Method and system for estimating temperature of ultrasonic instrument

Abstract

A method performed by a surgical system is disclosed. The method determines that the ultrasonic instrument is in a low power state. The method determines a resonant frequency of an end effector of the ultrasonic instrument and determines a temperature of the end effector based on the resonant frequency. A notification is displayed on a display of the surgical system based on the temperature.

Description

Technical Field

[0001] Various aspects of the present disclosure relate generally to surgical systems, and more particularly to surgical systems for estimating the temperature of an ultrasonic instrument. 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 multiple small incisions to be made in the patient's body (e.g., in the abdomen), through which several surgical tools (such as endoscopes, knives, graspers, and needles) are then inserted into the patient's body. Gas is injected into the abdomen, which inflates the abdomen, thereby providing more space around the end of the tool, making it easier for the surgeon to see (via an endoscope) and manipulate tissue at the surgical site. MIS can be performed faster and with less fatigue for the surgeon using a surgical robotic system, in which surgical tools are operably attached to the distal end of a robotic arm, and a control system actuates the arm and its attached tools. When the surgeon manipulates a handheld user input device (UID), the end of the tool will simulate 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 surgical arms have attached surgical instruments for performing certain surgical actions.

[0003] Control inputs from a user (e.g., a surgeon or other operator) are captured via one or more user input devices and then translated into control of the robotic system. For example, when a surgical tool is positioned at a surgical site of 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 quickly generate heat for cutting and cauterizing tissue. The tip may include a knife that reaches a high temperature (e.g., greater than 300° C.) during a "heating" cycle in which the knife oscillates against the mass of tissue, thereby generating heat during the oscillation due to friction between the knife and the tissue. After reaching the high temperature, the knife can be used to cut a portion of the tissue while also sealing the remaining tissue. The use of tools during laparoscopic surgery reduces instrument changes and the number of instruments during the procedure by performing multiple tasks (e.g., cutting, cauterizing, etc. for dissection).

[0005] Conventional laparoscopic surgical systems may be able to estimate the temperature of the blade of an ultrasonic instrument during a heating cycle of the blade. Specifically, such systems may activate the instrument by providing power (e.g., in response to receiving a user input from an operator, such as pressing on a pedal) for the blade of the instrument to oscillate, such as it is used to dissect tissue. When the instrument is active, the system may determine the temperature of the blade based on one or more characteristics of the instrument (e.g., input voltage, input current, etc.). However, after the heating cycle is terminated (e.g., the operator releases the pedal), the conventional system stops supplying power to the ultrasonic instrument. At this point, the blade enters a "cooling" cycle, in which the heat generated during the heating cycle is dissipated because the blade is no longer oscillating and therefore no frictional heat is generated. During this cooling cycle, conventional laparoscopic surgical systems do not provide the operator of the instrument with the real-time temperature of the blade. Specifically, these systems may be unable to determine the (e.g., current) temperature of the blade because the characteristics used to determine the temperature during the heating cycle (e.g., input voltage) are no longer available because the instrument is not powered. Therefore, if the operator manipulates the surrounding tissue with the instrument while the blade is still hot (e.g., before the end of a cooling cycle in which the blade is below a temperature threshold), the residual heat on the blade may inadvertently cause thermal damage to potentially sensitive tissue. In addition, the operator may not know with reasonable certainty the exact moment when the residual heat has dissipated enough for the ultrasonic instrument to be used to manipulate (or touch) tissue without causing damage. For example, the temperature of the blade may vary during use based on the type / thickness of tissue that the operator is actively cutting / cauterizing. Due to the varying temperature, the blade may cool differently once the task is completed and the instrument enters its cooling cycle. Therefore, there is a need for a surgical system that is configured to estimate (or predict) the temperature of an ultrasonic instrument when the instrument is not using ultrasonic vibrations to heat its blade (e.g., when in a cooling cycle).

[0006] The present disclosure provides a surgical system that estimates the temperature of an ultrasonic instrument when the ultrasonic instrument is in a "low power" state (or cooling cycle) in which the instrument does not draw (e.g., sufficient) power to heat an end effector of the instrument. The system determines that the ultrasonic instrument is in a "low power" state (or cooling cycle) in which the ultrasonic instrument does not draw (e.g., sufficient) power to heat the end effector as the ultrasonic instrument would during a "high power" state (or heating cycle) in which the ultrasonic instrument draws power to heat the end effector. For example, the ultrasonic instrument may be coupled to a generator that is arranged to provide current to the instrument based on a received user input (e.g., an operator pressing on a pedal). With this current, the instrument may cause the blade of the end effector to vibrate to generate heat at an elevated temperature. However, when in this low power state, the ultrasonic instrument may draw less power (e.g., be provided with less current) to cause the blade to vibrate less than when the instrument is in a high power state. This lesser vibration may not be sufficient to cause the blade to generate heat. When the ultrasonic instrument is in this low power state, the system can determine the resonant frequency of the end effector (e.g., the blade when vibrating at an excursion lower than that required to generate heat). The system determines the temperature of the end effector based on the resonant frequency. For example, the system can apply the resonant frequency (which can be at least one input) to a (e.g., predefined) model that produces a temperature as an output. The system can display a notification on a display based on the temperature, such as displaying the determined temperature. Thus, the present disclosure can provide real-time temperature information to help the operator assess whether the end effector is within a safe range for contact with tissue, rather than leaving the operator guessing whether the end effector has cooled.

[0007] In one aspect, the end effector can be a gripper including a blade (e.g., as a jaw) that vibrates along a longitudinal axis of the blade to generate heat when the ultrasonic instrument is in a high power state, as described herein. In addition, the gripper can include an articulated jaw that is rotatably coupled to a joint of the gripper, wherein the articulated jaw is arranged to rotate relative to the blade to open or close the gripper. In some aspects, the resonant frequency can be determined in response to determining that the gripper is in an open position in which the articulated jaw is rotated away from the blade.

[0008] The above summary does not include 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 and those disclosed in the detailed description below and specifically pointed out in the claims. Such combinations may have specific advantages not specifically recited in the above summary. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Various aspects are illustrated in the figures of the accompanying drawings by way of example and not limitation, wherein like reference numerals indicate similar elements. It should be noted that references to "one" or "an" aspect of the present disclosure are not necessarily to the same aspect, and that they refer to at least one. In addition, for the sake of brevity and to reduce the total number of drawings, a given drawing may be used to illustrate features of more than one aspect, and not all elements in the drawings may be required for a given aspect.

