resonant frequency, which may be shown as:

[0117] a1=x a ΔRFstart1+y a

[0118] …

[0119] a n =x a ΔRFstart n +y a

[0120] b1=x b ΔRFstart1+y b

[0121] …

[0122] b n =x b ΔRFstart n +y b

[0123] c1=x c ΔRFstart1+y c

[0124] …

[0125] c n =x c ΔRFstart n +y c ;

[0126] therefore

[0127] a=p a (ΔRFstart) = x aΔRFstart+y a

[0128] b=p b (ΔRFstart) = x b ΔRFstart+y b

[0129] c=p n (ΔRFstart) = x c ΔRFstart+y c

[0130] In one aspect, once these correlations are identified based on experimentally available data, the controller uses these correlations to generate further data to complete the missing sample points of the model. For a sample point on a particular cooling curve, the resonant frequency ΔRFstart associated with the fit of the particular cooling curve can be calculated. x Initial change of coefficients.

[0131] a x =p a (ΔRFstart x )

[0132] b x =p b (ΔRFstart x )

[0133] c x =p c (ΔRFstart x )

[0134] The controller may use a fitting function to calculate the end effector temperature at each discrete value of the change in resonant frequency along the cooling curve, as

[0135] T(ΔRF i )=p(ΔRFi)=a x ΔRF i 2 +b x ΔRF i +c x

[0136] As described herein, the controller may use a polynomial fit method to interpolate temperature values ​​and / or calculate temperature values ​​along the cooling curve. In another aspect, the controller may perform any (or both) of these methods to determine temperature data for a heating (or increasing) curve, which may begin along a main decreasing temperature curve of a main hysteresis loop.

[0137] Returning to process 120, the controller uses the first and second temperature data sets to generate a hysteresis model that includes a hysteretic relationship between the change in the resonant frequency of the end effector and the temperature (at block 123). Specifically, the controller determines an on / off threshold (α, β) for each hysteron and a weighting factor μ for each hysteron. For example, the controller discretizes the input domain (e.g., the change in resonant frequency), where each hysteron is defined by one or more discrete levels. The controller determines the weight of each hysteron by forming a temperature table (e.g., a lookup table) using the temperature information (e.g., the first and second temperature data sets). 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., a threshold amount), 4) again, the controller may tabulate the corresponding end effector temperature, and 5) the controller may continue decreasing the change in resonant frequency and tabulating the corresponding temperature values ​​until the change in resonant frequency reaches zero. In one aspect, the controller may repeat steps 1) to 5) until a reaches the maximum possible resonant frequency change.

[0138] In one aspect, the resulting temperature table is used to calculate a weight factor for each hysteron based on the individual contribution of each unit to the output (e.g., end effector temperature). Defining the blade temperature corresponding to αi and βi (listed in rows i and j of the resulting table) as f(i, j), the corresponding weight factor is calculated based on:

[0139] μ(i,j)=f(i+1,j+1)+f(i,j)–f(i+1,j)–f(i,j+1)

[0140] In one aspect, the diagonal elements of the table are i=j=k, and the weight factors are calculated based on:

[0141] μ(k,k)=f(k+1,k+1)–f(k+1,k)

[0142] In some aspects, the determined weight factors can be stored in a table, where each cell in the table is the weight μ for a separate hysteron having a distinct on-level α and off-level β. Thus, when using a hysteresis model to determine the temperature of the end effector, the weight factors can be determined by performing a table lookup based on one or more hysterons of the model.

[0143] In one aspect, a method performed by a surgical system comprising an ultrasonic instrument having an end effector comprises: experimentally determining a first temperature data set of changes relative to a resonant frequency of the end effector of the ultrasonic instrument, the ultrasonic instrument being configured to operate in either: 1) a high power state in which the ultrasonic instrument draws power for generating heat in the end effector; or 2) a low power state in which the ultrasonic instrument draws less power that does not generate heat in the end effector; using the first temperature data set to determine additional temperature data relative to changes in the resonant frequency of the end effector as a second temperature data set; and using the first temperature data set and the second temperature data set to generate a hysteresis model comprising a hysteresis relationship between changes in the resonant frequency of the end effector and temperature.

[0144] As previously mentioned, one aspect of the present disclosure can be a non-transitory machine-readable medium (such as a microelectronic memory) having stored thereon instructions that program one or more data processing components (collectively referred to herein as "processors") to (automatically) perform ultrasonic instrument operations and / or temperature estimation and notification operations, as described herein. In other aspects, some of these operations can be performed by specific hardware components containing hardwired logic. These operations can alternatively be performed by any combination of programmed data processing components and fixed hardwired circuit components.

[0145] Although certain aspects have been described and illustrated in the accompanying drawings, it should be understood that such aspects are merely illustrative of the present disclosure and not restrictive, and that the present disclosure is not limited to the specific constructions and arrangements shown and described, as various other modifications may occur to those skilled in the art. Accordingly, this description should be regarded as illustrative and not restrictive.

[0146] In some aspects, the present disclosure may include language such as, “at least one of [element A] and [element B]”. The language 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 present disclosure may include language such as, “[element A], [element B], and / or [element C]”. The language may refer to any one of these 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”.

Claims

1. A method performed by a surgical system comprising an ultrasonic instrument having an end effector, the method comprising: determining a change in a resonant frequency of the end effector when the ultrasonic instrument is in: 1) a high power state in which the ultrasonic instrument draws a first current causing the end effector to generate heat; or 2) a low power state in which the ultrasonic instrument draws a second current less than the first current that does not cause the end effector to generate heat; determining a temperature of the end effector by applying the change in resonant frequency to a hysteresis model, the hysteresis model including a hysteresis relationship between a change in resonant frequency of the end effector and a corresponding temperature of the end effector; as well as A notification is output based on the temperature.

