Technology for controlling therapeutic and subtherapeutic activation of energy-based surgical instruments

Abstract

A method for controlling an energy-based surgical instrument includes: activating an energy control signal at a subtherapeutic level; measuring a system response at the subtherapeutic level; adjusting one or more parameters based on the system response; and then activating the energy control signal at a therapeutic level according to the determined parameters. The subtherapeutic signal and the therapeutic signal may be ultrasonic energy or radio frequency (RF) energy and / or a combination of ultrasonic energy and RF energy. Controlled parameters may include mode, cycle time, power (e.g., ultrasound end-effector displacement), or crest factor. Other embodiments are described and claimed in this invention.

Description

Cross-references to related applications

[0001] This application claims the benefit and priority of U.S. Patent Application No. 63 / 740,944, filed on December 31, 2024, entitled “TECHNOLOGIES FOR THERAPEUTICAND SUBTHERAPEUTIC CONTROL OF ENERGY-BASED SURGICAL INSTRUMENTS”, the entire contents of which are incorporated herein by reference. Technical Field

[0002] This disclosure relates generally to energy-based surgical instruments, and more specifically to harmonic and / or electrosurgical instruments. Background Technology

[0003] Energy-based surgical instruments are increasingly used in surgical procedures due to their unique performance characteristics. Depending on the specific device configuration and operating parameters, energy-based surgical instruments can provide both transverse incisions of tissue and tissue hemostasis through coagulation, which can reduce or otherwise minimize patient trauma. Depending on the specific application, energy-based surgical instruments can utilize various surgical techniques, including, for example, ultrasound and / or electrosurgery (e.g., radiofrequency (RF)).

[0004] Typical ultrasonic surgical instruments may include a handheld component comprising an ultrasonic transducer and a slender shaft assembly with a distally mounted end effector for cutting and sealing tissue. For example, the end effector may include a jaw assembly with an ultrasonic scalpel and a gripping arm, the gripping arm including a non-adhesive tissue pad or similar base to receive the ultrasonic scalpel. In some cases, the slender shaft assembly may be permanently attached to the handheld component. In other cases, such as in the presence of disposable shaft assemblies or shaft assemblies interchangeable between different handheld components, the slender shaft assembly may be detached from the handheld component. In use, the end effector transmits ultrasonic energy to the tissue in contact with the ultrasonic scalpel of the end effector to achieve cutting and sealing actions. Such ultrasonic surgical devices can be configured for open surgical purposes, laparoscopic and / or endoscopic surgical procedures, including robot-assisted procedures.

[0005] Ultrasonic energy uses temperatures lower than those used in electrosurgical procedures to cut and coagulate tissue. Through high-frequency vibrations (e.g., 55,500 times per second), the ultrasonic scalpel denatures proteins in the tissue to form a viscous coagulate. The pressure applied to the tissue by the surface of the ultrasonic scalpel causes blood vessels to collapse and the coagulate to form a hemostatic seal. The surgeon can control the cutting speed and coagulation by the force applied to the tissue by the end effector, the duration of that force application, and the selected offset level of the end effector.

[0006] In electrosurgical instruments, one or more electrodes are incorporated into an end effector and configured to apply a therapeutic current to the patient's tissue to form a hemostatic seal. In electrosurgical instruments that do not include harmonic modes (i.e., do not include a harmonic scalpel), the end effector may be embodied as two gripping arms or jaws. In such embodiments, the electrosurgical instrument may include a separate mechanical blade or scalpel for cutting tissue after the hemostatic seal has been formed, which may be incorporated into an elongated shaft attached to the end effector. In bipolar embodiments, an active electrode may be attached to one of the gripping arms of the end effector and configured to introduce current into the tissue, which is received by a return electrode attached to the other gripping arm of the end effector (or, in embodiments including harmonic modes, as the scalpel itself). Conversely, in unipolar embodiments, the return electrode (e.g., a "grounding pad") may be separate from the electrosurgical instrument and located on a different part of the patient's body. In some embodiments, the electrosurgical instrument may also be configured to apply a subtherapeutic current to the patient's tissue, which may be used for sensing purposes (e.g., measuring tissue impedance).