[0010] Figure 1 A pictorial view of an exemplary surgical system in a surgical setting is shown.

[0011] Figure 2 A pictorial view of an ultrasonic instrument and generator according to one aspect of the present disclosure is shown.

[0012] Figure 3 Shows Figure 2 The end effector of an ultrasonic instrument.

[0013] Figure 4 is a block diagram of a surgical system according to one aspect.

[0014] Figure 5 is a flow chart of a process for determining the temperature of an end effector of an ultrasonic instrument in a low power state.

[0015] Figure 6 Several 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.

[0016] Figure 7 is a flow chart of an aspect process for determining the temperature of an end effector. DETAILED DESCRIPTION

[0017] Several aspects of the present disclosure are now 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 explicitly 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 clearly contrary, all ranges listed herein are deemed to include the endpoints of each range.

[0018] Figure 1A 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 The example of the operating table or bed on which the patient is located is shown. 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 can be combined with 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 operation (surgical procedure). The surgical tool 7 can be an end effector attached to the distal end of the surgical arm 4 for performing a surgical procedure.

[0019] 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 entering, viewing, or manipulating the internal anatomical structure of a patient 6. On the one hand, a 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, an 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).

[0020] Generally, a remote operator 9 (such as a surgeon or other operator) may use the user console 2 to remotely manipulate the arm 4 and / or attached surgical tools 7, for example during a remote operation. The user console 2 may be located in the same operating room as the rest of the system 1, such as in a remote operating room. Figure 1As 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 (UID) 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., static images and / or videos). 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 (surgery) presentation. For example, during a surgical procedure, one or more endoscopic cameras may capture image data of a 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).

[0021] On the other hand, the display 15 may be configured to display at least one graphical user interface (GUI) that can provide information and / or interactive content, thereby assisting the user in performing surgical procedures through one or more instruments in the surgical system 1. For example, some of the displayed content may include image data captured by one or more endoscopic cameras, as described herein. On the other hand, the GUI may include selectable UI items that, when manipulated by the user, may cause the system to perform one or more operations. For example, the GUI may include UI items as interactive content to switch control between robot arms. In one aspect, in order to interact with the GUI, the system may include an input device (such as a keyboard, a mouse, etc.). On the other hand, the user may use the UID 14 to interact with the GUI. For example, the user may manipulate the UID to navigate through the GUI (e.g., using a cursor), and to make a selection, the cursor may hover over the UI item and manipulate the UID (e.g., select a control or button). In some aspects, the display may be a touch-sensitive display screen. In this case, the user may perform a selection by navigating and selecting via the touch display. In some aspects, any method may be used to navigate and / or select UI items.

[0022] As shown, the teleoperator 9 sits in the chair 10 and views the user display 15 while manipulating the foot control 13 and the handheld UID 14 to remotely control one or more of the arm 4 and the surgical tool 7 (which is mounted on the distal end of the arm 4).

[0023] In some variations, the bedside operator 8 can also operate the system 1 in an "in bed" mode, where the bedside operator 8 (user) is now located on the side of the patient 6 and manipulates the robot-driven tools (the end effector attached to the arm 4) at the same time, for example, holding the handheld UID 14 and the manual laparoscopic tools with one hand. For example, the left hand of the bedside operator can manipulate the handheld UID to control the robotic components, while the right hand of the bedside operator can manipulate the manual laparoscopic tools. Therefore, in these variations, the bedside operator 8 can perform both robot-assisted minimally invasive surgery and manual laparoscopic surgery on the patient 6.

[0024] 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 arm of the system 1 is in a stowed configuration or a withdrawn configuration, the initial access to the surgical site (to facilitate access to the surgical site) can be performed manually. Once the access is completed, the initial positioning or preparation of the system 1 (including its arm 4) can be performed. Then, the surgical operation continues, wherein the remote operator 9 at the user console 2 uses 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 bed or operating table by a bedside person (e.g., a bedside operator 8) wearing a sterile surgical gown, and the bedside person can perform tasks on one or more arms in the robot arm 4, such as retracting tissue, performing manual repositioning, and tool replacement. Non-sterile personnel may also be present to assist the remote operator 9 at the user console 2. When the procedure or surgical operation is completed, 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 inputting or printing healthcare records via the user console 2 .

[0025] In one aspect, the remote operator 9 holds and moves the UID 14 to provide input commands to drive (move) one or more robot arm actuators 17 (or drive mechanisms) in the robotic system 1 for remote operation. The UID 14 may be communicatively coupled to the rest of the system 1, for example, via a console computer system 16 (or host). The UID 14 may generate a spatial state signal 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 signal may be an input signal to control the movement of the robot arm actuator 17. The system 1 may use a control signal derived from the spatial state signal to control the proportional movement of the actuator 17. In one aspect, the console processor of the console computer system 16 receives the spatial state signal and generates a corresponding control signal. Based on these control signals that control how the actuator 17 is powered to drive the segments or connectors of the arm 4, the movement of the corresponding surgical tool attached to the arm may simulate the movement of the UID 14. Similarly, interaction between the remote operator 9 and the UID 14 may generate, for example, a grasp control signal that causes the jaws of a grasper of the surgical tool 7 to close and grasp tissue of the patient 6 .

[0026] The system 1 may include several UIDs 14, wherein respective control signals are generated for each UID controlling the actuators and surgical tools (end effectors) of the respective arms 4. For example, the teleoperator 9 may move the first UID 14 to control the movement of an actuator 17 located in the left robotic arm, wherein the actuator responds by moving a link, gear, etc. in the arm 4. Similarly, the movement of the second UID 14 by the teleoperator 9 controls the movement of another actuator 17, which in turn drives other links, gears, etc. of the system 1. The system 1 may include a right arm 4 fixed 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. The actuator 17 may include one or more motors that are controlled so that they drive the joint of the arm 4 to rotate, for example, to 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. The UID 14 may also control the movement of the respective 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 .

[0027] In some aspects, the communication between the surgical robotic table 5 and the user console 2 can be performed 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., optical fiber) and / or a wireless link, using any suitable data communication protocol in a variety of wireless data communication protocols, such as the Bluetooth protocol. Any wired connection can optionally be built into the floor and / or wall or ceiling of the operating room. The system 1 can provide video output to one or more displays (including displays in the operating room and remote displays accessible via the Internet or other networks). 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.

[0028] Figure 2 A 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 surgery (e.g., cutting and sealing tissue) based on manual operation of the instrument by an operator (e.g., a surgeon) (e.g., manual operation of a handle 21). The ultrasonic instrument is coupled to (e.g., via a cable) a generator that enables the ultrasonic instrument to operate in one or more power states, as described herein.

