Method and system for detecting contact of ultrasonic instrument with object

Abstract

A method performed by a surgical system. The method determines a temperature of an end effector of the ultrasonic instrument based on one or more characteristics of the end effector. The method determines that the end effector is in contact with the object, and in response to determining that the end effector is in contact with the object and the temperature is greater than a threshold temperature, presents a notification indicating that the end effector is too hot to be in contact with the object.

Description

Technical Field

[0001] Various aspects of the present disclosure relate generally to surgical systems, and more particularly to surgical systems for detecting whether an ultrasonic instrument is in contact with a subject. 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 a surgical tool is operably attached to the distal end of a robotic arm, and a control system actuates the arm and its attached tool. When the surgeon manipulates a handheld user input device (UID), the end of the tool will simulate its position and orientation motion. 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] The present disclosure provides a laparoscopic surgical system that estimates the temperature of a blade of an ultrasonic instrument during a heating cycle and a cooling cycle of the blade. Specifically, when the instrument is used to dissect tissue, the system can activate the instrument by providing power (e.g., in response to receiving a user input from an operator, such as pressing on a pedal or button) to oscillate the blade of the instrument. While the instrument is active in this "high power" state, the system can determine the temperature of the blade based on one or more characteristics of the instrument (e.g., input voltage, input current, resonant frequency, etc.). After the heating cycle is terminated (e.g., the operator releases the pedal), the system can enter a "low power" state (or cooling cycle) in which the ultrasonic instrument can draw less power (e.g., be provided with less current) to cause the blade to vibrate less than when the instrument is in the high power state. When in this low power state, the instrument may not draw enough power to generate frictional heat (e.g., because the blade vibrates in an excursion range lower than the excursion required to generate heat), but may have enough power to determine one or more characteristics of the instrument, such as the resonant frequency of the blade, which the system can use to estimate the temperature of the ultrasonic instrument when it cools. Thus, the system may provide the operator with (eg, continuous) temperature readings of the ultrasonic instrument between heating cycles and cooling cycles.

[0006] When the blade of an ultrasonic instrument contacts tissue, the temperature estimation of the instrument may be affected. As described herein, the temperature estimation of the blade can be based on the resonant frequency of the blade. However, when the blade touches an object (e.g., tissue), the resonant frequency of the blade may change (e.g., due to the increase in the hardness of the blade when it touches the object). Therefore, the surgical system may not be able to effectively estimate the temperature of the end effector. Therefore, a surgical system is needed to detect whether the end effector of an ultrasonic instrument is in contact with an object to appropriately and effectively estimate the temperature of the end effector.

[0007] In addition, there is a need for a surgical system to notify (alert) an operator of the system when at least a portion of an end effector (e.g., a blade) is in contact with an object. As described herein, once an ultrasonic instrument switches from a heating cycle to a cooling cycle, the blade may be too hot to touch tissue. However, during a surgical operation, the operator may have minimal visibility to the hot end effector. Therefore, the operator may not be able to visually discern whether the end effector is touching anything when the end effector is cooling.

[0008] The present disclosure provides a surgical system that detects and alerts an operator that an ultrasonic instrument is in contact with an object (e.g., tissue). Specifically, the system determines one or more characteristics of an end effector of an ultrasonic instrument (e.g., when the ultrasonic instrument is in a low power state and is cooling). For example, the characteristic may be the impedance and / or resonant frequency of the end effector. The system determines the temperature of the end effector of the ultrasonic instrument based on the characteristic (e.g., by applying the characteristic to a temperature model that produces an estimated temperature as an output). The system determines that the end effector is in contact with an object (such as tissue). For example, the system may determine whether the impedance of the end effector is greater than an impedance threshold. In response to determining that the end effector is in contact with the object and the temperature is greater than a threshold temperature, the system may present (e.g., display) a notification indicating that the end effector is too hot to be in contact with the object. Therefore, the system is able to alert the operator when a hot end effector is (e.g., accidentally) touching an object (such as sensitive tissue).

[0009] In one aspect, determining that the end effector is in contact with the object includes determining that the impedance of the end effector exceeds an impedance threshold relative to a baseline impedance of the end effector. In another aspect, the system determines a plurality of impedances of the end effector over a period of time, determines that a change in the impedance across the plurality of impedances over the period of time is less than a threshold, and in response to determining that the change is less than the threshold, determines a baseline impedance using the plurality of impedances. In some aspects, the baseline impedance is an average impedance across the plurality of impedances.

[0010] In one aspect, the determination of temperature, the determination of the end effector in contact with the object, and the presentation of a notification are performed while the ultrasonic instrument is in a cooling cycle. In another aspect, the end effector is coupled to the handle of the ultrasonic instrument via a shaft, wherein the system determines whether the shaft or the end effector is in contact with the object based on the impedance of the end effector, wherein the end effector is determined to be in contact with the object when the impedance is greater than an impedance threshold. In some aspects, the impedance threshold is a first impedance threshold, and the system further determines that the shaft and the end effector of the ultrasonic instrument are in contact with the object when the impedance is greater than a second impedance threshold, the second impedance threshold is greater than the first impedance threshold, and in response to determining that the shaft and the end effector are in contact with the object, a notification indicating that the end effector and the shaft are in contact with the object is presented.

[0011] One aspect of the present disclosure provides a surgical system including an ultrasonic instrument, wherein the system determines a temperature of a blade of an ultrasonic instrument having a handle coupled to the blade via a shaft, determines whether the blade or the shaft is in contact with an object, and in response to determining that the blade is in contact with the object and the temperature is greater than a temperature threshold, displays a notification on a display of the surgical system.

[0012] In one aspect, the system determines a rate of change in impedance of the blade over a period of time, wherein determining whether the blade or shaft is in contact with the object includes: determining that the blade is in contact with the object in response to determining that the rate of change in impedance of the blade is greater than a threshold rate. In another aspect, the system determines the impedance of the blade, wherein the blade is determined to be in contact with the object in response to the rate of change in impedance of the blade being greater than a threshold rate and the impedance of the blade being greater than a threshold. In some aspects, the system determines whether the blade or shaft is in contact with the object includes: determining that the blade is in contact with the object in response to determining that the impedance of the blade exceeds an impedance threshold relative to a baseline impedance of the blade. In one aspect, the system performs a determination of temperature, a determination of whether the blade or shaft is in contact with the object, and a display of a notification while the ultrasonic instrument is in a cooling cycle. In some aspects, the notification includes an indication that the blade is in contact with the object and includes the temperature of the blade.