[0007] Electrosurgery creates a hemostatic seal by generating heat in the tissue via introduced electrical energy, which is embodied in radio frequency (“RF”) energy. The specific frequency used can vary from about 100 kHz to 1 MHz depending on the intended use of the electrosurgical instrument, but higher frequencies may be used in some implementations. Additionally, in some cases, sub-therapeutic frequencies may be used for purposes other than hemostatic sealing, such as performing various electrical measurements on the tissue.

[0008] It should be understood that some energy-based surgical instruments can employ dual-mode or multi-mode techniques to perform transverse incisions and / or hemostasis of patient tissue. For example, in some cases, energy-based surgical instruments may include both ultrasound and electrosurgical functions (e.g., by utilizing an ultrasonic scalpel as an electrode for the electrosurgical mode), which increases the surgical options offered to the surgeon by the surgical instrument. Summary of the Invention

[0009] According to one aspect of this disclosure, a method for controlling a surgical instrument includes: activating a first energy signal at a subtherapeutic level by a control element, wherein the first energy signal is output by a surgical generator coupled to the surgical instrument, and wherein the surgical instrument includes an end effector configured to deliver energy to a patient's tissue; measuring a system response in response to activation of the first energy signal by the control element; determining activation parameters by the control element based on the system response; and activating a second energy signal at a therapeutic level by the control element according to the activation parameters, wherein the second energy signal is output by the surgical generator.

[0010] In some embodiments, the first energy signal includes an ultrasonic signal or a radio frequency (RF) signal; and the second energy signal includes an ultrasonic signal or a radio frequency (RF) signal. In some embodiments, the system response includes impedance, the rate of change of impedance, or acoustic impedance. In some embodiments, the activation parameters include power, current, or duration.

[0011] According to another aspect, a method for controlling a surgical instrument includes: determining an activation mode of the surgical instrument by a control element of the surgical instrument, wherein the surgical instrument includes an end effector having a first electrode configured to deliver radio frequency (RF) energy to a patient's tissue; determining a waveform of an energy signal by the control element based on the activation mode; programming an electrosurgical generator coupled to the surgical instrument by the control element using the waveform in response to determining the waveform; and delivering an energy signal to the electrode of the end effector by the electrosurgical generator in response to programming the electrosurgical generator.

[0012] In some implementations, the activation mode includes a cutting mode, a solidification mode, or a mixing mode. In some implementations, determining the waveform includes determining the waveform crest factor based on the activation mode.

[0013] In some embodiments, determining the waveform includes, when the activation mode is a cut mode, determining a first waveform having a first crest factor corresponding to a sine waveform. In some embodiments, determining the waveform includes, when the activation mode is a solidification mode, determining a second waveform having a second crest factor greater than the first crest factor. In some embodiments, the second waveform includes a pulse train of a damped sine wave.

[0014] In some embodiments, determining the waveform includes, when the activation mode is a mixed mode, determining a third waveform with a third crest factor, the third crest factor being between the first crest factor and the second crest factor. In some embodiments, the third waveform includes a pulse train of a damped sine wave mixed with an undamped sine wave. In some embodiments, the third waveform includes a sine wave modulated with a second, lower frequency sine wave.

[0015] In some embodiments, delivering the energy signal includes generating an analog output signal of the energy signal using direct digital synthesis. In some embodiments, programming includes storing digital values ​​indicating the waveform in the memory of the electrosurgical generator.

[0016] In some embodiments, the method further includes having a control element determine an updated waveform of the energy signal based on the electrical characteristics of the tissue sensed by the end effector; and having the control element update the programming of the electrosurgical generator using the updated waveform. In some embodiments, determining the updated waveform includes adding a crest factor to the waveform from a predetermined crest factor associated with a sine waveform.