[0029] 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, which may be coupled to a shaft of the instrument).

[0030] 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 a 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.

[0031] 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 knife) 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 a generator 25).

[0032] As currently described, the ultrasonic instrument may include an end effector 23 and a tool driver 21. In one aspect, the ultrasonic instrument may be detachable from the tool driver (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., coupled 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) so as to be coupled to the instrument. By being separated from the handle, this may allow a plurality of 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.).

[0033] 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.

[0034] As currently 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 1The robotic arm 104 may include a plurality of connectors and a plurality of braked 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.

[0035] 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., UID, 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).

[0036] Steering Figure 3 , the figure shows Figure 2 The end effector 23 of an ultrasonic instrument. Specifically, the figure shows that the end effector is a gripper (or gripping device) received by the sleeve 22 and includes a knife 30 (e.g., as a jaw) and an articulated arm (or jaw) 31, which is rotatably coupled to a joint (or robot wrist) 32. Specifically, the knife is received (and extended) through the sleeve and is arranged to be coupled to a tool driver (e.g., of the handle 21) so that the knife vibrates back and forth within the sleeve. The articulated arm 31 (at the joint 32) is rotatably coupled to the sleeve 22 and is arranged to be rotatable. The gripper is arranged to open and close based on the rotational position of the articulated arm around the rotation axis of the joint (e.g., the Z axis) relative to the knife (and / or sleeve). For example, the gripper is arranged to open (or be in an open position) when the articulated arm is rotated away from the knife (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., squeeze the object between the jaws) in order to grasp the object and / or perform dissection on the object.

[0037] As described herein, the knife 30 is the jaws of the gripper. Specifically, the knife is a jaw that cannot rotate relative to the end effector (e.g., around the Z axis). The knife can be arranged to vibrate along the longitudinal axis of the knife (e.g., the Y axis) to generate heat when the ultrasonic instrument is in a high power state (or mode). Specifically, the knife 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 sleeve, as described herein) so as to repeatedly shift the knife 30 at a certain (e.g., constant) frequency. Specifically, the knife can vibrate (e.g., reciprocate back and forth) on an offset (or displacement), wherein the knife moves a certain distance from a starting position (e.g., forward or away from the end effector) and then moves back the distance. In one aspect, the offset can be the distance that the knife moves from the starting position to the extended position. On the other hand, the offset can be the distance that the knife moves forward and backward.

[0038] As described herein, the blade can generate frictional heat when it vibrates 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. When the blade vibrates, the end effector can cut and / or cauterize the 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 provided to the ultrasonic instrument). More information about the vibrating blade and the power state of the ultrasonic instrument is described herein.

[0039] Back to Figure 2, the 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 the operator (e.g., to manipulate tissue and / or perform one or more surgical tasks on tissue during laparoscopic surgery, such as to cut and seal blood vessels and / or cut, grasp and dissect tissue). 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 "heating 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 a (e.g., 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) offset (and at a specific frequency). When the blade of the end effector vibrates against the object (such as tissue) at this deflection, friction heat can be generated by the end effector, as described herein. In another aspect, the ultrasonic instrument can be arranged to operate in a "low power" state (or "cooling cycle"), in which the ultrasonic instrument no longer draws (sufficient or as much) power provided by 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, so that the end effector does not generate heat (e.g., when in contact with the 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 this does not cause the end effector to generate heat (or as much heat as when the ultrasonic instrument is in the high power state). Therefore, once the ultrasonic instrument enters the low power state from the high power state, the ultrasonic instrument can begin to cool. Eventually, if the low power state is maintained, the ultrasonic instrument will drop to (at least) a threshold temperature (e.g., room temperature). In one aspect, the second current may be less than a predefined threshold current. In one aspect, in the low power state, the blade may vibrate at the same frequency as in the high power state. In another aspect, the blade may vibrate within a tolerance frequency range.

[0040] Due to the lower current provided to the instrument when in the low power state, the blade of the end effector may be driven differently by the tool driver 21 than when the instrument is in the high power state. Specifically, the blade may 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 may vibrate at a first (e.g., high) offset, which may cause the blade to generate heat when pressed against an object, while when in the low power state, the blade may vibrate at a second (lower) offset, which may be less than the first offset (e.g., the blade is less displaced along the longitudinal axis than in the first offset). In some aspects, the second offset may be less than a minimum threshold (e.g., if the blade would vibrate at the minimum threshold, the blade would generate heat at the minimum threshold). In one aspect, the end effector may not generate frictional heat when vibrating at the lower offset and when vibrating upward against an object (such as a blood vessel). In one aspect, the resonant frequency is maintained within a tolerance range regardless of which power state the instrument is operated in.

[0041] In one aspect, the difference in vibration of the end effector may be based on the amount of power drawn by the ultrasonic instrument when in different states. For example, the offset that the blade displaces when it oscillates may be based on the power drawn by the instrument (e.g., proportional to the power), whereby more power drawn by the instrument may cause the blade to vibrate at a high offset. Conversely, when the ultrasonic instrument is in a low-power state, the instrument may draw less power, which causes the blade to vibrate less (compared to when the instrument is in a 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 a low-power state and in contact with an object, but it may be less than the heat generated when the instrument is in a high-power state. In this case, such generated frictional heat may not be sufficient to cut and / or seal tissue. In some aspects, due to operating in a low-power state, the end effector of the ultrasonic instrument may enter a cooling cycle, whereby the heat generated by the end effector when the instrument is in a high-power state is dissipated (e.g., within a certain period of time). On the other hand, the knife may not vibrate (eg, the tool driver 21 may not drive the knife) while in this low power state.

[0042] In one aspect, the system may 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 may 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 UID 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 may place the ultrasonic instrument in a high power state, wherein 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 may 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 toward the blade 30 by at least a threshold distance). 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).

