Method and system for detecting that an ultrasonic device is in contact with an object

Abstract

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

Description

Technical Field

[0001] Various aspects of the present disclosure generally relate to surgical systems, and more specifically to surgical systems for detecting whether an ultrasonic instrument is in contact with an object. Other aspects are also described.

Background Art

[0002] Minimally invasive surgery (MIS) such as laparoscopic surgery uses techniques aimed at reducing tissue damage during a surgical procedure. Laparoscopic procedures typically require creating a number of small incisions in a patient, e.g., in the abdomen, and then inserting several surgical tools such as an endoscope, a blade, a gripper, and a needle through these incisions into the patient. Gas is injected into the abdomen, which causes the abdomen to swell, thereby providing more space around the tip of the tool and making it easier for the surgeon to view and manipulate the tissue at the surgical site (via the endoscope). MIS can be performed more quickly and with less fatigue for the surgeon using a surgical robotic system in which the surgical tool is operably attached to the distal end of a robotic arm and a control system actuates the arm and its attached tool. The tip of the tool mimics the movement of the position and orientation of a handheld user input device (UID) when the UID is being operated by a surgeon. The surgical robotic system may have a plurality of surgical arms, and one or more of the plurality of surgical arms may have an attached endoscope and the other surgical arms may have attached surgical instruments for performing a certain surgical action.

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

Summary of the Invention

Means for Solving the Problem

[0004] Some surgical tools used in MIS procedures are ultrasonic instruments that use ultrasonic vibrations at their tips to rapidly generate heat for cutting and cauterizing tissue. The tip may include a blade that reaches a high temperature (e.g., above 300 °C) during a “heating” cycle in which the blade oscillates in contact with a portion of the tissue, thereby generating heat by friction between the blade and the tissue during oscillation. After reaching the high temperature, the blade may be used to incise a portion of the tissue and at the same time seal the remaining tissue. By performing multiple tasks (e.g., cutting for incision, cauterization, etc.), the use of tools during laparoscopic surgery reduces the number of instrument exchanges and instruments during the procedure.

[0005] The present disclosure provides a laparoscopic surgical system that estimates the temperature of a blade of an ultrasonic instrument during heating and cooling cycles of the blade. Specifically, the system may activate the instrument by providing power to oscillate the blade of the instrument (e.g., in response to receiving user input by an operator, such as pressing a petal or a button) when used to incise tissue. While the instrument is operating in this “high power” state, the system may determine the temperature of the blade based on one or more characteristics of the instrument (e.g., input voltage, input current, resonance frequency, etc.). After the heating cycle has ended (e.g., after the operator releases the petal), the system may enter a “low power” state (or cooling cycle), in which the ultrasonic instrument may draw less power to cause less blade vibration than while the instrument was in the high power state (e.g., less current may be supplied). While in this low power state, the instrument may not draw enough power to generate frictional heat (e.g., due to the blade vibrating over a lower range of motion than is required to generate heat), but may have enough power to determine one or more characteristics of the instrument, such as the resonance frequency of the blade, that the system can use to estimate the temperature of the ultrasonic instrument while the ultrasonic instrument is cooling. As a result, the system may provide the operator with (e.g., continuous) temperature readings of the ultrasonic instrument between the heating and cooling cycles.

[0006] The temperature estimate of the ultrasonic device may be affected when the blade of the device is in contact with tissue. As described herein, the temperature estimate of the blade may be based on the resonance frequency of the blade. However, when the blade is in contact with an object (e.g., tissue), the resonance frequency of the blade may change (e.g., due to the increased stiffness of the blade as it contacts the object). As a result, the surgical system may not be able to effectively estimate the temperature of the end effector. Therefore, there is a need for a surgical system that detects whether the end effector of the ultrasonic device is in contact with an object in order to appropriately and effectively estimate the temperature of the end effector.

[0007] Note that when at least a portion of the end effector (e.g., the blade) is in contact with an object, the surgical system needs to notify (warn) the operator of the system. As described herein, when the ultrasonic device switches from a heating cycle to a cooling cycle, the blade may be too hot to contact tissue. However, during surgery, the operator may have minimal visibility of the heated end effector. As a result, the operator may not be able to visually identify whether the end effector is touching something when the end effector cools.

[0008] The present disclosure provides a surgical system that detects when an ultrasonic instrument is in contact with an object (e.g., tissue) and warns an operator. Specifically, the system determines one or more characteristics of an end effector of the ultrasonic instrument (e.g., while in a low-power state and being cooled). For example, the characteristics 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 characteristics (e.g., by applying the characteristics to a temperature model that generates 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 higher than an impedance threshold. In response to determining that the end effector is in contact with the object and that the temperature is higher 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. As a result, the system can warn the operator when the heated end effector is (e.g., inadvertently) 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 several impedances of the end effector over a period of time, determines that a change in impedance over several impedances throughout the period is less than a threshold, and uses several impedances to determine a baseline impedance in response to determining that the change is less than the threshold. In some aspects, the baseline impedance is an average impedance over several.

[0010] In one aspect, determining the temperature, determining that the end effector is in contact with the object, and presenting the 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, and the system determines whether the shaft or the end effector is in contact with the object based on the impedance of the end effector, and the end effector is determined to be in contact with the object when the impedance is higher than an impedance threshold. In some aspects, the impedance threshold is a first impedance threshold, and the system also determines that the shaft and the end effector of the ultrasonic instrument are in contact with the object when the impedance is higher than a second impedance threshold that is higher than the first impedance threshold, and in response to determining that the shaft and the end effector are in contact with the object, presents a notification indicating that the end effector and the shaft are in contact with the object.

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

[0012] In one aspect, the system determines the rate at which the impedance of the blade changes over a period of time, and determining whether the blade or shaft is in contact with an object includes determining that the blade is in contact with the object in response to determining that the rate of change of the impedance of the blade is higher than a threshold rate. In another aspect, the system determines the impedance of the blade and determines that the blade is in contact with the object in response to the rate of change of the impedance of the blade being greater than a threshold rate and the impedance of the blade being higher than a threshold. In some aspects, determining whether the blade or shaft is in contact with an 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 the baseline impedance of the blade. In one aspect, the system determines the temperature, determines whether the blade or shaft is in contact with an object, and displays a notification that occurs 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. The present disclosure is intended to include all systems and methods that can be practiced from all suitable combinations of the various aspects summarized above, as well as those disclosed in the following "Detailed Description of the Invention", particularly those pointed out in the "Claims". Such combinations may have specific advantages not specifically described in the above summary.

Brief Description of the Drawings

[0014] Aspects are illustrated by way of example and not limitation in the figures of the accompanying drawings, in which like reference numerals indicate like elements. Note that references to "an" or "one" aspect in this disclosure are not necessarily to the same aspect, and they mean at least one. Also, for purposes of brevity and reducing the total number of figures, a given figure may be used to illustrate features of more than one aspect, and not all elements in a figure may be required for a given aspect.

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DETAILED DESCRIPTION OF THE INVENTION

[0015] Reference will now be made to the accompanying drawings to describe some aspects of the present disclosure. Whenever the shape, relative position, and other aspects of the parts described in a given aspect are not explicitly defined, the scope of the disclosure herein is not limited only to the parts shown, which are merely for illustrative purposes. Also, although numerous details are described, it is understood that some aspects can be practiced without these details. In other instances, well-known circuits, structures, and techniques are not shown in detail so as not to obscure the understanding of this description. Further, unless the meaning is clearly contrary, all ranges described herein are considered to include the endpoints of each range.

[0016] FIG. 1 shows a depiction of an exemplary (e.g., laparoscopic) surgical system 〈hereinafter, may also be referred to as “system”〉 1 in an operating room. The system 1 includes a user console 2, a control tower 3, and one or more surgical robot arms 4 on a surgical robot table (surgical table or surgical platform) 5. In one aspect, the arm 4 may be mounted on a table or bed on which the patient lies, as shown in the embodiment of FIG. 1. In one aspect, at least some of the arms 4 may be configured differently. For example, at least some of the arms may be mounted on another suitable structural support such as a ceiling, a side wall, or a cart separate from the table. The system 1 may incorporate any number of devices, tools, or accessories used to perform surgery on a patient 6. For example, the system 1 may include one or more surgical tools (instruments) 7 used to perform a surgery (surgical procedure). The surgical tool 7 may be an end effector attached to the distal end of the surgical arm 4 for performing a surgical procedure.

[0017] Each surgical tool 7 may be operated manually, robotically, or both during surgery. For example, the surgical tool 7 may be a tool used to enter, view, or manipulate the internal anatomical structures of the patient 6. In one aspect, the surgical tool 7 is a gripper that can grip the patient's tissue. The surgical tool 7 may be manually controlled by an operator 8 beside the bed or may be robotically controlled via the actuated movement of a surgical robot arm 4 to which the surgical tool is attached. For example, when manually controlled, the operator may (e.g., physically) hold a portion of the tool (e.g., the handle) and manually control the tool by moving the handle and / or pressing one or more input control parts (e.g., buttons) on the tool (e.g., the handle of the tool). In another aspect, when robotically controlled, the surgical system may manipulate a user input based on the surgical tool (e.g., received via the user console 2 as described herein).