[0017] According to another aspect, a method for controlling a surgical instrument includes: when pressure is applied in the jaws of the surgical instrument, performing a radio frequency (RF) energy cycle by the surgical instrument using a first electrode of an end effector of the surgical instrument; after performing the RF energy cycle, releasing the pressure in the jaws of the surgical instrument; after releasing the pressure in the jaws of the surgical instrument, measuring a first acoustic impedance of the surgical instrument using a subtherapeutic ultrasound signal by a control element using an ultrasonic scalpel of the end effector; determining, based on the first acoustic impedance, whether tissue is adhered to the jaws of the surgical instrument by the control element; and in response to determining that tissue is adhered to the jaws of the surgical instrument, activating an automatic ultrasonic energy release cycle by the control element using the ultrasonic scalpel of the surgical instrument.

[0018] In some embodiments, the method further includes measuring the baseline acoustic impedance of the surgical instrument using subtherapeutic ultrasound signals by a control element; wherein determining whether tissue is stuck includes comparing the first acoustic impedance with the baseline acoustic impedance. In some embodiments, determining whether tissue is stuck also includes determining whether the closing switch of the surgical instrument has moved to the open position.

[0019] In some embodiments, determining whether tissue is stuck includes determining whether tissue is stuck based on the absolute value of a first acoustic impedance. In some embodiments, the method further includes measuring the acoustic impedance of the surgical instrument using subtherapeutic ultrasound signals by a control element during RF energy cycling or during device idle time.

[0020] According to another aspect, a system for controlling a surgical instrument includes a surgical instrument, a surgical generator coupled to the surgical instrument, and a control element. The surgical instrument includes an end effector configured to deliver energy to a patient's tissue. The control element is configured to activate a first energy signal at a subtherapeutic level, wherein the first energy signal is output by the surgical generator; measure a system response in response to the activation of the first energy signal; determine activation parameters based on the system response; and activate a second energy signal at a therapeutic level according to the activation parameters, wherein the second energy signal is output by the surgical generator.

[0021] In some embodiments, the first energy signal includes an ultrasonic signal or a radio frequency (RF) signal; and the second energy signal includes an ultrasonic signal or a radio frequency (RF) signal. In some embodiments, the system response includes impedance, the rate of change of impedance, or acoustic impedance. In some embodiments, the activation parameters include power, current, or duration.

[0022] According to another aspect, a system for controlling a surgical instrument includes a surgical instrument, an electrosurgical generator coupled to the surgical instrument, and a control element. The surgical instrument includes an end effector having a first electrode configured to deliver radio frequency (RF) energy to a patient's tissue. The control element is configured to determine an activation mode of the surgical instrument, determine a waveform of an energy signal based on the activation mode, and program the electrosurgical generator using the waveform in response to the determination of the waveform. The electrosurgical generator is configured to deliver an energy signal to the electrode of the end effector in response to the programming of the electrosurgical generator.

[0023] In some implementations, the activation mode includes a cutting mode, a solidification mode, or a mixing mode. In some implementations, determining the waveform includes determining the waveform crest factor based on the activation mode.

[0024] In some embodiments, determining the waveform includes determining a first waveform having a first crest factor corresponding to a sine waveform when the activation mode is a cut mode. In some embodiments, determining the waveform includes determining a second waveform having a second crest factor greater than the first crest factor when the activation mode is a solidification mode. In some embodiments, the second waveform includes a pulse train of a damped sine wave.

[0025] In some embodiments, determining the waveform includes, when the activation mode is a mixed mode, determining a third waveform with a third crest factor, the third crest factor being between the first crest factor and the second crest factor. In some embodiments, the third waveform includes a pulse train of a damped sine wave mixed with an undamped sine wave. In some embodiments, the third waveform includes a sine wave modulated with a second, lower frequency sine wave.