[0043] In some aspects, the ultrasonic instrument may be arranged to switch between a high power state and a low power state. As described herein, when the generator is receiving user input (e.g., the user pulls or presses the trigger on the handle), the instrument may operate in a high power state. The instrument may operate in a low power state in response to the generator not receiving user input. For example, the ultrasonic instrument may switch from a high power state to a low power state in response to the user releasing the trigger on the handle (the generator may transition between these two states). In one aspect, the instrument may operate in a low power state while the operator is not actively using the instrument to perform ultrasonic instrument operations, as described herein. Specifically, the system may enter a low power state without user input being received in one or more input devices used by the operator to enter a high power state. However, once the operator wishes to actively use the ultrasonic instrument, the ultrasonic instrument may switch back to a high power state (e.g., in response to user input). On the other hand, the instrument may operate in a low power state in response to receiving user input (e.g., the user presses a button on the UID). On the other hand, the instrument may operate in this state for a period of time. As described herein, the surgical system is configured to determine the temperature of the end effector while in a low power state (e.g., after switching from a high power state) to notify the operator of the temperature, which may be high because the instrument has been operating in a high power state. Once the end effector cools to a certain temperature (e.g., equal to or below a predefined temperature), the generator can deactivate the instrument by stopping providing a lower current because at this temperature, if the end effector were to come into contact with tissue, the end effector may not cause thermal damage.

[0044] In one aspect, the generator may provide different levels of current to heat the blade, which may be based on user input. For example, the generator may receive a first user input (e.g., from one pedal coupled to the generator), and in response, provide a maximum (allowable) amount of current to the ultrasonic instrument. The ultrasonic instrument may then drive the end effector at a maximum (e.g., predeterminable) excursion, which may 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 may provide a lesser amount of current to the ultrasonic instrument. Thus, the ultrasonic instrument may draw less power to cause the end effector to vibrate at a (second) lower excursion, which may be lower than the first excursion at which the blade vibrates in response to the first user input. However, the lower excursion may cause the end effector to heat at a lower temperature than the first temperature of the end effector when the ultrasonic instrument draws a larger current (in response to the generator receiving the first user input). By heating the end effector to different temperatures, different types of tissue may 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 excursion).

[0045] As described herein, an ultrasonic instrument may 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 may be activated (e.g., by a user) so that the ultrasonic instrument may operate in a high power state so as to draw sufficient current to cause the end effector to generate heat. Specifically, the generator may activate the ultrasonic instrument to close the end effector (e.g., to cause the articulated arm 31 to move within the distance of the knife 30) upon receiving user input. Once the user input is received to move the articulated arm, the generator may be configured to provide (e.g., sufficient) power to activate the instrument, as described herein. In some aspects, the generator may activate the instrument based on determining that the articulated arm and / or the knife are in contact with the object. For example, the ultrasonic instrument may include one or more sensors (e.g., force sensors) that detect the presence of an object and / or detect that the object is in contact with both arms. Upon making this determination, the generator may provide a first current to cause the knife to oscillate so as to cause the knife to generate heat.

[0046] In one aspect, a surgical system (e.g., a generator of a surgical system) may 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 may be configured to keep track of (or monitor) characteristics such as an input voltage, an input current, a resonant state, and / or a resonant frequency of the ultrasonic instrument. In one aspect, the generator may be configured to monitor at least some of these characteristics of the instrument 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 may determine the resonant frequency of the end effector (e.g., the blade 30 of the end effector).

[0047] In one aspect, the surgical system can include additional components. For example, the system can include a cable connecting the 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.

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

[0049] 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 stand-alone 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 speakers.

[0050] In some aspects, 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 dedicated state machines). In one aspect, the controller can be part of an electronic device, such as a console computer system 16, a control tower 3, and / or a user console 2. Although shown as a single component, in one aspect, the controller can include one or more electronic components (e.g., processors, memories, etc.) that are communicatively coupled on a single electronic device (such as a console computer 16) or across multiple devices (e.g., communicating on a wireless computer network). In some aspects, the controller can be part of a separate device, such as part of a remote server that communicates with one or more electronic devices. In another aspect, the controller can be part of the generator 25 (e.g., at least partially integrated therein). In this case, at least some other elements (e.g., speakers and displays) can also be part of the generator (integrated therein). Therefore, at least some of the operations performed by the controller described herein can be performed by the generator.

[0051] As described herein, the controller is configured to perform temperature estimation operations for the surgical system 1 to determine the (e.g., real-time) temperature of an ultrasonic instrument (e.g., an end effector of an ultrasonic instrument) when the instrument is in a low-power state (e.g., not actively heated to cut and / or seal tissue). Specifically, the controller may determine the temperature based on one or more characteristics of the ultrasonic instrument determined when it is in the low-power state, such as the resonant frequency of the end effector (e.g., the blade of the end effector). At least some of the operations performed by the controller may be implemented in software (e.g., as instructions) stored in a memory of the surgical system (and / or stored in a memory of the controller) and executed by the controller, and / or may be implemented by a hardware logic structure. In one aspect, at least some of the operations performed by the controller may be performed each time the instrument enters a low-power state.

[0052] 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, a user input can be received via an ultrasonic instrument (e.g., when a user pulls on a trigger of a handle) to cause the generator to provide a current that switches the ultrasonic instrument from a low-power state to a high-power state, as described herein.

[0053] Figure 5is a flow chart of a process 60 for determining the temperature of an end effector of an ultrasonic instrument in a low power state. Specifically, at least some of the operations may be performed once and / or while the ultrasonic instrument is in a low power state. For example, the operations may be performed (e.g., each time) the ultrasonic instrument switches from a high power state to a low power state, which may be based on user input, as described herein. In this case, the surgical system may perform the operations to estimate the temperature of the ultrasonic instrument in real time and output (e.g., display) the temperature of the ultrasonic instrument to an operator of the instrument. In one aspect, the processes may be performed by the surgical system 1. For example, each of the processes may also be performed 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, the figure will refer to Figure 4 Give a description.

[0054] The process begins with the controller determining a baseline (or initial) resonant frequency of the end effector of the ultrasonic instrument 20 (at box 61). For example, the controller may determine the baseline resonant frequency of the blade 30 of the end effector at an initial time t0 as RF (t0). In one aspect, the controller may determine the baseline resonant frequency when the ultrasonic instrument 20 is coupled (e.g., inserted) into the generator 25. For example, once the instrument is inserted into the generator, the generator may perform one or more diagnostic operations on the instrument. Based on these operations, the generator may determine the baseline resonant frequency of the blade of the end effector and provide the frequency to the controller. In some aspects, the generator determines the resonant frequency electronically. For example, the generator may sense the voltage and current waveforms (and the phase angle difference between the two waveforms) used to drive the blade of the end effector. Specifically, the ultrasonic instrument 20 (e.g., a tool driver) may include an ultrasonic transducer that is configured to vibrate the blade according to the input voltage and current waveforms. The frequency that produces a phase angle difference of a threshold value (e.g., zero) is the resonant frequency. In one aspect, the generator continues to drive the ultrasonic transducer at resonance and can adjust the output voltage (which can be referred to as phase locking) to continue driving at resonance (when the resonant frequency changes with changes in temperature). In another aspect, the controller 40 can adjust the output frequency. In another aspect, other known methods can be used to determine the resonant frequency.