[0013] 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

[0014] 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.

[0015] Figure 1 A pictorial view of an exemplary surgical system in a surgical setting is shown.

[0016] Figure 2 A pictorial view of an ultrasonic instrument and generator according to one aspect of the present disclosure is shown.

[0017] Figure 3 Shows Figure 2 An end effector of an ultrasonic instrument.

[0018] Figure 4 is a block diagram of a surgical system according to one aspect.

[0019] Figure 5 is a flow chart of a method for determining whether an end effector of an ultrasonic instrument is in contact with an object.

[0020] Figure 6 is a flow chart of a method for determining whether an end effector and / or shaft of an ultrasonic instrument is in contact with an object.

[0021] Figure 7 is a flow chart of another method for determining whether an end effector and / or shaft of an ultrasonic instrument is in contact with an object.

[0022] Figure 8 Several stages of a display of a surgical system are shown, the display being display of actions performed by an end effector of an ultrasonic instrument and showing notifications based on whether the end effector is in contact with an object.

[0023] Fig. 9 is a flow chart of a method for detecting contact between an end effector of an ultrasonic instrument and an object. DETAILED DESCRIPTION

[0024] 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.

[0025] Figure 1 A pictorial view of an example (e.g., laparoscopic) surgical system (which may be referred to hereinafter as a "system") 1 in a surgical setting is shown. System 1 includes a user console 2, a control tower 3, and one or more surgical robotic arms 4 at a surgical robotic table (surgical table or surgical platform) 5. In one aspect, arm 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.

[0026] 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).

[0027] 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 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 (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).

[0028] 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.

[0029] 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).

[0030] 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.

[0031] 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 .

[0032] 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 .

[0033] 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 the 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 .

[0034] 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.

[0035] 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 operations (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). For example, during a laparoscopic (or endoscopic) surgical procedure, a small incision is made in a patient, and the ultrasonic instrument can be inserted into a cavity of the patient (e.g., insufflating the cavity with a gas), where an end effector can be used by the operator to manipulate tissue and perform surgical operations (e.g., cutting and / or cauterization, etc.). The ultrasonic instrument is coupled to a generator (e.g., via a cable) (as shown), which enables the ultrasonic instrument to operate in one or more power states, as described herein.

[0036] According to aspects of the subject technology, an ultrasonic instrument includes a handle (eg, including a tool driver) 21, a shaft (or cannula) 22, and an end effector 23 loaded into the cannula (eg, which may be coupled to the shaft of the instrument).

[0037] 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, when pulled by one or more fingers of the user while being held, generates a control signal that allows the user to control the end effector of the instrument (and / or control a portion of the surgical system). Specifically, the trigger may be arranged to manipulate the end effector (e.g., by adjusting Figure 3 ). In another aspect, the handle may include one or more inputs for changing the power state of the instrument. More about the power state of the instrument is described herein.

[0038] 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 (e.g., the blade of 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., the 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 (e.g., the blade of 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).

[0039] As described so far, the ultrasonic instrument may include an end effector 23 and a handle (which includes a tool driver) 21. Specifically, the instrument has a handle 21, a shaft 22 coupled to the distal end of the handle, and an end effector 23 coupled to the distal end of the shaft. In this case, the ultrasonic instrument as referred to herein may be an end effector that can be coupled to the handle (e.g., a tool driver coupled to the handle via the shaft 22). In one aspect, the ultrasonic instrument (e.g., the end effector of the ultrasonic instrument) is detachable from the handle (and removably coupled to the handle). In some aspects, the shaft receives and guides the knife (e.g., the shaft of the knife) so as to be coupled to the instrument.

[0040] 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 (e.g., endoscopic, laparoscopic, etc.) tool designed to generate heat.

[0041] 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 4 includes several components that allow the robotic arm to be controlled by an operator. For example, the surgical robotic arm 4 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 the movement of adjacent connectors around certain axes relative to other axes. The plurality of joint modules of the robotic arm 4 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.

[0042] 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).

[0043] Steering Figure 3 , the figure shows Figure 2The end effector 23 of the ultrasonic instrument. Specifically, the figure shows that the end effector is a gripper (or gripping device) including a knife (or end) 30 as a jaw and an articulated arm (or jaw) 31 rotatably coupled to a joint (or robotic wrist) 32, which is coupled to the distal end of the shaft. On the other hand, the end effector 23 (e.g., the joint 32 of the end effector) can be a part of a portion (distal end) of the shaft 22. In one aspect, the gripper (or part of the gripper) is received by the shaft 22. For example, the knife can be received (and extended) through the shaft and arranged to be coupled to a tool driver (e.g., of the handle 21) at (or toward) the proximal end of the shaft. Therefore, as shown in the figure, the knife extends through the shaft (as shown in dashed lines), wherein a portion of the knife (e.g., the end) extends out of the shaft 22 and into the environment. Inside the shaft are two buffers 33, which are arranged between the portion of the knife extending through the shaft and the shaft (e.g., the inside of the shaft). In one aspect, the buffer can be designed to prevent the knife from contacting the inside of the shaft (e.g., when the knife vibrates back and forth). In one aspect, during operation (when the knife oscillates), the knife may (at least partially) contact (e.g., touch) the buffer. On the other hand, when the knife vibrates, the inner portion of the knife may not contact the buffer (at least one of the buffers). On the other hand, the knife may inadvertently contact at least one buffer. For example, during a surgical operation, an object may contact the shaft, causing the inner portion of the knife to shift (or move) toward the buffer (due to the impact of the object), thereby causing the knife to contact the buffer. On the other hand, the shaft may not include a buffer. On the other hand, the knife 30 may be connected to the shaft 22 (e.g., a portion of the shaft 22) (e.g., at the distal end of the shaft). Therefore, the inner portion of the shaft as shown in dotted lines may be connected to the knife 30.

[0044] The articulated arm 31 is rotatably coupled to the shaft 22 (at the joint 32), and the articulated arm is arranged to rotate about a rotation (Z) axis (e.g., in the Z direction). Specifically, the gripper can be arranged to open and close based on the rotational position of the articulated arm about the rotational axis of the joint relative to the knife (and / or the shaft). 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 set between the knife and the articulated arm (e.g., by moving the end effector around the object). When the articulated arm is rotated toward the knife (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 knife 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. In another aspect, the articulated arm 31 can be rotatably coupled to (a portion of) the knife. In one aspect, the knife 30 and the articulated arm can be received by an axis so that the arm (and / or the knife) is coupled to another axis passing through the axis 22.