[0018] Generally, a remote operator 9, such as a surgeon or other operator, may use the user console 2 to remotely operate the arm 4 and / or the attached surgical tool 7, for example, during teleoperation. The user console 2 may be located in the same operating room as the rest of the system 1, as shown in FIG. 1. However, in other environments, the user console 2 may be located in an adjacent or nearby room, or in a remote location, such as a different building, city, or country. The user console 2 may include one or more components, such as a seat 10, one or more foot-operated controls (or foot pedals) 13, one or more (handheld) user input devices (UIDs) 14, and at least one display 15. The display is configured to display, for example, a view of the surgical site inside the patient 6. The display may be configured to display image data (e.g., still 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 3D (surgical) representations. For example, during a surgical procedure, one or more endoscope cameras may capture image data of the surgical site that the display presents to the user in 3D. In one aspect, the 3D display may be a naked-eye stereoscopic display that provides 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 using glasses (e.g., via active shutter or polarization).

[0019] In another aspect, the display 15 may be configured to be displayed in the last graphical user interface (GUI) that can provide useful and / or interactive content, thereby assisting the user in performing a surgical procedure using one or more instruments within the surgical system 1. For example, some of the displayed content may include image data captured by one or more endoscopic cameras, as described herein. In another aspect, the GUI may include selectable UI items that can cause the system to perform one or more operations when operated by the user. For example, the GUI may include UI items as interactive content for switching control between robotic arms. In one aspect, to interact with the GUI, the system may include an input device, such as a keyboard, mouse, etc. In another aspect, the user may interact with the GUI using the UID 14. For example, the user may operate the UID to navigate through the GUI (e.g., using a cursor), and to make a selection, overlay the cursor on a UI item and operate the UID (e.g., select a control or button). In some aspects, the display may be a touch display screen. In this case, the user may make a selection by navigating and selecting through touching the display. In some aspects, any method may be used to navigate and / or select UI items.

[0020] As shown, the remote operator 9 is sitting on the seat 10 and looking at the user display 15 while operating the foot pedal control 13 and the handheld UID 14 to remotely control one or more of the arm 4 and the surgical tool 7 (attached to the distal end of the arm 4).

[0021] In some variations, the operator 8 beside the bed may also operate the system 1 in the "bed-facing" mode. In this mode, the operator 8 (user) beside the bed is here beside the patient 6 and, for example, operates the robot-driven tool (the end effector attached to the arm 4) held in one hand with a handheld UID14 simultaneously with a manual laparoscopic tool. For example, the left hand of the operator beside the bed may operate the handheld UID to control the robotic components, while the right hand of the operator beside the bed may operate the manual laparoscopic tool. Thus, in these variations, the operator 8 beside the bed may perform both robot-assisted minimally invasive surgery and manual laparoscopic surgery on the patient 6.

[0022] During an exemplary procedure (surgery), the patient 6 is sterilized, prepared, and covered to achieve anesthesia. The initial access to the surgical site may be performed manually, during which the arm of the system 1 is in a storage or retracted configuration (thereby facilitating access to the surgical site). When the access is complete, the initial positioning or preparation of the system 1 including its arm 4 may be performed. Next, the remote operator 9 of the user console 2 operates various end effectors and possibly the imaging system using the foot pedal control 13 and the UID14 to perform the surgery and thereby progress the surgery. Manual assistance may also be provided at the treatment bed or table by a person beside the bed wearing a sterile gown, for example, the operator 8 beside the bed, who may perform tasks such as retracting tissue, performing manual repositioning, and exchanging one or more tools of the robotic arm 4. Also, a non-sterile person may be present to assist the remote operator 9 of the user console 2. When the procedure or surgery is complete, the system 1 and the user console 2 may be configured or set to a state to facilitate postoperative procedures such as cleaning or sterilization and input or printing of medical records via the user console 2.

[0023] In one aspect, the remote operator 9 provides an input command for driving (moving) one or more robot arm actuators 17 (or drive mechanisms) of the system 1 for remote operation by holding and moving the UID 14. The UID 14 can be communicatively coupled to the rest of the system 1, for example, via the console computer system 16 (or host). The UID 14 can generate a spatial state signal corresponding to the movement of the UID 14, for example, the position and orientation of the handheld housing of the UID, and the spatial state signal may be an input signal for controlling the movement of the robot arm actuator 17. The system 1 may control the proportional movement of the actuator 17 using a control signal derived from the spatial state signal. 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, which control how the actuator 17 is energized to drive the segments or links of the arm 4, the movement of the corresponding surgical tool attached to the arm may mimic the movement of the UID 14. Similarly, an interaction between the remote operator 9 and the UID 14 can generate a gripping control signal, for example, to close the jaws of the gripper of the surgical tool 7 to grip the tissue of the patient 6.

[0024] System 1 may include several UIDs 14, in which case respective control signals are generated to control the actuator of each respective arm 4 and the surgical tool (end effector). For example, the remote operator 9 may move the first UID 14 to control the movement of the actuator 17 within the left robotic arm, in which case the actuator responds by operating joints, gears, etc. within that arm 4. Similarly, the movement of the second UID 14 by the remote operator 9 controls the movement of another actuator 17, which in turn drives other joints, gears, etc. of System 1. System 1 may include a right arm 4 on the right side of the patient fixed to the bed or table and a left arm 4 on the left side of the patient. The actuator 17 may include one or more motors, and the motors are controlled to drive the rotation of the joints of the arm 4 to change, for example, the orientation of the endoscope or gripper of the surgical tool 7 attached to that arm with respect to the patient. The movement of several actuators 17 within 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 each respective surgical tool gripper. For example, each UID 14 may generate a respective gripping signal for controlling the movement of an actuator, such as a linear actuator, that opens and closes the jaws of the gripper at the distal end of the surgical tool 7 for gripping tissue within the patient 6.

[0025] In some embodiments, the communication between the surgical robot table 5 and the user console 2 may be through the control tower 3, which may convert user commands received from the user console 2 (more specifically, from the console computer system 16) into robot control commands to be sent to the arm 4 on the surgical table 5. The control tower 3 may also send status and feedback from the surgical table 5 to the user console 2. The communication connections between the surgical table 5, the user console 2, and the control tower 3 may be via wired (e.g., fiber optic) and / or wireless links using any suitable one of various wireless data communication protocols, such as the BLUETOOTH protocol. Any wired connection may optionally be built into the floor and / or walls or ceiling of the operating room. The system 1 may provide video output to one or more displays, including a display in the operating room and a remote display accessible via the Internet or other network. The video output or feed may also be encrypted to ensure privacy, and all or part of the video output may be stored on a server or an electronic medical record system.

[0026] FIG. 2 shows a depiction of an ultrasonic instrument 20 and a generator 25 according to one aspect of the present disclosure. As shown, the ultrasonic instrument is a hand-held laparoscopic tool configured to perform ultrasonic surgery (e.g., tissue cutting and sealing) based on manual operation of the instrument (e.g., of the handle 21) by an operator (e.g., a surgeon). For example, during a laparoscopic (or endoscopic) surgical procedure, a small incision may be made in the patient and the ultrasonic instrument may be inserted into the patient's cavity (e.g., gas may be used for cavity ventilation), and the end effector may be used by the operator to manipulate tissue and perform surgery (e.g., cutting and / or cauterizing, etc.). The ultrasonic instrument is coupled (e.g., via a cable) to a generator (as shown) that enables the ultrasonic instrument to operate in one or more power states as described herein.

[0027] According to an aspect of the present technology, the ultrasonic instrument includes a handle (e.g., including a tool drive unit) 21, a shaft (or cannula) 22, and an end effector 23 that is loaded into the cannula (e.g., can be coupled to the shaft of the instrument).

[0028] The handle 21 is arranged to be held by an operator, enabling the operator to manipulate the ultrasonic instrument (e.g., its end effector 23) 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 enable the operator to control the ultrasonic instrument. For example, the instrument may include a trigger that generates a control signal that enables the user to control the end effector of the instrument (and / or control a part of the surgical system) when pulled by one or more fingers of the user while being gripped. In particular, the trigger may be arranged to operate the end effector (e.g., by adjusting the position of the hinged arm 31 shown in FIG. 3). In another aspect, the handle may include one or more inputs for changing the power state of the instrument. Further description regarding the power state of the instrument is described herein.

[0029] As described herein, the handle may include a tool drive portion arranged to drive the end effector 23 of the ultrasonic instrument. Specifically, the tool drive portion may include a (for example) linear motor or actuator arranged to vibrate (or oscillate) the end effector (blade) at one or more frequencies (for example, a very high (ultrasonic) frequency and a low frequency). In some embodiments, the tool drive portion is configured to vibrate the end effector such that a portion of the end effector (for example, the blade) moves back and forth along one or more axes. Specifically, the tool drive portion may vibrate the end effector over one or more regions of movement, and over each region of movement, the end effector (blade) may be displaced by a different distance from a starting (or beginning) position. Further explanation of how the end effector vibrates is described herein. In another embodiment, the tool drive portion may include an ultrasonic transducer configured to vibrate the end effector in accordance with an input voltage / input current (applied, for example, by the generator 25).

[0030] As previously described, the ultrasonic instrument may include an end effector 23 and a handle (including the tool drive portion) 21. Specifically, the instrument may include a gripping portion 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 that case, the ultrasonic instrument referred to herein may be an end effector that can be coupled (for example) to the handle (via the shaft 22 of the tool drive portion). In one embodiment, the end effector (for example) of the ultrasonic instrument may be separate from the handle (and removably coupled to the handle). In some embodiments, the shaft receives and guides (for example) the blade (shaft) for coupling to the instrument.