[0055] In some aspects, the baseline frequency can be determined when the end effector is at (or near) room temperature (e.g., a temperature between 20-25° C.). In another aspect, the baseline frequency can be determined once and stored in a memory of the surgical system 1 (e.g., a controller 25 of the surgical system). For example, the baseline frequency can be determined when the instrument is first coupled to the generator. In another aspect, the baseline resonant frequency can be determined each time an ultrasonic instrument is inserted into the generator. In another aspect, the baseline frequency can be determined at startup of the surgical system (e.g., ultrasonic instrument) (e.g., during initial power-on).

[0056] In one aspect, the operations performed in this block can be omitted from the process 60. For example, as described herein, at least some of these operations can be performed each time the ultrasonic instrument enters a low power state. However, in some aspects, the determination of the baseline frequency can be performed once (e.g., during initial power-on). Therefore, the process 60 can omit this operation in subsequent (at least partial) executions of the process.

[0057] When the ultrasonic instrument is in a low power state, the controller 40 is configured to determine that the end effector is in an open position (at box 62). Specifically, the controller may determine that the gripper 23 is in an open position in which the articulated arm 31 is rotated away from the blade 30 (e.g., by a threshold rotation distance). For example, the controller may determine that the ultrasonic instrument has received a user input (e.g., from a generator) to move the articulated arm 31 away from the blade 30. Specifically, the generator may provide an indication of the position of the articulated arm relative to the blade to the controller, and the controller may determine whether the end effector is open based on whether the distance between the two arms is equal to or greater than a threshold distance. On the other hand, the generator may provide the state of the end effector to the controller based on the position of the articulated arm (e.g., whether the end effector is in an open position or a closed position). On the other hand, the controller may determine that the end effector is in an open position using one or more signal processing operations based on one or more characteristics of the end effector. For example, the controller may receive a characteristic (such as a resonant frequency of the end effector) from the generator and determine whether the end effector is open based on the resonant frequency. In one aspect, the determination may be based on performing a signal processing operation on a first-order derivative of the resonant frequency.

[0058] The controller determines a starting (or initial) resonant frequency of the end effector (at box 63). Specifically, this can be a starting resonant frequency determined by the surgical system once (or in response to) the end effector of the instrument being in an open position (while also operating in a low power state). In one aspect, after the controller determines that the end effector is in the open position (e.g., immediately or within this time period), the controller can determine this starting resonant frequency of the blade 30 as the SRF. In one aspect, this starting frequency can be measured and provided by the generator, as described herein. The controller determines the difference between the starting resonant frequency and the baseline resonant frequency (at box 64). Specifically, the controller determines the difference as,

[0059] ΔSRF=SRF-RF(t0)

[0060] In one aspect, the difference ΔSRF represents the resonant frequency drift from the baseline (or nominal) resonant frequency to the starting resonant frequency of the blade (or a change therebetween). The controller 40 determines a heating duration (at block 65) in which the ultrasonic instrument was in a high power state before switching to a low power state. Specifically, the controller determines the amount of time the ultrasonic instrument was active (e.g., in a high power state) before operating in its current low power state. The heating duration (HD) may be represented as

[0061] HD=t heating end-t heating start

[0062] In this expression, t heating end represents the time when the ultrasonic device switches to a low power state, and t heating start is another time when the ultrasonic instrument enters the most recent high power state. In one aspect, t heating start is at heating end The time before.

[0063] The controller determines a starting (initial) normalized change in resonant frequency (at block 66). Specifically, such a normalized change in frequency may be an average drift rate of the starting resonant frequency when the ultrasonic instrument enters a low power state (e.g., and begins its cooling cycle because the ultrasonic instrument does not draw enough power to heat its end effector), such as

[0064]

[0065] The controller determines one or more model coefficients based on the initial normalized change in resonant frequency (at box 67). In one aspect, each of the coefficients may be determined based on the normalized change in resonant frequency (e.g., determined at box 66). In one aspect, the number of coefficients determined may be based on a particular model that may be used by the controller to determine the temperature of the end effector. For example, when the model is a third-order cooling polynomial model, the determined coefficients may include four coefficients (A, B, C, D), such as

[0066] A=C 11 *ΔSRF NORM +C 12

[0067] B=C 21 *ΔSRF NORM +C 22

[0068] C=C 31 *ΔSRFNORM +C 32

[0069] D=C 41 *ΔSRF NORM +C 42

[0070] In one aspect, eight constants C can be predefined in a controlled environment (e.g., a laboratory): 11 To C 42 . For example, the constants may be defined by fitting the "normalized starting resonant frequency" data to a third-order polynomial observed during modeling of one or more tissues using one or more ultrasonic instruments. For example, a temperature sensor (e.g., a pyrometer) may be used to measure the temperature of the end effector during one or more heating cycles and one or more cooling cycles of the end effector. During these measurements, one or more characteristics of the ultrasonic instrument as described herein may be determined (e.g., by the generator). For example, first, the end effector is in a closed position to grasp a mass of tissue. Then, the ultrasonic instrument may be activated (e.g., by a user) such that the instrument is in a high power state for a controlled period of time (e.g., one second, etc.). Thereafter, the instrument is switched (e.g., the generator is switched) to a low power state to end the heating cycle, the end effector is placed in an open position, and the tissue is removed from the jaws of the end effector (e.g., the end effector may be moved away from the tissue). In one aspect, once the end effector is moved away from the tissue (e.g., so that the tissue is no longer in contact with the jaws of the grasper), the cooling cycle may begin. In one aspect, the peak temperature of the end effector (when the instrument is in a high power state) will vary depending on the type / thickness of tissue being grasped and the activation during the heating cycle. The resonant frequency, temperature data of the ultrasonic instrument, and / or the duration of the heating cycle may be determined during the cooling cycle and may be used to determine one or more constants. In some aspects, the determined constants may be different based on the ultrasonic instrument used with the surgical system. In this case, the controller may be configured to determine the type of ultrasonic instrument coupled to the surgical system and may be configured to determine one or more constants based on the determined type.

[0071] As described herein, the model can be a third-order cooling polynomial model including four coefficients. On the other hand, the model can be a second-order polynomial model. In this case, the model can include the same or different number of coefficients.