[0045] 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 (Y) axis of the knife (in the Y direction) 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 axis, as described herein) so that the knife 30 is repeatedly displaced 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.

[0046] As described herein, the knife can generate frictional heat when it vibrates against an object. Specifically, when the gripper squeezes tissue between the two jaws 30 and 31, the knife can come into contact with the tissue and can vibrate against the tissue. When the knife vibrates, the end effector can cut and / or cauterize the tissue, as described herein. In one aspect, the knife 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 knife and the power state of the ultrasonic instrument is described herein.

[0047] As described so far, the end effector 23 can be a gripper. On the other hand, the end effector can be any type of tool that can be designed to be manipulated by an ultrasonic instrument (e.g., the handle 21 of an ultrasonic instrument). For example, the end effector can be an endoscope, a stapler, etc.

[0048] 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 upward against an object (such as tissue) at this offset, friction heat may be generated by the end effector, as described herein. In another aspect, the ultrasonic instrument may 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 may 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 may 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 may 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.

[0049] 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 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 (e.g., when the gripper squeezes the 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.

[0050] 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 of the blade's displacement 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 oscillation at a smaller displacement, the blade may not generate frictional heat (e.g., when in contact with tissue). On the other hand, the blade may generate some frictional heat when in a low-power state and in contact with an object, but 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 dissipates (e.g., within a certain period of time). On the other hand, when in this low-power state, the blade may not vibrate (e.g., the tool driver may not drive the blade).

[0051] 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 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).

[0052] 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.

[0053] 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).

[0054] 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 / pressure sensors) for detecting the presence of an object and / or detecting that the object is in contact with both arms. Specifically, the generator may enter a high power state when it is determined that the gripper is squeezing the object (based on the pressure detected from the sensor being above a threshold). Upon making this determination, the generator may provide a first current to oscillate the knife so as to cause the knife to generate heat. Once the pressure reading drops below a threshold (meaning the object has been released by the gripper), the generator may switch to a low power state.

[0055] 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 end effector of) an ultrasonic instrument when 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, input current, resonant state, resonant frequency, and / or (e.g., mechanical) impedance of an ultrasonic instrument (e.g., an end effector of an 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. Additionally, the system may be configured to determine (at least some of) these characteristics when the instrument is in a low power state (a cooling cycle or cooling period) due to the instrument drawing at least some power. For example, when in a low power state, the generator may determine the resonant frequency and impedance of the end effector (e.g., the blade 30 of the end effector). More information on determining these characteristics is described herein.

[0056] 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.

[0057] As also shown, the generator 25 also includes a display 24, which is arranged to display 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.

[0058] 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 storage device 44, 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.

[0059] Examples of storage devices (e.g., non-transitory machine-readable storage media) may include read-only memory, random access memory, CD-ROM, DVD, magnetic tape, optical data storage devices, flash memory devices, and phase-change memory. Although the storage device is illustrated as being separate from the controller 40, the storage device may be part of the controller (e.g., internal memory).

[0060] 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.

[0061] In one aspect, 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 one or more power states (e.g., in a low power state, where the blade of the end effector is 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 the instrument is in the low power state, such as the resonant frequency of the end effector (e.g., the blade of the end effector). In one aspect, the model can be used to determine the temperature of the blade when the instrument is in a cooling cycle and the end effector is not grasping an object (e.g., when the articulated arm 31 is in an open position). The controller can determine the temperature using one or more temperature (predetermined) models (e.g., which can be stored in the storage device 44), whereby the temperature model (e.g., a polynomial model for the cooling period) can output an estimated temperature of the blade based on (in response to) the resonant frequency as input. For example, the controller may determine a normalized change in resonant frequency (e.g., based on a difference between a (predetermined) baseline resonant frequency and a current resonant frequency reading) and determine one or more model coefficients (based on the resonant frequency at the start of the cooling period and predetermined constants). The controller may estimate the temperature by applying the normalized change in resonant frequency and the coefficients to the model as input, thereby producing a temperature estimate as output.

[0062] In one aspect, when the instrument is in a heating cycle or a cooling cycle, the controller can be configured to determine the temperature of the end effector using one or more (predetermined) models. For example, the controller can be configured to estimate the temperature of the end effector by applying the change in resonant frequency (e.g., the difference between the baseline (or previously determined) resonant frequency and the current resonant frequency of the end effector) to a hysteresis model (stored in the storage device 44) that includes a hysteresis relationship between the change in the resonant frequency of the end effector and the corresponding temperature of the end effector. On the other hand, when the ultrasonic instrument is operating in one or more power states, the controller can use any method to determine the temperature of the end effector.

[0063] In one aspect, (at least some of) the temperature estimation operations may be performed by the controller while the end effector is in a cooling period (e.g., when the instrument is in a low power state). In addition to (or in lieu of) being performed during the cooling period, the temperature estimation operations may be performed while the end effector is "in air," meaning that the blade is not (at least partially) immersed in a liquid and / or not in contact with an object (such as tissue). Specifically, as described herein, during laparoscopic surgery, a cavity may be created within the abdomen of a patient using one or more gases. In this case, the temperature estimation operations may be performed while the end effector (the blade) is within the cavity but not touching tissue and / or liquid (e.g., in an open space within the cavity). In one aspect, the model used by the controller to estimate temperature may be predefined in a controlled environment (e.g., a laboratory) while the blade is in air (e.g., within a patient's body cavity but not touching an object and not immersed in liquid) during a surgical procedure.

[0064] However, when the knife touches an object, the model may be invalid (or inaccurate) in predicting (estimating) the temperature of the knife due to changes in the knife's characteristics (such as the knife's impedance and / or the knife's resonant frequency). For example, when the knife touches an object, due to the increase in the knife's stiffness k, its resonant frequency (or damped natural frequency, ω) may change. d ) increases. Specifically, the natural frequency of attenuation can be considered as:

[0065]

[0066] where γ is the damping ratio, and ω n is the undamped natural frequency of the knife, which can be written as depending on the stiffness of the knife:

[0067]

[0068] Where m is the mass of the blade. In one aspect, m may include the mass of the blade and any object attached to the blade (e.g., residual tissue). The damping ratio may be written as:

[0069]

[0070] where b is the damping on the blade. Therefore, as k increases, ω n increases, so γ decreases, both of which make ω d Increase.