[0031] As described herein, the surgical system 1 includes an ultrasonic instrument 20 configured to generate heat based on the vibration of its end effector 23. In another embodiment, the instrument may be any type of energy (e.g., endoscopic, laparoscopic, etc.) tool designed to generate heat.

[0032] As previously described, the ultrasonic instrument 20 may be a hand-held laparoscopic instrument that can be manually held and operated by an operator. In another embodiment, the instrument may be part of a surgical robotic arm. Specifically, the ultrasonic instrument may be coupled to a robotic arm and powered by a generator, as described herein. For example, the ultrasonic instrument may be coupled to the distal end of a robotic arm (e.g., arm 4 of FIG. 1), and the robotic arm includes several components that enable the robotic arm to be controlled by an operator. For example, the surgical robotic arm 4 may include a plurality of links and a plurality of actuation joint modules for actuating the plurality of links relative to each other. The joint modules may include various types such as pitch joints or roll joints, but these may substantially restrict the movement of adjacent links relative to others around a particular axis. The plurality of joint modules of the robotic arm 4 can be actuated to position and orient the ultrasonic instrument for robotic surgery. In one embodiment, the ultrasonic instrument may be coupled to the distal end via a tool drive arranged to actuate the end effector 23 of the instrument.

[0033] When the ultrasonic instrument is coupled to a robotic arm, the movement and operation of the ultrasonic instrument may be performed via one or more user control units (e.g., UID, foot pedal, etc.) coupled to the surgical system. For example, the UID may be arranged to open and close the gripper 23 of the ultrasonic instrument, and / or may be arranged to adjust the (spatial) position in space of the gripper based on the position of the UID, for example.

[0034] Referring to FIG. 3, this figure shows the end effector 23 of the ultrasonic instrument of FIG. 2. Specifically, this figure shows that the end effector is a gripping tool (or gripping device) that includes a blade (or tip) 30 as one jaw and a hinge arm (or jaw) 31 rotatably coupled to a joint (or robotic wrist) 32 coupled to the distal end of the shaft. In another aspect, the end effector 23 (e.g., the joint 32 of the end effector 23) may be part of a portion (distal end) of the shaft 22. In one aspect, the gripping tool (or a part of the gripping tool) is received through the shaft 22. For example, the blade may be received (and extend) through the shaft and is arranged to couple to a tool drive portion (e.g., of the handle 21) at or toward the proximal end of the shaft. Thus, as shown in the figure, the blade extends through the shaft (shown by the dashed line), and a portion of the blade (e.g., the tip) extends out of the shaft 22 and into the environment. Inside the shaft, there are two buffer portions 33 disposed between a portion of the blade extending through the shaft and the shaft (e.g., the inside of the shaft). In one aspect, the buffer portion may be designed to prevent the blade from contacting the inside of the shaft (e.g., while the blade is vibrating back and forth). In one aspect, the blade can (at least partially) contact (e.g., touch) the buffer portion during operation (while the blade is vibrating). In another aspect, the inner portion of the blade may not contact (at least one of) the buffer portions when the blade vibrates. In another aspect, the blade may accidentally contact at least one buffer portion. For example, during surgery, an object may contact the shaft and shift (or move) the inner portion of the blade toward the buffer portion (due to the impact of the object), causing the blade to contact the buffer portion. In another aspect, the shaft may not include a buffer portion. In another aspect, the blade 30 may be coupled to the shaft 22 (a portion of it) (e.g., at the distal end of the shaft). Thus, the inner portion of the shaft shown by the dashed line may be coupled to the blade 30.

[0035] The hinge arm 31 is rotatably coupled to the shaft 22 (at the joint 32) and is arranged to rotate about the rotational (Z) axis (e.g., in the Z direction). Specifically, the gripping portion may be arranged to open and close based on the rotational position of the hinged arm about the axis of rotation of the joint relative to the blade (and / or shaft). For example, the gripper may be arranged to open (or be in the open position) when the hinged arm is rotated away from the blade (e.g., by a threshold distance). While in this position, the end effector may be oriented such that an object, such as tissue, can be disposed between the blade and the hinged arm (e.g., by moving the end effector around the object). The gripper may be closed (or be in the closed position) when the hinged arm rotates towards the blade (e.g., within a threshold distance), whereby the gripper may grip an object between the blade and the hinged arm. As described herein, the hinged arm may be arranged to apply pressure to the gripped object (e.g., compress the object between jaws) in order to grasp the object and / or perform an incision on the object. In another aspect, the hinged arm 31 may be rotatably coupled to a portion of the blade. In one aspect, the blade 30 and the hinged arm may be received through a shaft such that the arm (and / or blade) is coupled to another shaft passing through the shaft 22.

[0036] As described herein, the blade 30 is the jaw of the gripper. In particular, the blade is a jaw that cannot rotate relative to the end effector (e.g., about the Z-axis). The blade may be arranged to vibrate along the longitudinal (Y) axis of the blade (in the Y-axis) to generate heat while the ultrasonic instrument is in a high-power state (or mode). In particular, the blade may be driven to move back and forth (e.g., linearly) along the longitudinal axis of the end effector (and through the cannula as described herein) so as to repeatedly displace the blade 30 at a (e.g., constant) frequency. Specifically, the blade may vibrate (e.g., reciprocate back and forth) over a range of motion (or displacement), in which case the blade moves a distance from the starting position (e.g., forward or away from the end effector) and then returns that distance. In one aspect, the range of motion may be the distance the blade moves from the starting position to the extended position. In another aspect, the range of motion may be the distance the blade moves back and forth.

[0037] As described herein, the blade may generate frictional heat while vibrating in contact with the object. Specifically, the blade may contact and vibrate against the tissue while the gripper is compressing the tissue between the two jaws 30 and 31. When the blade vibrates, the end effector may cut and / or cauterize the tissue as described herein. In one aspect, the blade may vibrate differently (e.g., over different ranges of motion) based on the power state of the ultrasonic instrument (e.g., how much power is being provided). Further description of the vibrating blade and power state of the ultrasonic instrument is described herein.

[0038] As described so far, the end effector 23 may be a gripper. In another aspect, the end effector may be any type of tool that can be designed to be operated by an ultrasonic instrument (e.g., its handle 21). For example, the end effector may be an endoscope, a stapler, etc.

[0039] When returning to FIG. 2, the generator 25 is configured to control (e.g., heat) the end effector 23 in order to control the ultrasonic instrument and provide power to the ultrasonic instrument while the instrument is coupled to and being used by an operator (e.g., during a laparoscopic surgery in which tissue is manipulated and / or one or more surgical tasks are performed on the tissue, such as cutting, sealing, and / or severing, grasping, and incising tissue). In particular, the generator may provide power to the ultrasonic instrument such that the surgical system 1 (e.g., its ultrasonic instrument) can operate in one of one or more power states. For example, the generator may provide power to the instrument such that the ultrasonic instrument is in a “high power” state (or “heating cycle”), in which state the instrument draws power (or current) from the generator (e.g., at a particular voltage) to generate heat in the end effector 23. For example, the generator may provide a (e.g., first) current (or input current) to the handle of the ultrasonic instrument (e.g., the tool drive of the handle), and the ultrasonic instrument may use this current to drive the blade 30 to vibrate (or oscillate) (and at a particular frequency) over a (first) range of motion. Frictional heat may be generated by the end effector as the blade of the end effector is pressed against an object such as tissue and vibrates over this range of motion, as described herein. In another aspect, the ultrasonic instrument may be arranged to operate in a “low power” state (or “cooling cycle”), in which case the ultrasonic instrument no longer draws (sufficient or comparable) power provided by the generator to heat the end effector while the instrument was in the high power state. Specifically, while in this state, the generator may be configured to provide the ultrasonic instrument with less power than the power provided by the generator while the instrument was in the high power state such that the end effector does not generate heat (e.g., when in contact with an object). In particular, the generator may provide the ultrasonic instrument with less current (e.g., a second current) than the (first) current provided by the generator while the instrument was operating in the high power state, and as a result, this does not cause the end effector to generate heat (or heat comparable to when the ultrasonic instrument was in the high power state).As a result, when the ultrasonic instrument transitions from a high-power state to a low-power state, it may begin to cool. Eventually, when maintained in the low-power state, 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, the blade may vibrate at the same frequency in the low-power state as in the high-power state. In another aspect, the blade may vibrate the blade within an allowable frequency range.

[0040] As a result, due to the smaller current provided to the instrument while in the low-power state, the blade of the end effector may be driven by the tool drive unit differently than when the instrument is in the high-power state. In particular, the blade may vibrate over a different range of motion than the range of motion over which the blade vibrates while the instrument is in the high-power state. For example, while in the high-power state, the blade may vibrate over a first (e.g., high) range of motion, which may cause heat to be generated in the blade when pressed against an object, while while in the low-power state, the blade may vibrate over a second (lower) range of motion that may be smaller than the first range of motion (e.g., the blade is displaced less along the longitudinal axis than the first range of motion). In some aspects, the second range of motion may be less than a minimum threshold (e.g., a threshold at which the blade generates heat if the blade vibrates beyond the minimum threshold). In one aspect, the end effector may not generate frictional heat while in contact with an object such as a blood vessel (e.g., while the gripping portion compresses the object) while vibrating over this lower range of motion. In one aspect, the resonant frequency is maintained within an acceptable range regardless of the power state in which the instrument is operating.