[0072] The controller 40 determines a normalized change in the resonant frequency as a function of time (at box 68). Specifically, after determining the starting resonant frequency, the controller may continue to determine the resonant frequency of the end effector. For example, the generator may provide one or more measured resonant frequencies of the blade of the end effector after the starting frequency. In one aspect, the controller may receive one or more (subsequent) measured resonant frequencies (e.g., every millisecond, every second, every minute, etc.). For each determined resonant frequency RF, the controller may determine the drift from the baseline frequency as

[0073] ΔRF=RF-RF(t0)

[0074] The controller may determine a normalized change for all (or at least some) of the determined frequencies (e.g., where one or more resonant frequencies are determined after a starting resonant frequency) as a function of time, which may be defined as

[0075]

[0076] In one aspect, the function may be determined from one or more of the determined resonant frequencies. The controller 40 may estimate (or determine) the temperature of the end effector (at block 69) by applying the normalized change in resonant frequency and one or more model coefficients as inputs to a predetermined model that produces temperature as an output. Specifically, the controller may define the temperature as the following third-order polynomial model, which is a function of time

[0077] T(t)=A*(ΔRF NORM (t)) 3 +B*(ΔRF NORM (t)) 2 +C*ΔRF NORM (t)+D

[0078] Thus, the controller can determine the temperature of the blade of the end effector (e.g., at any given time) based on the change in the determined resonant frequency of the blade. Thus, by performing one or more temperature estimation operations described herein, the controller can determine (estimate) the temperature of the end effector based on one or more characteristics of the ultrasonic instrument (e.g., resonant frequency) without using a temperature sensor (e.g., data from a temperature sensor). In one aspect, the ultrasonic instrument may not include a temperature sensor.

[0079] The controller 40 is configured to output a notification based on the temperature (at box 70). 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 abdomen of a patient). On the other hand, the notification may indicate the state of the end effector (e.g., "hot"). On the other hand, 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. On the other hand, the audible notification may be a spoken word (e.g., "Attention! The knife is hot!"). On the other hand, any type of notification may be used.

[0080] In one aspect, the controller may perform one or more of these operations in real time so that the surgical system can (e.g., continuously) estimate the temperature and provide the temperature to the operator of the surgical system (e.g., when the ultrasonic instrument is in a low power state). In this case, the controller may continue to display the temperature of the end effector while the ultrasonic instrument is cooling. In some aspects, the system may stop providing notifications when the temperature of the end effector reaches a threshold. For example, the controller may determine whether the temperature is above a temperature threshold. In response to determining that the temperature is above the threshold, the controller may output a notification. However, if the temperature is about to fall below the threshold, the controller may stop outputting notifications, which may provide an indication to the operator that the end effector is no longer hot. On the other hand, 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 "The knife is cold").

[0081] In some aspects, the controller may be configured to determine the time when the temperature of the end effector will be below a temperature threshold. For example, as described herein, the controller determines the temperature of the end effector based on a polynomial model (or a particular order) as a function of time. In this case, the controller may use the model to estimate when the knife will be below the temperature threshold based on the rate of change of temperature relative to time. On the other hand, the controller may determine the time based on a change in the determined resonant frequency of the end effector. For example, when the ultrasonic instrument is in a low power state, the controller may receive one or more resonant frequencies after the initial resonant frequency. The controller may determine the time when the temperature will be below the temperature threshold based on the rate of change of subsequent (and initial) resonant frequencies. Once determined, the controller may be configured to include the time with the notification to provide an operator with an indication of when the end effector will be cold.

[0082] As described above, the surgical system is configured to determine the temperature of the ultrasonic instrument in order to output a notification, such as displaying the temperature on a display. This information can be used by the operator of the ultrasonic instrument (e.g., during a surgical procedure) to avoid using the instrument to contact surrounding tissue when the knife is still hot. Therefore, the operator can use this information to appropriately adjust how to manipulate the ultrasonic instrument (e.g., be more cautious to avoid contact with tissue). On the other hand, this information can be used by the operator to continue to perform ultrasonic surgery. For example, in the case where the end effector retains residual heat from when the instrument is activated, the operator can continue to use the instrument to perform one or more operations, such as sealing a blood vessel. In this case, the operator can use the displayed temperature to determine whether to continue using the instrument (e.g., based on whether the temperature of the end effector is hot enough to continue sealing the blood vessel) while the instrument is in a low-power state (e.g., without having to make the instrument react).

[0083] Some aspects may perform one or more variations of the process 60 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 continuous operations, and different specific operations may be performed in different aspects. As described herein, the process determines that the end effector is in an open position at box 62. In some aspects, the controller may wait to perform subsequent operations (e.g., 63 to 70) until the end effector is in this position. In this case, these operations of process 60 may be performed for a certain period of time after the ultrasonic instrument is switched to a low power state. This may be due to the operator of the surgical instrument maintaining the end effector in a closed position for a certain period of time when the instrument is in a low power state. On the other hand, at least some of these operations may be performed each time the ultrasonic instrument is activated (e.g., operated in a high power state). For example, the controller may determine one or more new model coefficients (e.g., at box 67) and thus create a new temperature estimation model after each activation of the ultrasonic instrument.

[0084] As described herein, the controller is configured to determine one or more model coefficients and estimate the temperature by applying the normalized change of the resonant frequency and the coefficients to a predetermined model. In one aspect, the controller may be configured to determine the model based on the ultrasonic instrument. Specifically, the model may be based on one or more physical characteristics of the instrument, such as the mechanical structure of the end effector of the instrument. In some aspects, at least some of these physical characteristics may be different between different ultrasonic instruments (for example, where the blades between the instruments are of different sizes / shapes). Due to the differences between the physical characteristics, the model used for the instrument may be different. For example, when the model is a polynomial model, the order of the model (for example, second order or third order) may be based on the physical characteristics of a particular instrument. In one aspect, the number of model coefficients may also be based on the characteristics of the instrument. In this case, the controller may be configured to determine an ultrasonic instrument (of one or more instruments) that is part of a surgical system (for example, coupled to the generator 25), and is configured to determine the model associated with the determined instrument (for example, the order of the polynomial model). In one aspect, the determination may be a table lookup of a data structure (with a table) that associates different types of ultrasonic instruments with one or more models (and / or model coefficients).

[0085] Figure 6 Several stages of a display of a surgical system are shown, the display showing actions performed by the end effector of the ultrasonic instrument and showing notifications based on the determined temperature of the end effector. Specifically, each of the three stages 70-72 shows a display 15 of the surgical system, which displays an endoscopic video 73. The video that may be provided by one or more endoscopic cameras of the system 1 shows a surgical site within a patient's body on which a surgical procedure is being performed. Specifically, the video 73 shows tissue 74 (e.g., a blood vessel) being manipulated by the end effector 23. On the other hand, the display may 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.