[0071] In addition to the increase in resonant frequency, the impedance of the end effector may also increase due to contact with an object. For example, when the instrument is operating (e.g., in a heating cycle), the system maintains resonance by applying a constant current and adjusting the voltage input to its resonant actuator (e.g., in the handle). If the resonant end effector is subjected to any mechanical resistance (e.g., such as touching tissue), this is manifested as an increase in voltage in the system in response to the increase in load at the blade of the end effector. Similarly, when the ultrasonic instrument is in a cooling cycle, if an object touches the end effector, the voltage may change. Therefore, the system may monitor impedance changes (e.g., which are based on voltage inputs and current inputs) to detect whether the object is in contact with the end effector. Therefore, due to the changes in resonant frequency and impedance caused by the end effector touching the object, the controller may not be able to accurately estimate the temperature using at least some of the model-based methods described herein. Therefore, the controller may be configured to determine whether the end effector of the instrument is touching the object based on the monitored impedance of the instrument, and in response to determine (or estimate) the (new) temperature of the end effector based on this determination. This article describes more about estimating temperature.

[0072] In one aspect, 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 (e.g., in a storage device and / or (internal) memory of the controller) and executed by the controller, and / or may be implemented by hardware logic structures. In one aspect, at least some of the operations performed by the controller may be performed whenever the instrument enters a low-power state (e.g., switches between two or more power states, such as switching between a high-power state to a low-power state). In another aspect, at least some of the operations described herein may be performed when the end effector of the ultrasonic instrument is in an open position, in which the end effector does not grasp tissue in order to perform a surgical task (e.g., cutting, cauterizing, etc.).

[0073] 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.

[0074] Figures 5 to 7 and Fig. 9 Flowcharts of processes 50, 60, 70, and 90, respectively, each of which includes one or more operations that may be performed by the surgical system 1 (e.g., the controller 40 and / or the generator 25 of the surgical system 1). As an example, at least some of the operations may be performed by the generator 25 (e.g., by one or more processors of the generator 25). Therefore, these figures will refer to Figures 2 to 4 . In one aspect, at least some of the operations may be performed when the ultrasonic instrument is in one of the one or more power states described herein (such as a low power state) and / or when the end effector is in an open position. For example, at least some of the operations may be performed when (e.g., whenever) 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 determine the state of the end effector, such as whether it is touching an object. In some aspects, at least some of the operations may be performed periodically (e.g., when the instrument is in a low power state) to determine whether the state of the end effector has changed (e.g., the end effector switches from being in the air to touching an object and then back again).

[0075] Steering Figure 5, which is a flow chart of a process 50 for determining whether an end effector is in contact with an object. The process 50 begins with the controller 40 estimating the temperature of the end effector of the ultrasonic instrument 23 (at box 51). Specifically, the controller may estimate the temperature of the end effector using one or more of the (e.g., predetermined) temperature models, as described herein. For example, the controller may determine one or more characteristics of the end effector, such as a resonant frequency of the end effector, and apply the resonant frequency as an input (a portion) to a predetermined temperature model, which produces a temperature estimate as an output. The controller 40 determines whether the temperature estimate is greater than a temperature threshold (at decision box 52). In one aspect, the temperature threshold may be a predetermined threshold (e.g., determined in a controlled environment such as a laboratory), and if above the predetermined threshold, it is determined that the end effector is too hot to touch an object (such as tissue). If not above the predetermined threshold, which may mean that the end effector is not too hot to touch tissue, the controller may present the temperature estimate of the end effector of the ultrasonic instrument (at box 59). For example, the system 1 may display a pop-up notification on the display 15 (and / or the display 24 of the generator 25) indicating the temperature estimate (e.g., displaying the temperature on the display 15). In another aspect, the notification may include text related to the temperature (e.g., text reading "The end effector is cold"). As another example, the controller 40 may output an audible notification via one or more speakers (e.g., the speaker 43). For example, the audible notification may be one or more sounds (e.g., beeps) indicating the temperature of the end effector. In another aspect, any type of notification related to the temperature of the end effector may be presented.

[0076] However, if the temperature estimate of the end effector is greater than a threshold value (meaning that the end effector is too hot to touch), the controller determines a baseline (or initial) impedance of the end effector (e.g., blade) of the ultrasonic instrument (at box 53). As described herein, the impedance may be a mechanical impedance, which may be determined by the controller using one or more of the (monitored) characteristics of the ultrasonic instrument. For example, the controller may determine an input current of the ultrasonic instrument (e.g., used to drive the blade of the end effector), and determine the mechanical impedance based on these parameters (e.g., based on Ohm's law). In one aspect, the input voltage may be varied to maintain a current that may be set to compensate for changes in impedance. In another aspect, the controller may determine the impedance by applying one or more of the characteristics to a (predetermined) impedance model of the output mechanical impedance (e.g., an electromechanical model of the impedance of the blade). In another aspect, the controller may determine the impedance of the blade using any known method. In one aspect, the baseline impedance may be determined at an initial time t0, such as when the ultrasonic instrument 20 is coupled to (e.g., inserted into) the generator 25. For example, once the instrument is inserted into the generator, the controller may perform one or more diagnostic operations on the instrument (e.g., to determine one or more characteristics, as described herein) to determine whether Imp 基线 In another aspect, the generator may be configured to determine Imp 基线 Thus, based on these operations, the generator may determine a baseline impedance of the blade of the end effector and provide that impedance to the controller.

[0077] In some aspects, the baseline impedance may be determined when the end effector is at (or approximately) room temperature (e.g., a temperature between 20° C. and 25° C.) and / or when the end effector is in air (e.g., when the blade of the end effector is not touching an object). In another aspect, the baseline impedance may be determined once and stored in the storage device 44 of the surgical system 1 (or the memory of the controller 40 of the surgical system 1). For example, the baseline impedance may be determined when the instrument is first coupled to the generator. In another aspect, the baseline impedance may be determined each time an ultrasonic instrument is inserted into the generator. In another aspect, the baseline impedance may be determined at startup of the surgical system (e.g., an ultrasonic instrument of the surgical system) (e.g., during initial power-on). In another aspect, the baseline impedance may be a previously determined impedance (e.g., during a previous execution of process 50).