[0041] In one aspect, the difference in the vibration of the end effector may be based on the amount of power drawn by the ultrasonic instrument while in different states. For example, the range of motion displaced while the blade is oscillating may be based on (e.g., proportional to) the power drawn by the instrument, such that more power drawn by the instrument may cause the blade to vibrate over a higher range of motion. Conversely, while the ultrasonic instrument is in a low-power state, the instrument may draw less power that causes the blade to vibrate less (than while the instrument is in a low-power state), resulting in the blade potentially not generating frictional heat (e.g., while in contact with tissue). In another aspect, the blade may be in a low-power state and generate some frictional heat while in contact with the object, but less than the heat generated while the instrument is in a high-power state. In this case, the frictional heat generated may not be sufficient to cut and / or seal the tissue. In some aspects, as a result of 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 while the instrument was in a high-power state dissipates (e.g., over a period of time). In another aspect, the blade may not need to vibrate while in this low-power state (e.g., the tool drive may not drive the blade).

[0042] In one aspect, the system may enter (or operate in) at least one of the power states based on a user input (e.g., received by generator 25). In particular, the generator may provide power to the ultrasonic instrument based on receiving a user input to one or more input devices (e.g., an input to a foot pedal, a UID controlled by an operator and communicatively coupled to system 1, and / or an input at the handle 21 of the ultrasonic instrument). The power provided based on the user input may put the ultrasonic instrument in a high-power state in which the ultrasonic instrument draws power from the generator to heat an end effector 23 (e.g., the blade 30 of end effector 23). For example, when the generator receives a (first) user input (e.g., by an operator pulling or pushing a trigger on handle 21), the generator may provide current to the ultrasonic instrument (e.g., the tool drive of the ultrasonic instrument), and the ultrasonic instrument may use the current to drive the end effector as described herein. Thus, when the trigger controls a hinged arm of the end effector, the generator is configured to provide current when the hinged arm is moved (e.g., toward the blade 30 by at least a threshold distance). In another aspect, the system may enter a low-power state based on another (e.g., second) user input (e.g., receiving an input from a different input device coupled to the generator such as a foot pedal).

[0043] In some embodiments, the ultrasonic instrument may be arranged to switch between a high-power state and a low-power state. As described herein, the instrument may operate in the high-power state while the generator is receiving a user input (e.g., the user pulls or presses a trigger on the handle). The instrument may operate in the low-power state in response to the generator not receiving a user input. For example, the ultrasonic instrument may switch from the high-power state to the low-power state in response to the user releasing the trigger on the handle, and the generator may transition between the two states). In one embodiment, as described herein, the instrument may operate in the low-power state while the operator is not actively using the instrument to perform an ultrasonic instrument operation. Specifically, the system may enter the low-power state, but no user input to one or more input devices used by the operator to enter the high-power state is received. However, if the operator desires to actively use the ultrasonic instrument, the ultrasonic instrument may switch to return to the high-power state (e.g., in response to a user input). In another embodiment, the instrument may operate in the low-power state in response to receiving a user input (e.g., the user presses a button on the UID). In another embodiment, the instrument may operate in this state for a period of time. As described herein, the surgical system is configured to determine the temperature of the end effector while in the low-power state (e.g., after switching from the high-power state) to notify the operator of a temperature that may increase because the instrument is operating in the high-power state. If the end effector is cooled to a particular temperature (e.g., below a predefined temperature), at this temperature, since the end effector may not cause thermal damage when in contact with tissue, the generator may stop the instrument by ceasing to provide a lower current.

[0044] In one aspect, the generator may provide different levels of current to heat the blade, which may be based on user input. For example, the generator may receive a first user input (e.g., from one petal coupled to the generator), and in response, provide the maximum (permissible) amount of current to the ultrasonic instrument. Next, the ultrasonic instrument may drive the end effector over the maximum (e.g., predefined) range of motion, which may result in the end effector generating heat at a (first) high temperature. However, when the generator receives a second user input (e.g., from another petal coupled to the generator), the generator may provide a lesser amount of current to the ultrasonic instrument. As a result, the ultrasonic instrument may draw less power and vibrate the end effector over a (second) lower range of motion that may be lower than the first range of motion in which the blade vibrates in response to the first user input. However, this lower range of motion may heat the end effector at a temperature lower than the first temperature of the end effector when the ultrasonic instrument draws more 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, to cut and / or cauterize tissue, more adipose tissue may require the end effector to be at a higher temperature (having the first temperature), while thinner (and less adipose) tissue may require less heat (having the second temperature). In another aspect, the generator may be configured to provide one type of current while in a high-power state (e.g., driving the end effector over the first high range of motion).

[0045] As described herein, the ultrasonic instrument may be activated (e.g., may operate in a high-power state) based on whether the end effector is in a closed position to grasp an object (e.g., a portion of tissue). For example, the ultrasonic instrument may be activated (e.g., by a user) such that the ultrasonic instrument can operate in a high-power state to draw a current sufficient to generate heat in the end effector. In particular, the generator may activate the ultrasonic instrument when it receives a user input to close the end effector (e.g., move the hinged arm 31 within the distance of the blade 30). When a user input for moving the hinged arm is received, the generator may be configured to provide (e.g., sufficient) power to activate the instrument as described herein. In some aspects, the generator may activate the instrument based on a determination that the hinged arm and / or blade is in contact with an object. For example, the ultrasonic instrument may include one or more sensors (e.g., force / pressure sensors) that detect the presence of an object and / or detect that the object is in contact with both arms. In particular, the generator may enter a high-power state when it is determined that the gripper is compressing the object (based on the pressure detected by the sensor exceeding a threshold). When this decision is made, the generator may provide a first current to oscillate the blade to generate heat in the blade. When the pressure reading drops below the threshold (which means the object has been released by the gripper), the generator may switch to a low-power state.

[0046] In one aspect, a surgical system (e.g., its generator) may be configured to determine one or more characteristics of an ultrasonic instrument (of its end effector) while the instrument is in one or more power states. For example, the generator may be configured to track (or monitor) characteristics such as input voltage, input current, resonance state, resonance frequency, and / or (for example) the (e.g., mechanical) impedance of the ultrasonic instrument (of its end effector). In one aspect, the generator may be configured to monitor at least some of these characteristics of the instrument while the instrument is operating in a high-power state. Note that the system may also be configured to determine (at least some of) these characteristics while the instrument is in a low-power state (cooling cycle or cooling period) due to the instrument drawing at least some power. For example, the generator may determine the resonance frequency and impedance of the end effector (e.g., blade 30 of the end effector) while in the low-power state. Further determination of these characteristics is described herein.

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

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

[0049] 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 may be part of an electronic device of the system such as a stand-alone speaker or a user console 2). In one aspect, the system may include more or fewer elements, such as having two or more displays and / or not having a speaker.

[0050] Examples of storage devices (e.g., non-transitory machine-readable storage media) may include read-only memory, random access memory, CD-ROMs, DVDs, magnetic tapes, optical data storage devices, flash memory devices, and phase change memories. Although shown as separate from the controller 40, the storage device may be part of the controller (e.g., internal memory of the controller).

[0051] In some aspects, the controller 40 may be a dedicated processor such as an application specific integrated circuit (ASIC), a general purpose microprocessor, a field programmable gate array (FPGA), a digital signal controller, or a set of hardware logic structures (e.g., filters, arithmetic logic units, and dedicated state machines). In one aspect, the controller may be part of an electronic device such as the console computer system 16, the control tower 3, and / or the user console 2. Although illustrated as a single component, in one aspect, the controller may include one or more electronic components (e.g., processors, memories, etc.) communicatively coupled across the above devices (e.g., communicating via a wireless computer network) on a single electronic device (such as the console computer 16). In some aspects, the controller may be part of a separate device, such as part of a remote server communicating with one or more electronic devices. In another aspect, the controller may be part of the generator 25 (e.g., at least partially integrated within the generator 25). In that case, at least some of the other elements (e.g., speakers and displays) may also be part of the generator (integrated within the generator). As a result, at least some of the operations performed by the controller described herein may be performed by the generator.

[0052] In one aspect, the controller is configured to perform a temperature estimation operation of the surgical system 1 to determine (e.g., in real time) the temperature of (e.g., the end effector of the ultrasonic instrument) while the instrument is in one or more power states (e.g., a low power state in which 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 while the instrument is in a low power state, such as the resonant frequency of the end effector (e.g., its blade). In one aspect, the model may be used to determine the temperature of the blade while the instrument is in a cooling cycle and the end effector is not gripping an object (e.g., while the hinge arm 31 is in the open position). The controller may determine the temperature using one or more (predetermined) models of temperature (e.g., which may be stored in the storage device 44), whereby the temperature model (e.g., a polynomial model for the cooling period) may output the estimated temperature of the blade as an input based on the resonant frequency (in response thereto). For example, the controller may determine a normalized change in the resonant frequency (e.g., based on the difference between a (predetermined) baseline resonant frequency and the current resonant frequency reading), and determine one or more model coefficients (based on the resonant frequency at the start of the cooling period and a predetermined constant). The controller may estimate the temperature by applying the normalized change in the resonant frequency and the coefficients as inputs to the model, and the model generates the temperature estimate as an output.