[0026] In some embodiments, delivering the energy signal includes generating an analog output signal of the energy signal using direct digital synthesis. In some embodiments, programming the electrosurgical generator includes storing digital values ​​indicating the waveform in the memory of the electrosurgical generator.

[0027] In some embodiments, the control element is also configured to determine an updated waveform of the energy signal based on the electrical characteristics of the tissue sensed by the end effector; and to update the programming of the electrosurgical generator using the updated waveform. In some embodiments, determining the updated waveform includes adding a crest factor to the waveform from a predetermined crest factor associated with a sine waveform.

[0028] According to another aspect, a system for controlling a surgical instrument includes a surgical instrument and a control element. The surgical instrument includes an end effector comprising jaws having a first electrode configured to deliver radio frequency (RF) energy to a patient's tissue and an ultrasonic scalpel configured to deliver ultrasonic energy to the patient's tissue. The control element is configured to perform an RF energy cycle using the first electrode when pressure is applied in the jaws of the surgical instrument; after performing the RF energy cycle, release the pressure in the jaws of the surgical instrument; after releasing the pressure in the jaws of the surgical instrument, measure a first acoustic impedance of the surgical instrument using a subtherapeutic ultrasound signal with the ultrasonic scalpel; determine, based on the first acoustic impedance, whether tissue is adhered to the jaws of the surgical instrument; and, in response to determining that tissue is adhered to the jaws of the surgical instrument, activate an automatic ultrasonic energy release cycle using the ultrasonic scalpel of the surgical instrument.

[0029] In some embodiments, the control element is also configured to measure the baseline acoustic impedance of the surgical instrument using subtherapeutic ultrasound signals. Determining whether tissue is stuck includes comparing the first acoustic impedance to the baseline acoustic impedance. In some embodiments, determining whether tissue is stuck also includes determining whether the closing switch of the surgical instrument has moved to the open position.

[0030] In some embodiments, determining whether tissue is stuck includes determining whether tissue is stuck based on the absolute value of a first acoustic impedance. In some embodiments, the control element is also configured to measure the acoustic impedance of the surgical instrument using subtherapeutic ultrasound signals during RF energy cycling or during device idle time. Attached Figure Description

[0031] The specific implementation method refers to the following figures, in which:

[0032] Figure 1 This is a simplified diagram of the implementation scheme for a system used to perform energy-based surgical procedures;

[0033] Figure 2 yes Figure 1 A perspective view of an implementation scheme for an energy-based surgical instrument system;

[0034] Figure 3 It includes an ultrasonic scalpel and is in the open position. Figure 2 A side front view of the jaw assembly of the end effector of a surgical instrument;

[0035] Figure 4 It includes an ultrasonic scalpel and is in a closed state. Figure 2 A side front view of the jaw assembly of the end effector of a surgical instrument;

[0036] Figure 5A yes Figure 2A perspective view of another embodiment of an end effector for a surgical instrument, the end effector including electrodes on the lower jaw gripper of a jaw assembly;

[0037] Figure 5B yes Figure 2 A perspective view of another embodiment of an end effector for a surgical instrument, the end effector comprising two jaw grippers, each jaw gripper having an electrode attached thereto;

[0038] Figure 6 yes Figure 2 Exploded view of surgical instruments;

[0039] Figure 7 yes Figure 2 A block diagram of the control circuit for a surgical instrument;

[0040] Figure 8 It is a simplified flowchart of at least one method for controlling energy-based surgical instruments;

[0041] Figure 9 It is a simplified flowchart of at least one method for controlling radio frequency (RF) or combined energy-based surgical instruments;

[0042] Figure 10 This is an example based on Figure 9 A schematic diagram of the output of the surgical instruments in the method;

[0043] Figure 11 It is a simplified flowchart of a method for controlling at least one combined energy-based surgical instrument with automated ultrasonic release;

[0044] Figure 12 This is an example of what can be done with Figure 11 A graph illustrating the relationship between the measured impedance and force of a surgical instrument used in an exemplary embodiment of the method; and

[0045] Figure 13 This is an example based on Figure 11 A diagram illustrating the operation of surgical instruments. Detailed Implementation

[0046] While the concepts of this disclosure are readily available in various modifications and alternatives, specific exemplary embodiments thereof have been shown by way of example in the accompanying drawings and will be described in detail herein. However, it should be understood that this disclosure is not intended to limit the concepts to the specific forms disclosed, but rather, the object of the invention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the appended claims.