[0086] The first stage 70 shows that the end effector 23 is grasping (a portion of) tissue 74. 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 so that the tissue is sandwiched between (e.g., in contact with) the two arms. In addition, the ultrasonic instrument of the end effector 23 is used to perform an ultrasonic instrument operation on the tissue. Specifically, the ultrasonic instrument can be in a high power state, wherein the end effector vibrates while in contact with the tissue 74, thereby generating frictional heat to cut and seal the tissue.

[0087] The second stage 71 shows the result 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. In addition, the gripper is now in an open position (where the articulated arm 31 moves away from the knife). With the tissue cut, the operator may no longer need to heat the end effector, and therefore the instrument may be switched from a high power state to a low power state in order to enter a cooling cycle, as described herein. Therefore, at this stage, an electric current below a current threshold may be provided to the ultrasonic instrument (e.g., through the generator 25), at which current threshold, the instrument causes the knife to generate (e.g., friction) heat. In addition, the surgical system (controller 40) may estimate the temperature of the knife based on the resonant frequency of the knife when the current is provided to the instrument, as described herein. In one aspect, the controller may perform at least some of the operations described herein in order to estimate the temperature.

[0088] The third stage 72 shows a notification 75 being displayed as a graphical user interface (GUI) item overlaid on top of the endoscopic video 73. The notification is based on the estimated temperature of the knife. Specifically, the notification includes the text "Warning! The knife is hot!" to alert the operator to the temperature status of the knife. On the other hand, the notification may be presented separately from the (e.g., other) video and / or images displayed on the display 15. In one aspect, the surgical system may continue to determine the temperature of the knife and display the notification as the knife cools. In some aspects, the surgical system may remove the notification when the knife is equal to or less than a temperature threshold, thereby indicating to the operator that the knife is no longer hot.

[0089] As described herein, the display 15 is arranged to present the endoscopic video 73 and the notification. In one embodiment, the display 24 of the generator 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 display 15 of the system presents the endoscopic video.

[0090] Figure 7 8 is a flow chart of a process 50 for determining an aspect of a temperature of an end effector. Specifically, at least some of the operations in the process may be performed by the controller 40 of the surgical system. In another aspect, at least some of the operations may be performed by the generator 25. The process 50 begins with the controller 40 determining that the ultrasonic instrument 20 is in a low power state (at box 81). Specifically, the controller determines that the ultrasonic instrument is not drawing enough (sufficient) power (e.g., the generator 25 is not providing enough current) to heat the end effector 23 of the ultrasonic instrument (e.g., when the end effector is in contact with tissue). In one embodiment, the controller may receive an indication from the generator that it is providing less power (or is in a low power state). In another embodiment, the controller may receive an indication that an operator of the surgical system no longer wishes to actively use the instrument (e.g., based on user input) to perform heat-related surgical tasks (e.g., cutting, cauterization, etc.).

[0091] The controller determines the resonant frequency of the end effector (at block 82). The controller system determines the temperature of the end effector based on the resonant frequency (at block 83). Specifically, the controller may perform Figure 5 The controller displays a notification on a display of the surgical system based on the temperature (at box 84). For example, the notification may include the temperature of the end effector and / or may include a textual indication that the blade is hot, as described herein.

[0092] Some aspects may perform changes to the processes 60 and / or 80 described herein. For example, specific operations of at least some of the processes may not be performed in the exact order shown and described. Specific operations may not be performed in a series of continuous operations, and different specific operations may be performed in different aspects. For example, when the ultrasonic instrument is in a low-power state, the controller may determine the resonant frequency and temperature. In another embodiment, at least some of these operations may be performed after the ultrasonic instrument has been in a high-power state. For example, the controller may determine that the ultrasonic instrument is in a high-power state, where the instrument draws power (e.g., from the generator 25) to heat its end effector 23. For example, the controller may receive an indication from the generator that it is providing current to the instrument (e.g., based on user input) for the instrument to vibrate the end effector on the offset, which causes the generation of frictional heat when in contact with an object. Therefore, the ultrasonic instrument may be active, thereby allowing the operator of the surgical system to perform one or more ultrasonic instrument operations (e.g., cutting, sealing, etc.). The controller may switch the ultrasonic instrument to a low-power state based on satisfying one or more conditions, such as receiving an indication that the operator of the surgical system no longer wishes to actively use the instrument (e.g., based on user input). Once the ultrasonic instrument is switched to a low power state, at least some of the operations described herein may be performed to determine and display the temperature of its end effector.

[0093] 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 1The ultrasonic instrument may be coupled to the arm and controlled by the generator based on user input. For example, the generator may control the rotational position of the articulated arm 31 so as 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. On the other hand, the generator may adjust the spatial position (e.g., in space) of the end effector based on user input (e.g., based on the position of the UID). On the other hand, the spatial position and / or rotational position of the articulated arm may be controlled by the controller 40 (e.g., based on user input received by the controller).

[0094] As described herein, the surgical system is configured to estimate the temperature of the ultrasonic instrument when the ultrasonic instrument is in a low power state. In one aspect, the system may estimate the temperature based on user input. For example, when the operator of the ultrasonic instrument is not actively using the instrument (e.g., cutting and / or sealing tissue), the system may perform these estimation operations when the instrument is in this state. Specifically, the operation is performed during the cooling cycle of the instrument. On the other hand, when the instrument is actively used to perform ultrasonic instrument operations, at least some of these operations may be performed. Specifically, the controller 40 may perform closed-loop temperature control operations to maintain a specific end effector temperature when the operator actively uses the instrument. For example, when the operator actively uses the end effector (e.g., when the instrument is in a high power state, and when the knife of the end effector generates heat due to friction between the knife and the tissue grasped by the end effector), the controller may estimate the temperature of the end effector. In one aspect, the controller may estimate this "high state" temperature using any known method for estimating temperature when the ultrasonic instrument is in a heating cycle (e.g., adaptive tissue technology (ATT), controlled thermal management (CTM), etc.). The controller may compare the high state temperature to a temperature threshold. Upon determining that the high state temperature is equal to or greater than the temperature threshold (e.g., by a threshold amount), the controller may be configured to switch the ultrasonic instrument to a low power state. While switching to the low power state, the controller may continue to estimate the (e.g., "low state") temperature of the blade using one or more operations described herein. Upon determining that the low state temperature is below the temperature threshold (or below the threshold by a threshold amount), the controller may be configured to cause the ultrasonic instrument to react. Thus, the surgical system may adjust the current supplied to the ultrasonic instrument to maintain the temperature of the end effector.