[0078] In one aspect, the baseline impedance Imp 基线 The baseline impedance may be determined as the impedance level of the end effector when the ultrasonic instrument is in a low power state, the end effector is in an open position, and / or the ultrasonic instrument (e.g., the end effector and shaft of the ultrasonic instrument) is not in contact with any object. In another aspect, the baseline impedance may be determined when the ultrasonic instrument enters a cooling period (e.g., each time). In some aspects, Imp 基线Can be different between different devices. In addition, Imp 基线 It may drift or gradually drop / rise after repeated activation (repeated switching between heating and cooling cycles) throughout a surgical protocol. Since the change in impedance ΔImp (from the baseline impedance level) is what the controller uses to detect whether the end effector is in contact with the object, the controller can be configured to periodically update the baseline impedance value to prevent false object contact detection due to impedance drift or changes due to repeated activation.

[0079] The controller 40 determines the impedance Imp of the end effector (at box 54). For example, the impedance can be a "current" impedance that is determined by the controller during a surgical operation (when the instrument is being used by an operator and is in a cooling cycle). In one aspect, the controller can determine Imp using a similar (or identical) operation as used to determine the baseline impedance. In some aspects, the impedance determined at this time can be determined after the baseline impedance is determined. The controller determines an impedance change (or a change in the impedance of the ultrasonic instrument) ΔImp (at box 55) based on a comparison between the baseline impedance and the determined impedance. Specifically, the impedance change can be the difference between the two impedances, where ΔImp=Imp-Imp 基线 .

[0080] The controller 40 determines whether the impedance change ΔImp is greater than the impedance threshold Th 接触 (At decision box 56). Specifically, the controller determines the relative position of Imp to Imp 基线 Has increased above (exceeded) a certain threshold, which may indicate that the end effector (e.g., the blade of the end effector) is in contact with a (e.g., solid) object (such as tissue). If not (e.g., ΔImp≤Th 接触 ), meaning that the end effector is not in contact with the object, the controller may continue to present an estimate of the temperature of the end effector, as described with respect to block 59. In one aspect, because the temperature of the end effector is high (above the temperature threshold), the controller may present a notification to the operator that the end effector is too hot to touch the object (e.g., displaying “END EFFECTOR IS HOT!” on display 15).

[0081] However, if ΔImp>Th 接触, the controller estimates the temperature of the end effector based on the end effector of the ultrasonic instrument contacting the object (at box 57). In one aspect, the controller may estimate the temperature to be (e.g., approximately) the temperature of the object that the end effector is touching. For example, once the end effector touches the object, the heat within the end effector may be (at least partially) transferred to the object, causing the end effector to cool. Therefore, when touching, both can reach (e.g., approximately) equilibrium, which can be the temperature of the object because the mass of the object can be (significantly) greater than the mass of the end effector (e.g., the end of the knife of the end effector). In some aspects, the controller may be configured to determine what the object is (e.g., based on user input, based on image recognition of one or more images captured by a camera of a surgical system having a field of view including the object, etc.), and estimate the temperature of the object based on the determination (e.g., by performing a table lookup in a data structure (stored in the system) that associates temperature with the object using the determined object). On the other hand, the controller may determine the temperature of the object by other known methods.

[0082] In another aspect, the controller may estimate the temperature of the end effector based on the amount of time the end effector in contact with the object is in contact with the object. For example, when the end effector is touching the object, the temperature may change at a predetermined (e.g., linear) rate. In this case, the controller may estimate the temperature based on the predetermined rate of change from the (raw) estimated temperature (determined at box 51) and the time the end effector has touched the object. In another aspect, the controller may determine the temperature based on a temperature (linear) model that linearly adjusts the temperature based on the temperature estimate (before determining that the end effector is touching the object).

[0083] The controller presents a notification indicating that the end effector is in contact with the object (at box 58). For example, the notification can be a pop-up notification with an image of raindrops and text indicating that the end effector is in contact with the object (e.g., text reading "Tissue Contact" is displayed). On the other hand, the controller can present any type of notification to indicate that the end effector is touching the object. The controller 40 continues to present the temperature estimate (at box 59). For example, the controller can present the temperature estimate along with the notification that the end effector is in contact with the object. On the other hand, the temperature estimate can be presented via a separate notification.

[0084] Some aspects may perform one or more variations of the process 50 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. In one aspect, the controller may perform at least some of the operations one or more times during a power state (e.g., a low power state) so that the surgical system can monitor (estimate) the temperature of the end effector and / or whether the end effector is touching the object while the ultrasonic instrument is operating in this state. In this case, the controller can continuously update the baseline impedance, which the controller can use to continuously determine whether the end effector is in contact.

[0085] In some aspects, the controller may update Imp (e.g., in real time) by continuously (or over a period of time) monitoring the impedance level Imp (e.g., determining the impedance level one or more times over the period of time). 基线 to prevent false triggering of object contact due to displacement. For example, if Imp 基线 is not updated, a large impedance threshold Th may be required 接触 This can reduce the detection sensitivity. However, this will result in increased latency in object contact detection, as a large impedance change will be required to overcome the threshold. By (e.g., continuously) updating Imp 基线 , the system can make Th 接触 Minimizes and therefore provides a faster trigger response to small (or smaller) impedance changes.

[0086] Specifically, to update the baseline impedance, the controller may be configured to determine one or more impedances of the end effector over a period of time, and may be configured to determine whether the impedance change across the one or more impedances over the entire period of time is less than a threshold. Specifically, the controller may determine whether the one or more impedances remain in a stable state for the period of time Δt. If the change in impedance over the entire Δt is less than the threshold ε, the controller may define Imp based on the change in impedance. 基线 In one aspect, in response to determining that the change is less than a threshold, the controller may use one or more impedances to determine Imp 基线 For example, the controller can 基线 Defined as the average impedance across one or more impedances such that if:

[0087] |Imp(t)-Imp(t+Δt)|<∈

[0088] but,

[0089] Imp 基线 =mean(Imp(t),Imp(t+1),…,Imp(t+Δt))

[0090] In some aspects, the controller may update the baseline impedance when the ultrasonic instrument switches from a heating cycle to a cooling cycle. Specifically, the controller may determine that the ultrasonic instrument is in a heating cycle (e.g., the end effector is in a closed position), and in response to determining that the ultrasonic instrument has returned to a cooling cycle (e.g., the end effector is now in an open position and / or in air), the controller may (e.g., begin) monitoring the impedance of the end effector over a period of time to determine a new baseline impedance. In some aspects, the new baseline impedance may be different from the previously determined baseline impedance. This may be due to differences in the monitored impedances, which may be due to various factors (e.g., how long the end effector was in the heating cycle before returning to the cooling cycle, etc.).