[0047] Throughout this specification, when referring to the surgical instruments described herein and the natural anatomical structures of patients, terms indicating anatomical reference, such as anterior, posterior, medial, lateral, superior, inferior, distal, proximal, etc., may be used. These terms have well-known meanings in anatomical studies and surgery. Unless otherwise stated, these anatomical reference terms used in the written details and claims are intended to be consistent with their well-known meanings.

[0048] References to "an embodiment," "an embodiment," "an exemplary embodiment," etc., in this specification mean that the embodiment may include a particular feature, structure, or characteristic, but each embodiment may or may not include that particular feature, structure, or characteristic. Furthermore, these phrases do not necessarily refer to the same embodiment. Additionally, when a particular feature, structure, or characteristic is described in connection with an embodiment, whether or not it is explicitly described, it should be assumed that implementing such a particular feature, structure, or characteristic in combination with other embodiments is within the knowledge of a person skilled in the art. Furthermore, it should be understood that items included in a list in the form of "at least one of A, B, and C" may mean (A); (B); (C); (A and B); (A and C); (B and C); or (A, B, and C). Similarly, items listed in the form of "at least one of A, B, or C" may mean (A); (B); (C); (A and B); (A and C); (B and C); or (A, B, and C).

[0049] In some cases, the disclosed embodiments may be implemented in hardware, firmware, software, or any combination thereof. The disclosed embodiments may also be implemented as instructions carried or stored on a transient or non-transitory machine-readable (e.g., computer-readable) storage medium, which may be read and executed by one or more processors. The machine-readable storage medium may be embodied in any storage device, mechanism, or other physical structure (e.g., volatile or non-volatile memory, media disk, or other media device) for storing or transmitting information in a machine-readable form.

[0050] In the accompanying drawings, some structural or methodological features may be shown in a specific arrangement and / or order. However, it should be understood that such a specific arrangement and / or order may not be necessary. Instead, in some embodiments, such features may be arranged in a different manner and / or order than those shown in the illustrative drawings. Furthermore, the inclusion of structural or methodological features in a particular drawing does not imply that such features are necessary in all embodiments, and in some embodiments, these features may be omitted or may be combined with other features.

[0051] See now Figure 1 and Figure 2In an exemplary embodiment, system 100 for performing energy-based surgical procedures includes a surgical instrument 102, a transducer 104, and a generator 106. The surgical instrument 102 is exemplarily embodied as an ultrasound surgical instrument, but in other embodiments may be embodied as an electrosurgical surgical instrument or a multimodal ultrasound / electrosurgical surgical instrument. In use, the surgical instrument 102 can be used to perform various surgical procedures, including laparoscopic, endoscopic, or conventional open surgical procedures. In doing so, the surgeon may selectively activate an ultrasound mode (and / or an electrosurgical / RF mode) of the surgical instrument 102. In ultrasound mode, the generator 106 drives the transducer 104 to cause the ultrasonic scalpel 130 of the jaw assembly 122 of the end effector 120 of the surgical instrument 102 to vibrate at a reference frequency, which facilitates simultaneous cutting of patient tissue and hemostatic sealing. Additionally or alternatively, in some embodiments, the surgeon may selectively activate an electrosurgical mode of the surgical instrument 102 to deliver a therapeutic RF energy to the patient tissue to achieve hemostatic sealing. In such embodiments, the blade 130 may be embodied as an ultrasonic blade 130 or a mechanical blade designed to use mechanical force to cut tissue (e.g., in those embodiments that do not employ ultrasonic technology). Furthermore, in some embodiments, the surgical instrument 102 may be configured to have only an electrosurgical / RF mode, and in such embodiments, the jaw assembly 122 of the end effector 120 may not include the ultrasonic blade 130, as described below. Figure 5B To be discussed in more detail.