[0053] In one aspect, the controller may be configured to determine the temperature of the end effector using one or more (predetermined) models while the instrument is in either a heating cycle or a cooling cycle. For example, the controller may apply a change in the resonance frequency of the end effector (e.g., the difference between a baseline (or previously determined) resonance frequency and the current resonance frequency of the end effector) to a hysteresis model (stored in the memory device 44) that includes a hysteresis relationship between the change in the resonance frequency of the end effector and the corresponding temperature of the end effector to estimate the temperature of the end effector. In another aspect, the controller may use any method to determine the temperature of the end effector while the ultrasonic instrument is operating in one or more power states. [[ID=!]]

[0054] In one aspect, (at least some of) the operations of the temperature estimation operation may be performed by the controller while the end effector is in a cooling period (e.g., while the instrument is in a low power state). In addition to (or instead of) being performed during the cooling period, the temperature estimation operation may be performed while the end effector is "in air", which means that the blade is not (at least partially) immersed in a liquid and / or not in contact with an object such as tissue. In particular, as described herein, during laparoscopic surgery, one or more gases may be used to create a cavity within the patient's abdomen. In that case, the temperature estimation operation may be performed while the end effector (blade) is within the cavity but not in contact with tissue and / or liquid (e.g., in the open space within the cavity). In one aspect, the model used by the controller to estimate the temperature may be predefined in a controlled environment (e.g., a laboratory) while the blade is in air (e.g., within the patient cavity but not in contact with an object and not immersed in a liquid) during a surgical procedure.

[0055] However, when the blade contacts the object, the model may be ineffective (or inaccurate) in predicting (estimating) the temperature of the blade due to changes in the characteristics of the blade, such as the impedance of the blade and / or the resonant frequency of the blade. For example, when the blade is in contact with the object, due to an increase in the stiffness k of the blade, its resonant frequency or the damped natural frequency, ω d increases. In particular, the damped natural frequency can be seen as follows

[0056]

Number

[0057]

Number

[0058]

Number

[0059] In addition to the resonant frequency increasing, the impedance of the end effector may also increase as a result of contact with the object. For example, while the instrument is operating (e.g., during a heating cycle), the system applies a constant current to its resonant actuator (e.g., within the handle) and adjusts the voltage input to maintain resonance. When the resonating end effector experiences some mechanical resistance (e.g., contacting tissue), this appears as an increase in voltage within the system in response to the increased load on the blade of the end effector. Similarly, the voltage may change when the object touches the end effector while the ultrasonic instrument is in a cooling cycle. As a result, the system may monitor for impedance changes (e.g., based on voltage input and current input) to detect whether the object is in contact with the end effector. Thus, due to changes in the resonant frequency and impedance caused by the end effector contacting the object, the controller may not be able to accurately estimate the temperature using at least some of the model-based methods described herein. As a result, the controller may be configured to determine whether the end effector of the instrument is in contact with the object based on the monitored impedance of the instrument, and, accordingly, determine (or estimate) the (new) temperature of the end effector based on that determination. Further explanation regarding estimating the temperature is described herein.

[0060] In one aspect, at least some of the operations performed by the controller may be stored in the memory of the surgical system (e.g., the storage device and / or (internal) memory of the controller) and implemented by software (e.g., as instructions) executed by the controller and / or may be implemented by a hardware logic structure. In one aspect, at least some of the operations performed by the controller may be performed each time the instrument enters a low-power state (e.g., switches between two or more power states such as switching from a high-power state to a low-power state). In another aspect, at least some of the operations described herein may be performed while the end effector of the ultrasonic instrument is in an open position where the end effector is not grasping tissue to perform a surgical task (e.g., cutting, cauterizing, etc.).

[0061] As shown, the generator may receive a user input (e.g., via one or more electronic devices coupled to the generator) to cause the generator to perform one or more operations. For example, the user input may be received via the ultrasonic instrument (e.g., when the user pulls the trigger of the 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.

[0062] Figures 5-7 and 9 are flowcharts of processes 50, 60, 70, and 90, respectively, each process including one or more operations that may be performed by a surgical system 1 (e.g., controller 40 and / or generator 25 of surgical system 1). As another example, at least some of the operations may be performed by generator 25 (e.g., by one or more of its processors). Accordingly, these figures are described with reference to FIGS. 2-4. In one aspect, at least some of these operations may be performed while the ultrasonic instrument is in one of one or more power states described herein, such as a low power state, and / or while the end effector is in an open position. For example, as described herein, at least some operations may be performed when the ultrasonic instrument switches from a high power state to a low power state (e.g., each time), which may be based on user input. In that case, the surgical system may perform these operations to determine a state of the end effector, such as whether the end effector is touching an object. In some aspects, at least some of the operations may be performed periodically (e.g., while the instrument is in a low power state) to determine whether the status of the end effector changes (e.g., switches from being in the air to contacting an object and then back again).

[0063] Referring to FIG. 5, this is a flowchart of a process 50 for determining whether an end effector is in contact with an object. Process 50 begins with the controller 40 estimating the temperature of the end effector of the ultrasonic instrument 23 (block 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 the resonant frequency of the end effector, and apply the resonant frequency as (part of) an input to a predetermined temperature model, which generates a temperature estimate as an output. The controller 40 determines whether the temperature estimate is higher than a temperature threshold (decision block 52). In one aspect, the temperature threshold may be a predetermined threshold (e.g., determined in a controlled environment such as a laboratory), and exceeding it may result in a determination that the end effector is too hot to touch an object such as tissue. Otherwise, this may mean that the end effector is not hot enough to touch the tissue, and the controller may present the temperature estimate of the end effector of the ultrasonic instrument (block 59). For example, system 1 may display a pop-up notification indicating the temperature estimate on the display 15 (and / or the display 24 of the generator 25) (e.g., display the temperature on the display 15). In another aspect, the notification may include text regarding the temperature (e.g., the text "The End Effector is Cool"). As another example, the controller 40 may output an audible notification through one or more speakers (e.g., speaker 43). For example, the audible notification may be one or more sounds (e.g., beep sounds) indicating the temperature of the end effector. In another aspect, any type of notification regarding the temperature of the end effector may be presented.

[0064] However, when the estimated temperature of the end effector is higher than the threshold value (which means that the end effector is too hot to be touched), the controller determines the reference (or initial) impedance of the end effector (e.g., the blade) of the ultrasonic instrument (block 53). As described herein, the impedance may be a mechanical impedance that can be determined by the controller using one or more of the (monitored) characteristics of the ultrasonic instrument. For example, the controller may determine the 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 vary to maintain a current that is set to compensate for changes in the impedance. In another aspect, the controller may determine the impedance by applying one or more of the characteristics to a (predetermined) impedance model (e.g., an electromechanical model of the blade impedance) that outputs the mechanical impedance. In another aspect, the controller may use any well-known method to determine the impedance of the blade. In one aspect, the baseline impedance may be determined at an initial time t0, such as when the ultrasonic instrument 20 is coupled (e.g., plugged in) to the generator 25. For example, when the instrument is plugged into the generator, the controller may determine Imp Baseline by performing one or more diagnostic operations on the instrument. In another aspect, the generator may be configured to determine Imp Baseline . Thus, based on the operation, the generator may determine the baseline impedance of the blade of the end effector and provide that impedance to the controller.

[0065] In some embodiments, this baseline impedance may be determined while the end effector is at room temperature (or near room temperature), e.g., between 20-25° C., and / or while the end effector is in air, e.g., while the blades of the end effector are not in contact with an object. In another embodiment, the baseline impedance may be determined once and stored in the memory device 44 of the surgical system 1 (or the memory of the controller 40). For example, the baseline impedance may be determined when the instrument is first coupled to the generator. In another embodiment, the baseline impedance may be determined each time the ultrasonic instrument is plugged into the generator. In another embodiment, the baseline impedance may be determined at the start of the surgical system (e.g., during initial power-up), e.g., of the ultrasonic instrument by the surgical system. In another embodiment, the baseline impedance may be an impedance determined previously, e.g., during a previous implementation of process 50).

[0066] In one embodiment, the baseline impedance Imp Baseline is determined to be 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 the shaft of the ultrasonic instrument) is not in contact with any object. In another embodiment, the baseline impedance may be determined (e.g., each time) when the ultrasonic instrument enters a cooling period. In some embodiments, Imp Baseline may vary between different devices. Further, Imp BaselineAfter repeated activations (switching repeated between a heating cycle and a cooling cycle) throughout the surgical procedure, it may drift or step down / step up. Since ΔImp, which is a change in impedance (from the baseline impedance level), is what the controller uses to detect whether the end effector is in contact with the object, the controller may be configured to periodically update the baseline impedance value to prevent false object contact detection due to impedance drift or changes due to repeated activations.

[0067] The controller 40 determines Imp, which is the impedance of the end effector (at block 54). For example, the impedance may be the "current" impedance determined by the controller during the surgical procedure (while the instrument is being used by the operator and is in the cooling cycle). In one aspect, the controller may determine Imp using the same (or the same) operation as that used to determine the baseline impedance. In some aspects, the impedance determined at this point may be determined after the baseline impedance. The controller determines a change in impedance (or a change in the impedance of the ultrasonic instrument) ΔImp based on a comparison between the baseline impedance and the determined impedance (block 55). Specifically, the change in impedance may be the difference between two impedances, where ΔImp = Imp - Imp Baseline is.