[0091] In one aspect, contact of an object with a portion of an ultrasonic instrument may inadvertently increase the level of impedance, depending on the location of the contact. For example, when the contact is on the shaft, the level of impedance may increase depending on the location of the contact, the level of pressure on the shaft, and / or the direction of the pressure applied. When the instrument is inserted into the patient's body through a trocar, forces applied to the shaft may occur frequently during surgical procedures. Specifically, when the instrument shaft passes through the trocar, the trocar may tilt against the shaft of the instrument and apply forces to the shaft of the instrument as the instrument is manipulated within the patient's body during surgical procedures. In one aspect, the increase in impedance due to shaft contact may trigger a false positive for contact detection on the end effector (e.g., the increase in impedance may exceed Th 接触 ). Therefore, to prevent false positives, the surgical system is configured to distinguish between end effector contact and contact by other parts of the ultrasonic instrument, such as shaft contact as described herein. Specifically, the controller can be configured to determine whether the shaft or end effector of the ultrasonic instrument is in contact with the object based on one or more impedances associated with the end effector (e.g., greater than one or more thresholds). Specifically, Figure 6 is a flow chart of a process 60 for determining whether an end effector and / or shaft of an ultrasonic instrument is in contact with a subject.

[0092] In one aspect, as described herein, when the ultrasonic instrument is in one of one or more power states (e.g., a low power state) and / or when the end effector is in an open position, at least some of the operations of the processes described herein may be performed to detect whether the end effector is in contact with the object. In one aspect, one or more operations in one or more of the processes described herein may be similar (or the same) as one or more operations in other processes. For example, Figure 6 The process 60 in includes the operations of blocks 53 to 55, and Figure 7 The process 70 includes Figure 5 The operations of blocks 53 to 56 of process 50 are as follows.

[0093] Now turn to Figure 6 , the process 60 may begin with the controller 40 determining a baseline resonant frequency of an end effector (e.g., a blade of the end effector) of an ultrasonic instrument (at block 61). For example, the controller may determine the baseline resonant RF of the blade at t0. 基线 , as described with respect to the baseline impedance. In one aspect, the controller may determine Imp 基线 (at least partially) simultaneously (or simultaneously) determine RF 基线 Therefore, RF 基线 Available in 基线 The apparatus may be determined under similar conditions (e.g., determined when the instrument is inserted into a generator, determined at room temperature, etc.).

[0094] In some aspects, the generator electronically determines the resonant frequency. 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 may adjust the output voltage (which may be referred to as phase locking) so as to continue to drive at resonance (when the resonant frequency changes with temperature). On the other hand, the controller 40 may adjust the output frequency. On the other hand, other known methods may be used to determine the resonant frequency.

[0095] The controller 40 is configured to determine the (eg, current) resonant frequency RF of the end effector (at block 62). Specifically, the controller may determine RF similarly to the baseline resonant frequency, but may compare the resonant frequency of the end effector to the resonant frequency of the end effector after determining the baseline. 基线 The controller determines the resonant frequency change ΔRF based on the comparison between the baseline resonant frequency and the determined resonant frequency (at block 63). Specifically, the controller may determine the change based on the difference between the frequencies, such that ΔRF=RF-RF 基线 In one aspect, the difference can represent a resonant frequency drift from a baseline (or nominal) resonant frequency to the determined resonant frequency of the blade (or a change therebetween).

[0096] The controller 40 determines the predicted shaft impedance ΔI based on the resonant frequency change 轴 and the predicted end-effector impedance ΔI 端部执行器 (at box 64). Specifically, ΔI 轴 is (e.g., is lower than and / or equal to) the impedance that occurs when a force is applied to the shaft of the ultrasonic instrument (e.g., when an object is in contact with the shaft). On the other hand, ΔI 端部执行器It is the impedance (higher than and / or equal to) of the end effector at which the force can be determined to be applied to the ultrasonic instrument. In one aspect, the predicted end effector impedance is greater than the predicted shaft impedance.

[0097] Specifically, to predict (estimate) the impedance, the controller may apply the change in the resonant frequency to a separate (eg, predefined in a controlled environment) function (eg, a polynomial function), ρ 端部执行器 and ρ 轴 , so that:

[0098] ΔI 端部执行器 =ρ 端部执行器 (ΔRF)

[0099] ΔI 轴 =ρ 轴 (ΔRF)

[0100] In one aspect, these functions can be predefined (e.g., in a controlled environment) based on the behavior of the impedance and resonant frequency of the ultrasonic instrument relative to the location of contact with the instrument. For example, the measured resonant frequency and / or the measured impedance can be different based on whether the force is applied to the end effector (e.g., blade) or to the shaft of the instrument. These changes can be plotted and used to derive functions, each of which describes the relationship between resonant frequency and impedance based on the contact conditions on the ultrasonic instrument (e.g., where the contact occurs).

[0101] The controller 40 determines a baseline impedance Imp of the end effector of the ultrasonic instrument. 基线 (At box 53). The controller determines the (eg, current) impedance of the end effector (at box 54). The controller determines the impedance change ΔImp based on a comparison between the baseline impedance and the determined impedance (at box 55).

[0102] In one aspect, (at least some) operations performed in box 53 and / or box 61 can be omitted from 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 impedance and / or the baseline resonant frequency can be performed once (e.g., during initial power-on). Therefore, process 60 can omit either operation (or both of these operations) in subsequent (at least partial) executions of the process.

[0103] In one aspect, the controller can be configured to determine the impedance (at block 54) and / or the resonant frequency (at block 62) based on the configuration of the ultrasonic instrument. For example, these characteristics can be determined by the surgical system once (or in response to) the end effector of the instrument being in an open position (e.g., while also operating in a low power state). In another aspect, the characteristics can be determined after the controller determines that the end effector is in the open position (either immediately or within a period of time). In another aspect, the controller can determine any of these characteristics once the ultrasonic instrument switches between states, and / or can determine these characteristics periodically after entering a state.

[0104] The controller determines whether the impedance change is greater than (and / or equal to) the predicted shaft impedance (at decision block 65). Specifically, the controller determines whether ΔImp>ΔI 轴 In one aspect, the increase in impedance due to contact between the shaft and the object may be caused by contact between the blade 30 of the instrument and one or more bumpers 33 within the shaft 22. If ΔImp>ΔI 轴 , then it means that the change in impedance is small, which is the result of at least a portion of the shaft 22 of the ultrasonic instrument 20 (e.g., a trocar used during a surgical procedure as described herein) contacting the object. The controller 40 continues to determine that the shaft of the ultrasonic instrument is in contact with the object (at box 100). In one aspect, the surgical system may not alert (notify) the user of such an impact because the shaft of the ultrasonic instrument may not be as hot as the blade (e.g., below a temperature threshold) and may therefore touch the object (such as tissue). On the other hand, the surgical system may alert the operator that the shaft is in contact with the object (e.g., by displaying a pop-up notification on the display 15).