[0052] Surgical instrument 102 is illustratively embodied as ultrasonic surgical scissors, but in other embodiments may be embodied as other types of surgical instruments having an ultrasonic mode and / or an electrosurgical mode. In an illustrative embodiment, surgical instrument 102 includes a handle assembly 110 and an elongated shaft assembly 112 extending distally away from the handle assembly 110 and, in some embodiments, removably attached to the handle assembly 110. The elongated shaft assembly 112 includes an end effector 120 located at a distal end remote from the handle assembly 110. The end effector 120 includes a jaw assembly 122, which illustratively includes an ultrasonic scalpel 130 and a corresponding jaw clamp 132 (but in those embodiments having only an electrosurgical / RF mode, two jaw clamps may be included). Figure 3 and Figure 4 As shown, the jaw assembly 122 can be in the open state ( Figure 3 ) and closed state ( Figure 4The jaw assembly 122 moves between the open and closed states. In the open state, the jaw clamp 132 is positioned away from the ultrasonic scalpel 130, and in the closed state, the jaw clamp 132 is positioned near or otherwise in contact with the ultrasonic scalpel 130. Actuation of the jaw assembly 122 from the open to the closed state allows for grasping, cutting, and coagulating blood vessels and / or tissues. It should be understood that the open state may correspond to a degree of opening less than the fully open position of the jaw assembly 122, and the closed state may correspond to a degree of closure less than the fully closed position. That is, the closed state may, for example, correspond to the minimum distance between the distal end of the jaw clamp 132 and the ultrasonic scalpel 130, and the open state may correspond to the maximum distance between the distal end of the jaw clamp 132 and the ultrasonic scalpel 130. However, in other embodiments, the open state may correspond to the fully open position of the jaw assembly 122, and the closed state may correspond to the fully closed position of the jaw assembly 122.

[0053] In those embodiments where the surgical instrument 102 includes both ultrasound mode and electrosurgical / RF mode, the end effector 120 may include one or more RF electrodes 500 coupled to the jaw clamp 132, such as Figure 5A As shown. Although in Figure 5A In some embodiments, the exemplary end effector 120 includes only a single electrode 500, but it should be understood that in other embodiments, the end effector 120 may include additional electrodes 500 (e.g., multiple electrode pads 500). Electrode 500 may be embodied as an active electrode configured to deliver RF energy or a return electrode configured to “absorb” the applied RF energy. In those embodiments utilizing bipolar RF, the ultrasonic scalpel 130 may embody an active electrode or a return electrode, wherein electrode 500 embodies another active electrode or return electrode. Alternatively, other active electrodes or return electrodes may be incorporated into the ultrasonic scalpel 130 or into another portion of the jaw assembly 122 of the end effector 120. In monopolar embodiments, the RF electrode 500 may be embodied as an active electrode, and the return electrode may be attached to a portion of the patient's body.

[0054] In those embodiments where the surgical instrument 102 includes only the electrosurgical / RF mode, the jaw assembly 122 of the end effector 120 includes a jaw clamping member 532, which replaces the ultrasonic scalpel 130, such as Figure 5B As shown. In such embodiments, electrode 500 may be attached to or otherwise incorporated into each jaw clamp 132, 532 and embodied as an active electrode or a return electrode to facilitate the application of RF energy to tissue captured between jaw clamps 132, 532. In such embodiments, surgical instrument 102 may include a blade incorporated into an elongated shaft assembly 112, the blade being configured to eject outward after the tissue has been sealed with RF energy to cut the patient's tissue.