[0068] The controller 40 determines whether the change in impedance ΔImp is higher than the impedance threshold Th Contact (decision block 56). Specifically, the controller determines whether Imp is Imp BaselineIt is determined whether it has increased above a specific threshold value, which may indicate that the end effector (e.g., its blade) is in contact with an object such as tissue (e.g., a solid). If not (e.g., ΔImp≦(Th Contact ), it means that the end effector is not in contact with the object, and the controller may proceed to present an estimated temperature of the end effector as described with respect to block 59. In one aspect, since the temperature of the end effector is high (above the temperature threshold), the controller may present a notification warning the operator that the end effector is too hot to touch the object (e.g., display "End Effector is Hot!" on the display 15).

[0069] However, when ΔImp>Th Contact is the case, the controller estimates the temperature of the end effector of the ultrasonic device based on the fact that the end effector is in contact with the object (block 57). In one aspect, the controller may estimate the temperature to be (substantially) the temperature of the object with which the end effector is in contact. For example, when the end effector contacts the object, heat in the end effector may be (at least partially) transferred to the object, and the end effector may be cooled. As a result, during contact, if the mass of the object is (significantly) larger than the mass of the end effector (e.g., the tip of the blade of the end effector), the two may reach an (approximate) equilibrium that can be the temperature of the object. In some aspects, the controller determines 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 is configured to estimate the temperature of the object based on the determination (e.g., by performing a table lookup into a data structure associating the temperature with the object (stored in the system) using the determined object). In another aspect, the controller may determine the temperature of the object by other well-known methods.

[0070] In another aspect, the controller may estimate the temperature of the end effector in contact with the object based on the amount of time it has been in contact with the object. For example, when the end effector is in contact with the object, the temperature may change at a predetermined (e.g., linear) rate of change. In this case, the controller may estimate the temperature based on the predetermined rate of change from the (original) estimated temperature (determined at block 51) and the amount of time the end effector has been in contact with the object. In another aspect, the controller may determine the temperature based on a temperature (linear) model that linearly adjusts the temperature based on a temperature estimate (before determining that the end effector is in contact with the object).

[0071] The controller presents a notification (block 58) indicating that the end effector is in contact with the object. For example, the notification may be a pop-up notification having an image of a raindrop and text indicating that the end effector is in contact with the object (e.g., text reading "Tissue Contact"). In another aspect, the controller may present any type of notification indicating that the end effector is in contact with the object. The controller 40 proceeds to present the temperature estimate (block 59). For example, the controller may present the temperature estimate along with a notification that the end effector is in contact with the object. In another aspect, the temperature estimate may be presented by a separate notification.

[0072] Some embodiments may implement one or more variations to the process 50 described herein. For example, certain operations of the process may not be performed in the exact order illustrated and described. Certain operations may not be performed in one continuous series of operations, and different specific operations may be performed in different manners. 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 in contact with an object between power states (e.g., the low power state). In that case, the controller may continuously update a baseline impedance that the controller can use to continuously determine whether the end effector is in contact.

[0073] In some aspects, the controller may (e.g., in real time) update Imp by continuously (or within a period of time) monitoring (e.g., determining the level of impedance one or more times over a period of time) the impedance level Imp to prevent false triggering of object contact due to a shift. Baseline For example, when Imp Baseline is not updated, a high impedance threshold Th Contact may be required to reduce the detection sensitivity. However, this leads to an increase in the waiting time in object contact detection because a large impedance change is required to overcome the threshold. By updating Imp Baseline continuously (e.g.), the system may minimize Th Contact and thus provide a faster trigger response for small (or smaller) impedance changes.

[0074] 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 a change in impedance over the one or more impedances over the entire period is less than a threshold. In particular, the controller may determine whether one or more impedances remain within a steady state over a period Δt. When the change Δt in impedance is below a threshold ε, the controller may define Imp Baseline based on the change in impedance. In one aspect, in response to determining that the change is less than the threshold, the controller may use the one or more impedances to determine Imp Baseline . For example, the controller may define Imp Baseline as the average impedance over the one or more impedances, in which case, |Imp(t)-Imp(t + Δt)| < ∈ then, Imp Baseline = average(Imp(t), Imp(t + 1),..., Imp(t + Δt)).

[0075] In some aspects, the controller may update the baseline impedance when the ultrasonic instrument switches from a heating cycle to a cooling cycle. In particular, 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 currently in an open position and / or in air), the controller may monitor (e.g., start) 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 impedance resulting from various factors (e.g., the length of time the end effector was in a heating cycle before returning to a cooling cycle, etc.).

[0076] In one aspect, the contact between the object and a portion of the ultrasonic instrument may inadvertently increase the impedance level depending on the location of the contact. For example, when the contact is on the shaft, the impedance level may increase depending on the location of the contact, the level of pressure on the shaft, and / or the direction of the applied pressure. The force applied to the shaft may occur frequently during a surgical procedure when the instrument is inserted into the patient's body through a trocar. In particular, when the instrument shaft passes through the trocar while the instrument is being manipulated inside the patient's body during a surgical procedure, the trocar may lean against the instrument shaft and exert a force on the instrument shaft. In one aspect, the increase in impedance due to shaft contact may trigger a false positive in contact detection on the end effector (e.g., the increase in impedance may exceed Th Contact ). Thus, to prevent false positives, the surgical system is configured to distinguish between the end effector contact and the contacts of other portions of the ultrasonic instrument, such as the shaft contacts described herein. In particular, the controller may 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., higher than one or more threshold values). In particular, FIG. 6 is a flowchart of a process 60 for determining whether the end effector and / or shaft of the ultrasonic instrument is in contact with the object.

[0077] In one aspect, at least some of the operations of the processes described herein may be performed while the ultrasonic instrument is in one of one or more power states (e.g., a low power state) and / or while the end effector is in an open position to detect whether the end effector is in contact with the object, as described herein. In one aspect, one or more operations of one or more of the processes described herein may be similar (or the same) as one or more operations in other processes. For example, process 60 of FIG. 6 includes operations of blocks 53-55, and process 70 of FIG. 7 includes operations of blocks 53-56 of process 50 of FIG. 5.

[0078] Referring now to FIG. 6, process 60 may be initiated by the controller 40 determining the baseline resonance frequency of the end effector (e.g., blade) of the ultrasonic instrument (block 61). For example, the controller may determine the baseline resonance RF of the blade at t0, as described with respect to the baseline impedance. Baseline In one aspect, the controller may determine (at least in part) the RF Baseline simultaneously with (or at the same time as) the determination of Imp Baseline . Thus, the RF Baseline may be determined under conditions similar to those of Imp Baseline (e.g., determined when the instrument is plugged into the generator, determined at room temperature, etc.).

[0079] In some embodiments, the generator electronically determines the resonance frequency. For example, the generator may detect 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., the tool drive unit) may include an ultrasonic transducer configured to vibrate the blade according to the input voltage and current waveforms. The frequency that generates a phase angle difference of a threshold (e.g., zero) is the resonance frequency. In one embodiment, the generator may continue to drive the ultrasonic transducer in a resonant state and adjust the output voltage (sometimes called phase lock) to continue to drive in a resonant state (since the resonance frequency changes with temperature changes). In another embodiment, the controller 40 may adjust the output frequency. In another embodiment, other well-known methods may be used to determine the resonance frequency.

[0080] The controller 40 is configured to determine the (e.g., current) resonance frequency RF of the end effector (block 62). Specifically, the controller may determine RF in the same manner as the baseline resonance frequency, but RF may be determined after the baseline with respect to Imp in a manner similar to Imp. The controller determines a resonance frequency change ΔRF based on a comparison of the baseline resonance frequency and the determined resonance frequency (block 63). Specifically, the controller may determine the change based on the difference between the frequencies such that ΔRF = RF - RF Baseline Baseline Baseline and the difference may represent the resonance frequency drift (or change therebetween) from the baseline (or nominal) resonance frequency of the blade to the determined resonance frequency.

[0081] Based on the resonance frequency change, the controller 40 determines a predicted shaft impedance ΔI Shaft and a predicted end effector impedance ΔI End Effector Shaft Shaftis the impedance that occurs (e.g., less than and / or equal to) when a force is applied to the shaft of the ultrasonic instrument (e.g., when an object contacts the shaft). On the other hand, ΔI End Effector is the impedance at which it can be determined that a force is being applied to the end effector of the ultrasonic instrument (greater than and / or equal to). In one aspect, the predicted end effector impedance is higher than the predicted shaft impedance.

[0082] Specifically, to predict (estimate) the impedance, the controller applies a change in the resonant frequency to separate ρ End Effector and ρ Shaft functions, whereby ΔI End Effector = ρ End Effector (ΔRF) ΔI Shaft = ρ Shaft (ΔRF).

[0083] In one aspect, these functions may be predefined based on the behavior of the impedance and resonant frequency of the ultrasonic instrument with respect to the location of contact with the instrument (e.g., in a controlled environment). For example, the measured resonant frequency and / or the measured impedance may vary based on whether a force is being applied to the end effector (e.g., the blade) or the shaft of the instrument. These changes are plotted and may be used to derive functions that each describe the relationship between the resonant frequency and the impedance based on the contact state (e.g., where the contact occurs) on the ultrasonic instrument.