[0095] As previously described, one aspect of the present disclosure may be a non-transitory machine-readable medium (such as a microelectronic memory) having instructions stored thereon that program one or more data processing components (collectively referred to herein as "processors") to (automatically) perform ultrasonic instrument operations and / or temperature estimation operations as described herein. In other aspects, some of these operations may be performed by specific hardware components containing hardwired logic. These operations may alternatively be performed by any combination of programmed data processing components and fixed hardwired circuit components.

[0096] Although certain aspects have been described and shown in the accompanying drawings, it should be understood that such aspects are merely illustrative of the present disclosure and not limiting, and 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. Therefore, this description should be regarded as illustrative rather than limiting.

[0097] 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, the method comprising: determining that the ultrasonic instrument is in a low power state; determining a resonant frequency of an end effector of the ultrasonic instrument; determining a temperature of the end effector based on the resonant frequency; as well as A notification is displayed on a display of the surgical system based on the temperature.

2. The method of claim 1, wherein the end effector is a gripper, the gripper comprising: 1) a knife that vibrates along the longitudinal axis of the knife; and 2) an articulating jaw rotatably coupled to a joint of the gripper.

3. The method according to claim 2, wherein: When the ultrasonic instrument is in the high power state, the blade vibrates at a first excursion, and when the ultrasonic instrument is in the low power state, the ultrasonic instrument draws less power to cause the blade to vibrate at a second excursion that is less than the first excursion.

4. The method of claim 2, further comprising determining that the gripper is in an open position in which the articulated jaw is rotated away from the blade, wherein the resonant frequency is determined in response to determining that the gripper is in the open position.

5. The method of claim 1 , further comprising determining a baseline resonant frequency of the end effector during initial power-up of the ultrasonic instrument, wherein the temperature of the end effector is determined based on a difference between the baseline resonant frequency and the resonant frequency.

6. The method of claim 5, further comprising determining a heating duration in which the ultrasonic instrument was in a high power state prior to being in the low power state, wherein determining the temperature of the end effector comprises applying the heating duration and the difference as inputs to a predefined model that produces the temperature as an output.

7. The method according to claim 1, wherein: The notification includes the determined temperature of the end effector.

8. The method according to claim 1, wherein: The resonant frequency is a first resonant frequency, wherein the method further comprises: determining a subsequent second resonant frequency of the end effector while the ultrasonic instrument is in the low power state; and determining a time at which the temperature of the end effector will be below a threshold based on a rate of change between the first resonant frequency and the second resonant frequency, The notification includes the time.

9. The method according to claim 1, further comprising: determining whether the temperature is above a threshold; as well as In response to determining that the temperature is above the threshold, at least one of: 1) displaying the notification including text indicating that the temperature is high, and 2) outputting a warning audio indicating that the temperature is high via one or more speakers of the surgical system.

10. A surgical system comprising: An ultrasonic instrument having an end effector: monitor; processor; and a memory having instructions that, when executed by the processor, cause the surgical system to: determining that the ultrasonic instrument is in a low power state; determining a resonant frequency of the end effector; determining a temperature of the end effector based on the received resonant frequency; as well as A notification is displayed on the display based on the temperature.

11. The surgical system of claim 10, wherein: The end effector is a gripper that includes: 1) a blade that oscillates along a longitudinal axis of the blade; and 2) an articulated jaw rotatably coupled to a joint of the gripper.

12. The surgical system of claim 11, wherein: When the ultrasonic instrument is in the high power state, the blade vibrates at a first excursion, and when the ultrasonic instrument is in the low power state, the ultrasonic instrument draws less power to cause the blade to vibrate at a second excursion that is less than the first excursion.

13. The surgical system of claim 11, wherein: The memory has further instructions for determining that the gripper is in an open position in which the articulating jaw is rotated away from the blade, wherein the resonant frequency is determined in response to determining that the gripper is in the open position.

14. The surgical system of claim 10, wherein: The memory has further instructions for determining a baseline resonant frequency of the end effector during initial power-up of the ultrasonic instrument, wherein the temperature of the end effector is determined based on a difference between the baseline resonant frequency and the resonant frequency.

15. The surgical system of claim 14, wherein: The memory has further instructions for determining a heating duration in which the ultrasonic instrument is in a high power state prior to being in the low power state, wherein the instructions for determining the temperature of the end effector include instructions for applying the heating duration and the difference as inputs to a predefined model that produces the temperature as an output.

16. The surgical system of claim 10, wherein: The notification includes the determined temperature of the end effector.

17. The surgical system of claim 10, wherein: The resonant frequency is a first resonant frequency, wherein the memory has further instructions for: determining a subsequent second resonant frequency of the end effector while the ultrasonic instrument is in the low power state; and determining a time at which the temperature of the end effector will be below a threshold based on a rate of change between the first resonant frequency and the second resonant frequency, The notification includes the time.

18. The surgical system of claim 10, wherein: The memory has further instructions for: determining whether the temperature is above a threshold; and In response to determining that the temperature is above the threshold, at least one of: 1) displaying the notification including text indicating that the temperature is high, and 2) outputting a warning audio indicating that the temperature is high via one or more speakers of the surgical system.

19. A method performed by a surgical system, the method comprising: providing an ultrasonic instrument with an electric current below a current threshold at which the instrument causes a blade of the instrument to generate heat; estimating a temperature of the blade based on a resonant frequency of the blade when the current is supplied to the ultrasonic instrument; as well as A notification is displayed on the display based on the estimated temperature of the knife.

20. The method according to claim 19, wherein: The temperature of the knife is estimated without using a temperature sensor.

21. The method according to claim 19, wherein: The blade is arranged to vibrate along a longitudinal axis of the blade to generate the heat, wherein the blade is part of a gripper of the ultrasonic instrument, the gripper also having an articulated arm arranged to rotate about an axis transverse to the longitudinal axis.

22. The method of claim 21 further comprising determining that the gripper is in an open position in which the articulated arm is rotated away from the knife, wherein the temperature is estimated in response to determining that the gripper is in the open position.

23. The method of claim 21 further comprising displaying on the display an endoscopic video of a surgical site within a patient on which a surgical procedure is being performed, wherein the notification is a graphical user interface (GUI) item overlaid on top of the endoscopic video.

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