[0105] However, if ΔImp is greater than ΔI 轴 , the controller determines whether the impedance change is greater than the predicted blade impedance (at decision box 66). Specifically, the controller determines whether ΔImp>ΔI 端部执行器 If ΔImp>ΔI 端部执行器, the controller 40 determines that the end effector (e.g., the blade 30) (e.g., a portion of the end effector) is in contact with the object (at box 69). Therefore, the controller determines whether the shaft or the end effector (e.g., the blade of the end effector) is in contact based on the impedance of the end effector, wherein when the impedance (e.g., the change in impedance) is greater than the impedance threshold, the end effector is determined to be in contact with the object. The controller 40 presents a notification that at least a portion of the ultrasonic instrument is in contact with the object (at box 68). Specifically, the controller may display (pop up) a notification (e.g., "The blade is in contact with the object") on the display 15. On the other hand, the controller may replay an audible notification via one or more speakers 43. In some aspects, the controller may present multiple notifications (e.g., display a notification on the display 15 and output an audible notification via the speaker 43).

[0106] However, if ΔImp is greater than ΔI 端部执行器 , the controller determines that the shaft 22 and the end effector 23 of the ultrasonic instrument (e.g., a portion of both the shaft 22 and the end effector 23) are in contact with the object (at box 67). The controller 40 presents a notification that the shaft and the end effector are in contact with the object, such as displaying "Blade and shaft are in contact with the object".

[0107] Figure 7 2 is a flow chart of another process 70 for determining whether the end effector 23 and / or the shaft 22 of the ultrasonic instrument 20 is in contact with an object (e.g., tissue). The process 70 begins with the controller 40 determining a baseline impedance Imp of the end effector (e.g., blade) of the ultrasonic instrument. 基线 (at box 53). The controller determines the impedance Imp of the end effector (at box 54), and determines an impedance change ΔImp based on a comparison between the baseline impedance and the determined impedance (at box 55). The controller determines whether the impedance change is greater than an impedance threshold Th 接触 (At decision box 56).

[0108] If the impedance change is greater than the impedance threshold Th 接触 , the controller determines the rate of impedance change (at box 71). Specifically, the controller determines the rate of impedance change of the blade within a period of time Rate ΔImp (e.g., based on changes in impedance monitored (determined) over a period of time). For example, over the period of time Δt, the controller may determine one or more changes in impedance and store them in memory (e.g., by performing the operations of block 54 one or more times). For example, the rate may be defined as:

[0109]

[0110] The controller determines whether the rate of impedance change is greater than a threshold rate (at decision block 72). Specifically, the controller determines whether RateΔImp >Th 速率 , where the threshold rate may be a predefined threshold (e.g., determined in a controlled environment). ΔImp >Th 速率 , the controller determines that the end effector is in contact with the object (at box 69) and presents a notification indicating that the end effector is in contact with the object (at box 73). Otherwise, if Rate ΔImp <Th 速率 , the controller determines that the shaft of the ultrasonic instrument is in contact with the object (at block 100). In this case, the controller may not notify the operator that the shaft is in contact with the object (e.g., due to the fact that the shaft may not be at a high temperature). On the other hand, the controller may present a notification indicating that the shaft of the ultrasonic instrument is in contact with the object.

[0111] Figure 8 Several stages of a display of a surgical system are shown, the display being displayed showing actions performed by an end effector of an ultrasonic instrument and showing notifications based on whether the end effector is in contact with an object. Specifically, each of the four stages 80 to 83 shows a display 15 being displayed showing an endoscopic video 84 showing the end effector 23 and shaft 22 of the instrument and a portion of an object 85 (e.g., tissue, such as a blood vessel). In one aspect, the display showing the endoscopic video can be a different display of the surgical system, such as the display 24 of the generator 25. In some aspects, the display can show other content, such as other video content and / or a graphical user interface (GUI) of the surgical system, which is displaying one or more UI items (e.g., UI items related to the surgical procedure being performed by the system operator).

[0112] The first stage 80 shows that the end effector 23 is grasping a portion of tissue in order to cut the tissue. At this stage, since the articulated arm 31 is in the closed position, the ultrasonic instrument can be in a heating cycle, thereby squeezing the tissue between the arm 31 and the blade 30. As described herein, when in the closed position and in the heating cycle, the blade can use the friction heat generated by the oscillation of the blade to cut the tissue.

[0113] The second stage 81 shows the result of the end effector 23 cutting the tissue. Specifically, this stage shows that the tissue has been cut into two pieces. In addition, the ultrasonic instrument is in a cooling cycle, wherein the articulated arm is in an open position. Therefore, at this stage, the surgical system 1 (e.g., the controller 40 of the surgical system 1) can perform one or more of the operations described herein to detect whether the instrument is in contact with the object. For example, the controller can be configured to (e.g., once the instrument enters the cooling cycle) begin monitoring the impedance and / or resonant frequency of the end effector, as described herein.

[0114] The third stage 82 shows that the shaft 22 of the ultrasonic instrument is in contact (touching) with a portion of tissue 85. As described herein, the controller can detect that the shaft is touching the object based on the determined impedance of the end effector not exceeding a threshold value. Specifically, the controller can determine that there is a change in impedance (e.g., based on the detected impedance being greater than the baseline impedance), but the change is not greater than a threshold value (e.g., ΔImp< ... 轴 ).

[0115] The fourth stage 83 shows that the blade 30 of the end effector 23 has moved and is now touching the tissue 85. This stage also shows that a notification 86 reading "End Effector Contact" is displayed on the display 15 (e.g., overlaid on top of the endoscope video 84) to notify the operator that the end effector (the blade) is touching an object. As described herein, the controller can present this notification in response to a change in impedance greater than an impedance threshold. On the other hand, the notification can also be displayed in response to the blade of the end effector having a temperature greater than a temperature threshold, thereby alerting the operator that the blade is in contact with the tissue when the blade is too hot to touch the object (such as sensitive tissue).