[0084] The controller 40 is the baseline impedance Imp of the end effector of the ultrasonic instrument BaselineDetermine (block 53). The controller determines the (e.g., current) impedance Imp of the end effector (block 54). The controller determines an impedance change ΔImp based on a comparison between the baseline impedance and the determined impedance (block 55).

[0085] In one aspect, the (at least some of the) operations performed at block 53 and / or block 61 can be omitted from process 60. For example, as described herein, at least some of these operations may be performed each time the ultrasonic instrument enters a low power state. However, the determination of the baseline impedance and / or the baseline resonance frequency may, in some aspects, be performed only once (e.g., at initial power - on). As a result, process 60 can omit any (or both) of these operations in subsequent (at least partial) implementations of this process.

[0086] In one aspect, the controller may be configured to determine the impedance (at block 54) and / or the resonance frequency (at block 62) based on the configuration of the ultrasonic instrument. For example, these characteristics may be determined by (or in response to) the surgical system when the end effector of the instrument is in the open position (e.g., when operating even in a low - power state). In another aspect, the characteristics may be determined after (or immediately after or within that time) the controller determines that the end effector is in the open position. In another aspect, the controller may determine any of these characteristics when the ultrasonic instrument switches between states and / or may periodically determine the characteristics after entering a state.

[0087] The controller determines whether the impedance change is higher (and / or equal) than a predicted shaft impedance (decision block 65). Specifically, ΔImp>ΔI ShaftDetermine whether it is. In one aspect, the increase in impedance due to the shaft contacting the object may be due to the blade 30 of the instrument contacting one or more buffer portions 33 within the shaft 22. If not, 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 contacting the object (e.g., a trocar used during a surgical procedure as described herein). The controller 40 then determines that the shaft of the ultrasonic instrument is in contact with the object (block 100). In one aspect, the surgical system may not warn (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 can thus contact an object such as tissue. In another aspect, the surgical system may warn the operator that the shaft is in contact with the object (e.g., by displaying a pop-up notification on the display 15).

[0088] However, when ΔImp is higher than ΔI Shaft In the case where it is higher, the controller determines whether the impedance change is higher than the predicted blade impedance (decision block 66). In particular, the controller determines that ΔImp > ΔI End EffectorDetermine whether it is so. If not, the controller 40 determines that (for example) the end effector (for example, the blade 30) (a part of it) is in contact with the object (block 69). Therefore, the controller determines whether the shaft or the end effector (for example, the blade of the end effector) is in contact based on the impedance of the end effector, and when the impedance (for example, the change in impedance) is higher than the impedance threshold, it is determined that the end effector is in contact with the object. The controller 40 presents a notification that at least a part of the ultrasonic device is in contact with the object (block 68). In particular, the controller may display a (pop-up) notification (for example, "Blade in Contact with an Object") on the display 15. In another aspect, the controller may reproduce an audible notification via one or more speakers 43. In some aspects, the controller may present multiple notifications (for example, display a notification on the display 15 and output an audible notification via the speaker 43).

[0089] However, when ΔImp is higher than ΔI End Effector the controller determines that both the shaft 22 and the end effector 23 (parts of both) of the ultrasonic device are in contact with the object (block 67). The controller 40 notifies that the shaft and the end effector are in contact with the object, such as by displaying "Blade and Shaft are in Contact with an Object".

[0090] Figure 7 is a flowchart of another process 70 for determining whether the end effector 23 and / or the shaft 22 of the ultrasonic device 20 is in contact with an object (for example, tissue). Process 70 is such that the controller 40 determines the baseline impedance Imp of the end effector (for example, the blade) of the ultrasonic device BaselineIt starts by determining (block 53). The controller determines the impedance Imp of the end effector (in block 54), and determines the impedance change ΔImp based on the comparison between the baseline impedance and the determined impedance (in block 55). The controller determines whether the impedance change is higher than the impedance threshold Th Contact (decision block 56).

[0091] If so, the controller determines the impedance change rate (block 71). Specifically, the controller determines the rate Rate at which the impedance of the blade changes over a period (e.g., based on the monitored (determined) change in impedance over a period). ΔImp For example, over a period Δt, the controller may determine and store in memory one or more changes in impedance (e.g., by performing the operation of block 54 one or more times). For example, the rate may be as follows.

[0092]

Number

[0093] The controller determines whether the impedance change rate is higher than the threshold rate (decision block 72). Specifically, the control unit determines if Rate ΔImp > Th Rate where the threshold rate may be a predetermined threshold (e.g., determined in a controlled environment). If so, the controller determines that the end effector is in contact with the object (in block 69) and presents a notification indicating that the end effector is in contact with the object (in block 73). If not, Rate ΔImp < Th Rateand the controller determines that the shaft of the ultrasonic instrument is in contact with the object (block 100). In that 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). In another aspect, the controller may present a notification indicating that the shaft of the ultrasonic instrument is in contact with the object.

[0094] FIG. 8 shows some stages of a display of a surgical system that displays operations performed by an end effector of an ultrasonic instrument and displays a notification based on whether the end effector is in contact with an object. Specifically, each of the four stages 80-83 shows a display 15 that displays an endoscopic video 84 showing the end effector 23 and the shaft 22 of the instrument, and a portion of the object 85 (e.g., tissue such as a blood vessel). In one aspect, the display showing the endoscopic video may be a different display of the surgical system, such as the display 24 of the generator 25. In some aspects, the display may show other content, such as a graphical user interface (GUI) of the surgical system that displays other video content and / or one or more UI items (e.g., related to a surgical procedure being performed by the operator of the system).

[0095] The first stage 80 shows that the end effector 23 is gripping a portion of the tissue to cut the tissue. At this stage, the ultrasonic instrument may be in a heating cycle with the hinge arm 31 in the closed position, thereby compressing the tissue between the arm 31 and the blade 30. As described herein, while in the closed position and in the heating cycle, the blade may cut the tissue using frictional heat due to the vibration of the blade.

[0096] The second stage 81 shows the result of the end effector 23 cutting the tissue. In particular, this stage shows that the tissue has been cut into two pieces. Note that the ultrasonic instrument is in a cooling cycle and the hinge arm is in the open position. Thus, at this stage, the surgical system 1 (e.g., its controller 40) may perform one or more of the operations described herein to detect whether the instrument is in contact with the object. For example, the controller may be configured to start monitoring the impedance and / or resonant frequency of the end effector as described herein (e.g., when the instrument enters the cooling cycle).

[0097] The third stage 82 shows that the shaft 22 of the ultrasonic instrument is in contact with (touching) a portion of the tissue 85. As described herein, the controller may detect that the shaft is in contact with the object based on the determined impedance of the end effector not exceeding a threshold. In particular, the controller may determine that there is a change in impedance (e.g., based on the detected impedance being higher than the baseline impedance), but this change is not greater than the threshold (e.g., ΔImp < ΔI Shaft ).

[0098] The fourth stage 83 indicates that the blade 30 of the end effector 23 has moved and is now in contact with 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 the endoscopic video 84) to notify the operator that the blade of the end effector is touching the object. As described herein, the controller may present this notification in response to a change in impedance being higher than an impedance threshold. In another aspect, this notification may also be displayed in response to the blade of the end effector having a temperature higher than a temperature threshold, thereby warning the operator that the blade is in contact with the tissue in case the blade gets too hot to touch an object such as sensitive tissue.

[0099] Accordingly, this figure shows how the controller continuously monitors the state of the instrument (e.g., whether the end effector is in contact with an object) and performs at least a portion of the operations of the process described herein (e.g., continuously) to update the operator. Specifically, the controller may continuously monitor the characteristics of the ultrasonic instrument such as impedance and use the impedance to determine whether the end effector is in contact with an object. If so, the operator may be notified, for example, via a pop-up notification (which may also display the temperature of the end effector).

[0100] FIG. 9 is a flowchart of process 90 for detecting that an end effector of an ultrasonic instrument is in contact with an object. The process starts when the controller determines the temperature of the end effector of the ultrasonic instrument based on one or more characteristics of the end effector (e.g., resonance frequency and / or impedance) (block 91). The controller determines that the end effector is in contact with the object (block 92). In particular, the controller may determine whether the end effector and / or another part of the instrument, such as the 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 the impedance being higher than an impedance threshold) and that the temperature (indicating that it is too hot for the end effector to contact the object 0) is higher than a temperature threshold, a notification indicating that it is too hot for the end effector to contact the object is presented (displayed) (block 93). As described herein, the notification may also display the temperature of the end effector (e.g., the blade of the end effector).

[0101] Some aspects may implement one or more variations to one or more of the processes described herein. For example, the particular operations of one or more processes may not be performed in the exact order illustrated and described. The particular operations may not be performed in one continuous series of operations, and different particular operations may be performed in different manners.

[0102] As described above, one aspect of the present disclosure may be a non-transitory machine-readable medium (such as a microelectronic memory) having stored thereon instructions for programming one or more data processing components (herein generally referred to as "processors") to perform (automatically) 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 including hardwired logic. These operations may alternatively be performed by any combination of programmed data processing components and fixed hardwired circuit components.

[0103] Although specific aspects have been described and illustrated in the accompanying drawings, such aspects are merely illustrative of the broader disclosure and do not limit the broader disclosure, and various other modifications may be contemplated by those skilled in the art, it should be understood that the present disclosure is not limited to the specific structures and arrangements shown and described. Accordingly, this description should be regarded as illustrative rather than limiting.