2. The method according to claim 1, wherein: Determining the temperature of the end effector comprises: When the change in the resonant frequency is a positive value, determining the temperature as a first temperature; and When the change in the resonant frequency is a negative value, the temperature is determined to be a second temperature that is less than the first temperature.

3. The method according to claim 1, wherein: The hysteresis model includes a hysteresis loop including a first temperature curve having a first plurality of temperatures relative to a plurality of changes in a resonant frequency and a second temperature curve having a second plurality of temperatures different from the first plurality of temperatures relative to the plurality of changes in the resonant frequency.

4. The method according to claim 3, wherein: Temperature values ​​in the first plurality of temperature values ​​increase relative to an increasing change in the resonant frequency, and temperature values ​​in the second plurality of temperature values ​​decrease relative to a decreasing change in the resonant frequency.

5. The method according to claim 3, wherein: The model further includes a set of internal reduction temperature curves contained within the hysteresis loop, each internal reduction temperature curve having a set of temperatures relative to a set of changes in resonant frequency, Wherein determining the temperature of the end effector comprises: selecting an inner reduction temperature profile from the set of inner reduction temperature profiles based on the change in resonant frequency being associated with a corresponding set of changes in resonant frequency; and The temperature in a corresponding set of temperatures of the inner reduction temperature profile corresponding to the change in resonant frequency is identified.

6. The method according to claim 5, wherein: The change in resonant frequency is a negative change in resonant frequency, the set of temperatures is a first set of temperatures, and the set of changes in resonant frequency is a first set of changes in resonant frequency, wherein the model further comprises a set of inner increasing temperature curves contained within the hysteresis loop, each inner increasing temperature curve having a second set of temperatures relative to a second set of changes in resonant frequency, wherein the method further comprises: determining a positive change in resonant frequency; selecting an inner increasing temperature profile based on the positive change in resonant frequency being associated with a respective second set of changes in resonant frequency; and A temperature higher than the temperature along the inner increasing temperature curve corresponding to the positive change in resonant frequency is identified.

7. The method according to claim 3, wherein: Each change in resonant frequency in the plurality of changes is associated with a corresponding temperature in the second plurality of temperatures and another corresponding temperature in the first plurality of temperatures, the other corresponding temperature in the first plurality of temperatures being greater than the corresponding temperature in the second plurality of temperatures.

8. The method according to claim 7, wherein: Determining the temperature includes: identifying the temperature corresponding to the change in resonant frequency using the first temperature curve when the ultrasonic instrument is in a high power state; and The second temperature curve is used to identify the temperature corresponding to the change in resonant frequency when the ultrasonic instrument is in a low power state.

9. The method according to claim 1, further comprising: determining a desired temperature range for the end effector; as well as The temperature of the end effector is maintained within the desired temperature range by controlling whether the ultrasonic instrument is in a high power state or a low power state based on one or more changes in a resonant frequency of the end effector.

10. The method according to claim 1, wherein: Outputting the notification includes at least one of the following: displaying the temperature on a display of the surgical system; and The speaker is driven by an audio signal including an audible warning related to the temperature.

11. A surgical system comprising: An ultrasonic instrument having an end effector: processor; and a memory having instructions that, when executed by the processor, cause the surgical system to: determining a change in a resonant frequency of the end effector while the ultrasonic instrument is in 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; as well as A notification is output based on the temperature.

12. The system according to claim 11, wherein: The instructions for determining the temperature of the end effector include instructions for: When the change in the resonant frequency is a positive value, determining the temperature as a first temperature; and When the change in the resonant frequency is a negative value, the temperature is determined to be a second temperature that is less than the first temperature.

13. The system according to claim 10, wherein: The temperature model includes a hysteresis loop including a first temperature curve having a first plurality of temperatures relative to a plurality of changes in a resonant frequency and a second temperature curve having a second plurality of temperatures different from the first plurality of temperatures relative to the plurality of changes in the resonant frequency.

14. The system according to claim 13, wherein: Temperature values ​​in the first plurality of temperature values ​​increase relative to an increasing change in the resonant frequency, and temperature values ​​in the second plurality of temperature values ​​decrease relative to a decreasing change in the resonant frequency.

15. The system of claim 13, wherein: The instructions for determining the temperature include instructions for: identifying the temperature corresponding to the change in resonant frequency using the first temperature curve while the ultrasonic instrument is in the heating cycle; and The second temperature curve is used to identify the temperature corresponding to the change in resonant frequency while the ultrasonic instrument is in the cooling cycle.

16. The system according to claim 11, wherein: The end effector includes a blade arranged to vibrate along a longitudinal axis of the end effector, wherein the blade 1) vibrates at a first offset when the ultrasonic instrument is in the heating cycle, and 2) vibrates at a second offset that is less than the first offset when the ultrasonic instrument is in the cooling cycle.

17. The system of claim 11, wherein: The memory has further instructions to: determining a desired temperature range for the end effector; and The temperature of the end effector is maintained 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 system of claim 11, wherein: The instructions for outputting the notification include at least one of: displaying the temperature on a display of the surgical system; and The speaker is driven by an audio signal including an audible warning related to the temperature.

19. The system of claim 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 comprising an ultrasonic instrument having a blade, the method comprising: determining a change in a 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 that produces the temperature as an output; as well as maintaining a desired temperature range for the blade by switching between the following states based on the determined temperature: a high power state in which the ultrasonic instrument draws a first current to cause the blade to generate heat; and a low power state in which the ultrasonic instrument draws a second current less than the first current and does not generate heat to the blade.

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