[0116] Thus, the diagram shows the operator how the controller can (e.g., continuously) perform at least some of the operations of the processes described herein to continuously monitor and update the state of the instrument (e.g., whether the end effector is in contact with the object). Specifically, the controller can continuously monitor a characteristic of the ultrasonic instrument, such as impedance, and use the impedance to determine whether the end effector is in contact with the object. If the end effector is in contact with the object, the operator can be notified, for example, via a pop-up notification (which can also display the temperature of the end effector).

[0117] Fig. 9 is a flow chart of a process 90 for detecting contact of an end effector of an ultrasonic instrument with an object. The process begins with a controller determining a temperature of an end effector of an ultrasonic instrument based on one or more characteristics of the end effector (e.g., a resonant frequency and / or impedance of the end effector) (at box 91). The controller determines that the end effector is in contact with the object (at box 92). Specifically, the controller may determine whether the end effector and / or another portion of the instrument (such as a shaft) is in contact with the object based on one or more of the characteristics. In response to determining that the end effector is in contact with the object (e.g., based on impedance being greater than an impedance threshold) and the temperature being greater than a temperature threshold (which indicates that the end effector is too hot to touch the object 0), a notification indicating that the end effector is too hot to contact the object is presented (displayed) (at box 93). As described herein, the notification may also display the temperature of the end effector (e.g., the blade of the end effector).

[0118] Some aspects may perform one or more variations of one or more processes described herein. For example, specific operations of one or more 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.

[0119] 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, temperature estimation operations, and / or object contact detection operations, as described herein. In other aspects, some of these operations may be performed by specific hardware components that include hardwired logic. These operations may alternatively be performed by any combination of programmed data processing components and fixed hardwired circuit components.

[0120] 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.

[0121] 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 temperature of the end effector of the ultrasonic instrument based on one or more characteristics of the end effector; determining that the end effector is in contact with the object; as well as In response to determining that the end effector is in contact with the object and the temperature is greater than a threshold temperature, presenting a notification indicating that the end effector is too hot to be in contact with the object.

2. The method of claim 1 , wherein determining that the end effector is in contact with the object comprises: It is determined that the impedance of the end effector exceeds an impedance threshold relative to a baseline impedance of the end effector.

3. The method according to claim 2, further comprising: determining a plurality of impedances of the end effector over a period of time; determining that a change in impedance across the plurality of impedances throughout the time period is less than a threshold; as well as In response to determining that the change is less than the threshold, the baseline impedance is determined using the plurality of impedances. The method of claim 3 , wherein the baseline impedance is an average impedance across the plurality of impedances.

5. The method of claim 1, wherein said determining of said temperature, said determining that said end effector is in contact with said object, and said presenting of said notification are performed while said ultrasonic instrument is in a cooling cycle.

6. The method of claim 1 , wherein the end effector is coupled to a handle of the ultrasonic instrument via a shaft, wherein the method further comprises determining whether the shaft or the end effector is in contact with an object based on an impedance of the end effector, wherein the end effector is determined to be in contact with the object when the impedance is greater than an impedance threshold.

7. The method of claim 6, wherein the impedance threshold is a first impedance threshold, wherein the method further comprises: determining that the shaft and the end effector of the ultrasonic instrument are in contact with the object when the impedance is greater than a second impedance threshold, the second impedance threshold being greater than the first impedance threshold; as well as In response to determining that the shaft and the end effector are in contact with the object, presenting the notification indicating that the end effector and the shaft are in contact with the object.

8. 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 a temperature of the end effector based on one or more characteristics of the end effector, determining that the end effector is in contact with the object, and In response to determining that the end effector is in contact with the object and the temperature is greater than a threshold temperature, presenting a notification that the end effector is too hot to be in contact with the object.

9. The surgical system of claim 8, wherein the instructions for determining that the end effector is in contact with the object include instructions for determining that an impedance of the end effector exceeds an impedance threshold relative to a baseline impedance of the end effector.

10. The surgical system of claim 9, wherein the memory has further instructions to: determining a plurality of impedances of the end effector over a period of time; determining that a change in impedance across the plurality of impedances throughout the time period is less than a threshold; as well as In response to determining that the change is less than the threshold, the baseline impedance is determined using the plurality of impedances.

11. The surgical system of claim 10, wherein the baseline impedance is an average impedance across the plurality of impedances.

12. The surgical system of claim 8, wherein the instructions for determining the temperature, the instructions for determining contact of the end effector with the object, and the instructions for presenting the notification are executed while the ultrasonic instrument is in a cooling cycle.

13. The surgical system of claim 8, wherein the end effector is coupled to a handle of the ultrasonic instrument via a shaft, wherein the memory has additional instructions to determine whether the shaft or the end effector is in contact with an object based on an impedance of the end effector, wherein the end effector is determined to be in contact with the object when the impedance is greater than an impedance threshold.

14. The surgical system of claim 13, wherein the impedance threshold is a first impedance threshold, wherein the memory has further instructions to: determining that the shaft and the end effector of the ultrasonic instrument are in contact with the object when the impedance is greater than a second impedance threshold, the second impedance threshold being greater than the first impedance threshold; and In response to determining that the shaft and the end effector are in contact with the object, presenting the notification indicating that the end effector and the shaft are in contact with the object.

15. A method performed by a surgical system, the surgical system comprising an ultrasonic instrument, the method comprising: determining a temperature of a blade of the ultrasonic instrument, the ultrasonic instrument having a handle coupled to the blade via a shaft; determining whether the knife or the shaft is in contact with an object; as well as In response to determining that the blade is in contact with the object and the temperature is greater than a threshold temperature, a notification is displayed on a display of the surgical system.

16. The method according to claim 15, further comprising: A rate of change of impedance of the blade over a time period is determined, wherein determining whether the blade or the shaft is in contact with the object comprises determining that the blade is in contact with the object in response to determining that the rate of change of impedance of the blade is greater than a threshold rate.

17. The method according to claim 16, further comprising: An impedance of the blade is determined, wherein in response to the rate of change of the impedance of the blade being greater than the threshold rate and the impedance of the blade being greater than a threshold, it is determined that the blade is in contact with the object.

18. The method of claim 15, wherein determining whether the knife or the shaft is in contact with the object comprises: Responsive to determining that the impedance of the blade exceeds an impedance threshold relative to a baseline impedance of the blade, it is determined that the blade is in contact with the object.

19. The method of claim 15, wherein determining the temperature, determining whether the blade or the shaft is in contact with the object, and displaying the notification are performed while the ultrasonic instrument is in a cooling cycle.

20. The method of claim 15, wherein the notification includes an indication that the knife is in contact with the object and includes the temperature of the knife.

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