[0104] In some aspects, the present disclosure may include, for example, language such as "at least one of [element A] and [element B]". This 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 either A or B". In some aspects, the present disclosure may include, for example, language such as "[element A], [element B], and / or [element C]". This language may refer to any one of the elements or any combination thereof. For example, "A, B, and / or C" may refer to "A", "B", "C", "A and B", "A and C", "B and C", or "A, B, and C".

[0105] [Embodiment] (1) A method implemented by a surgical system including 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 an object; presenting a notification indicating that the end effector is too hot to be in contact with the object in response to determining that the end effector is in contact with the object and that the temperature is higher than a threshold temperature. (2) 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 the baseline impedance of the end effector, according to the method of Embodiment 1. (3) Determining a plurality of impedances of the end effector over a period of time, determining that a change in impedance over the plurality of impedances throughout the period is less than a threshold, and further including determining the baseline impedance using the plurality of impedances in response to determining that the change is less than the threshold, according to the method of Embodiment 2. (4) The baseline impedance is the average impedance over the plurality of impedances, according to the method of Embodiment 3. (5) The determining the temperature, the determining that the end effector is in contact with the object, and the presenting the notification are performed while the ultrasonic instrument is in a cooling cycle, according to the method of Embodiment 1.

[0106] (6) The end effector is coupled to the handle of the ultrasonic instrument via a shaft, and the method further includes determining whether the shaft or the end effector is in contact with an object based on the impedance of the end effector, and determining that the end effector is in contact with the object when the impedance is higher than an impedance threshold, according to the method of Embodiment 1. (7) The impedance threshold is a first impedance threshold, and the method includes determining that the shaft and the end effector of the ultrasonic instrument are in contact with the object when the impedance is higher than a second impedance threshold that is higher than the first impedance threshold, 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, further comprising the method according to Embodiment 6. (8) A surgical system, an ultrasonic instrument having an end effector, a display, a processor, a memory having instructions that, when executed by the processor, cause the instructions to cause the surgical system to determine the temperature of the end effector based on one or more characteristics of the end effector, determine that the end effector is in contact with an object, a memory that, in response to determining that the end effector is in contact with the object and that the temperature is higher than a threshold temperature, causes a notification to be presented that the end effector is too hot to be in contact with the object, comprising a surgical system. (9) The surgical system according to Embodiment 8, wherein the instructions for determining that the end effector is in contact with the object include instructions for determining that the impedance of the end effector exceeds an impedance threshold relative to the baseline impedance of the end effector. (10) The memory determines a plurality of impedances of the end effector over a period of time, determines that a change in impedance over the plurality of impedances throughout the period is less than a threshold, The surgical system according to Embodiment 9, further having instructions for determining the baseline impedance using the plurality of impedances in response to determining that the change is less than the threshold.

[0107] (11) The surgical system according to Embodiment 10, wherein the baseline impedance is an average impedance over the plurality of impedances. (12) The command for determining the temperature, determining that the end effector is in contact with the object, and presenting the notification is implemented while the ultrasonic instrument is in a cooling cycle, according to the surgical system of embodiment 8. (13) The end effector is coupled to the handle of the ultrasonic instrument via a shaft, and the memory has further instructions for determining whether the shaft or the end effector is in contact with an object based on the impedance of the end effector. When the impedance is higher than an impedance threshold, it is determined that the end effector is in contact with the object, according to the surgical system of embodiment 8. (14) The impedance threshold is a first impedance threshold, and the memory when the impedance is higher than a second impedance threshold that is higher than the first impedance threshold, determines that the shaft and the end effector of the ultrasonic instrument are in contact with the object, and in response to determining that the shaft and the end effector are in contact with the object, has further instructions for presenting a notification indicating that the end effector and the shaft are in contact with the object, according to the surgical system of embodiment 13. (15) A method implemented by a surgical system including an ultrasonic instrument, the method comprising: determining a temperature of a blade of the ultrasonic instrument, the blade having a handle coupled to the blade via a shaft, determining 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 higher than a threshold temperature, displaying a notification on a display of the surgical system.

[0108] (16) Further including determining a rate at which the impedance of the blade changes over a period of time, determining whether the blade or the 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 of the impedance of the blade is higher than a threshold rate, the method according to embodiment 15. (17) Further including determining the impedance of the blade, and determining that the blade is in contact with the object in response to the rate of change of the impedance of the blade being higher than the threshold rate and the impedance of the blade being higher than a threshold, the method according to embodiment 16. (18) Determining whether the blade or the 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 with respect to the baseline impedance of the blade, the method according to embodiment 15. (19) 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 device is in a cooling cycle, the method according to embodiment 15. (20) The notification includes a display that the blade is in contact with the object and includes the temperature of the blade, the method according to embodiment 15.

Claims

1. A method carried out by a surgical system including an ultrasonic instrument, wherein the method is: Using a generator configured to supply power to the ultrasonic device, the resonant frequency and impedance of the ultrasonic device, including the end effector loaded into the cannula, are determined while the generator supplies power to the ultrasonic device. Using the aforementioned resonant frequency, The temperature of the end effector of the ultrasonic device, The first impedance threshold associated with the cannula, and A second impedance threshold associated with the end effector, To decide, 1) whether the end effector is in contact with the object, and 2) whether the cannula is in contact with the object, are determined based on a first comparison between the impedance and the first impedance threshold, and a second comparison between the impedance and the second impedance threshold. A method comprising: in response to the determination that the end effector is in contact with the object and that the temperature is above a threshold temperature, the end effector presents a notification indicating that it is too hot to be in contact with the object.

2. Determining the baseline impedance of the ultrasonic device, The method further includes determining the impedance change based on the baseline impedance and the impedance, The first comparison is performed between the impedance change and the first impedance threshold. The method according to claim 1, wherein the second comparison is performed between the impedance change and the second impedance threshold.

3. Determining multiple impedances of the end effector over a certain period of time, Determining that the change in impedance across the multiple impedances over the entire aforementioned period is less than a threshold, The method of claim 2, further comprising determining the baseline impedance using the plurality of impedances in response to determining that the change is less than the threshold.

4. The method according to claim 3, wherein the baseline impedance is the average impedance over the plurality of impedances.

5. The method according to claim 1, wherein each operation of the method is performed by the surgical system while the ultrasonic instrument is in a cooling cycle.

6. The end effector is connected to the handle of the ultrasonic instrument via the cannula. Determining whether the end effector is in contact with the object includes determining whether the impedance is higher than the first impedance threshold, The method according to claim 1, wherein determining whether the cannula is in contact with the object includes determining whether the impedance is lower than the first impedance threshold.

7. Determining whether the end effector is in contact with the object includes determining whether the impedance is higher than the first impedance threshold and less than or equal to the second impedance threshold, The method according to claim 6, wherein determining whether the end effector and the cannula are in contact with the object includes determining whether the impedance is higher than both the first impedance threshold and the second impedance threshold.

8. A surgical system, An ultrasonic instrument having a shaft and an end effector received through the shaft, A generator configured to supply power to the ultrasonic device, The display and Processor and A memory having instructions, wherein when executed by the processor, the instructions are transmitted to the surgical system. From the generator, while the generator is supplying power to the ultrasonic device, the resonant frequency and impedance of the end effector are received. Using the aforementioned resonant frequency, the following are determined: 1) the temperature of the end effector, 2) a first impedance threshold associated with the shaft, and 3) a second impedance threshold associated with the end effector. 1) whether the end effector is in contact with the object, and 2) whether the shaft is in contact with the object, are determined based on a first comparison between the impedance and the first impedance threshold, and a second comparison between the impedance and the second impedance threshold. A surgical system comprising: a memory that, in response to the determination that the end effector is in contact with the object and that the temperature is higher than a threshold temperature, prompts the system to display a notification that the end effector is too hot to contact the object.

9. The memory is Determine the baseline impedance of the end effector, Includes further instructions for determining impedance changes based on the baseline impedance and the impedance, The first comparison is performed between the impedance change and the first impedance threshold. The surgical system according to claim 8, wherein the second comparison is performed between the impedance change and the second impedance threshold.

10. The aforementioned memory is Determine the multiple impedances of the end effector over a certain period of time, It is determined that the change in impedance across the multiple impedances over the entire aforementioned period is less than a threshold. The surgical system according to claim 9, further comprising instructions for determining the baseline impedance using the plurality of impedances in response to determining that the change is below the threshold.

11. The surgical system according to claim 10, wherein the baseline impedance is the average impedance over the plurality of impedances.

12. The surgical system according to claim 8, wherein the instruction is performed while the ultrasonic instrument is in a cooling cycle.

13. The end effector is coupled to the handle of the ultrasonic instrument via the shaft, and the memory is If the impedance is higher than the first impedance threshold, it is determined that at least the end effector is in contact with the object. The surgical system according to claim 8, further comprising instructions for determining that only the shaft is in contact with the object when the impedance is lower than the first impedance threshold.

14. The command for determining whether the end effector is in contact with the object includes a command for determining whether the impedance is higher than the first impedance threshold and less than or equal to the second impedance threshold, The surgical system according to claim 13, wherein the command for determining whether the end effector and the shaft are in contact with the object includes determining whether the impedance is higher than both the first impedance threshold and the second impedance threshold.

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