[0055] See again Figure 1 and Figure 2 In embodiments that include ultrasound capability, the handle assembly 110 includes a receiver 140 configured to receive a transducer 104 to facilitate connection of the transducer 104 to the handle assembly 110 and the elongated shaft assembly 112. The handle assembly 110 also includes a trigger assembly 150 comprising a master trigger 152 and a switch assembly 154. The master trigger 152 is operable by a surgeon to move the jaw assembly 122 of the end effector 120 between an open and closed state. The switch assembly 154 includes one or more buttons operable by a surgeon to activate (and in some embodiments, configure) an ultrasound mode and / or an electrosurgical mode of the surgical instrument 102.

[0056] Transducer 104 is illustratively connected to generator 106 via cable assembly 108. As described above, generator 106 is configured to drive transducer 104 at a reference frequency or resonant frequency, thereby causing ultrasonic scalpel 130 to vibrate. For example, in one exemplary embodiment, generator 106 may supply an electrical signal to transducer 104 to cause ultrasonic scalpel 130 of jaw assembly 122 to vibrate longitudinally in, for example, a range of approximately 20 kHz to 250 kHz. In a specific embodiment, for example, ultrasonic scalpel 130 may vibrate in a range of approximately 54 kHz to 56 kHz (e.g., at approximately 55.5 kHz). In other embodiments, ultrasonic scalpel 130 may vibrate at other frequencies, including, for example, approximately 31 kHz or approximately 80 kHz. The vibration offset of ultrasonic scalpel 130 can be controlled, for example, by controlling the amplitude of the electrical signal applied to transducer 104 by generator 106. Generator 106 may be activated such that electrical energy can be supplied to transducer 104 continuously or intermittently. The generator 106 also has a power cord (not shown) for plugging into an electrosurgical unit or a conventional power outlet. Alternatively, the generator 106 can be powered by a direct current (DC) source such as a battery.

[0057] In some embodiments, generator 106 may be configured to operate in different modes. In such embodiments, generator 106 may include an ultrasound generator module 162 for controlling an ultrasound mode, an electrosurgical / radiofrequency (RF) generator module 164 for controlling an electrosurgical mode, and / or other generator modules (e.g., a thermal generator module) for controlling other operating modes. In some embodiments, the various modes of generator 106 may operate independently of each other. For example, generator 106 may activate the ultrasound mode of ultrasound generator module 162 to apply ultrasound energy to jaw assembly 122, and subsequently, therapeutic or subtherapeutic RF energy may be applied to jaw assembly 122 via electrosurgical generator module 164. Alternatively, the activation modes of generator 106 may operate simultaneously or concurrently with each other.

[0058] In electrosurgical mode, the electrosurgical generator module 164 is configured to generate RF energy at frequencies ranging from approximately 100 kHz (100 kHz) to approximately 1 MHz (1 MHz). The generated RF energy is supplied to the patient's tissue via electrodes 500 of the end effector 120, as described above with respect to Figure 5. In some embodiments, the electrosurgical generator module 164 may also be configured to selectively provide subtherapeutic levels of RF energy to perform various electrical measurements of the patient's tissue. For example, the electrosurgical generator module 164 may be configured to measure the impedance of the patient's tissue using electrodes 500 and an appropriate level of RF energy.

[0059] See now Figure 6 As described above, the exemplary surgical instrument 102 includes a handle assembly 110 and an elongated shaft assembly 112 extending distally away from the handle assembly 110. The handle assembly 110 includes a housing 600, which includes a right half-housing 602 and a left half-housing 604. The half-housings 602 and 604 are configured to mate with each other to form the housing 600. To facilitate such mating, each of the half-housings 602 and 604 may include various interfaces sized to be mechanically aligned and engaged with each other to form the housing 600 and enclose the internal working parts of the surgical instrument 102.

[0060] The main trigger 152 of the trigger assembly 150 is coupled to a linkage mechanism to convert the rotational motion of the main trigger 152 into axial motion of the bracket 610, which is then configured to move the jaw assembly 122 of the end effector 120 between an open and closed state via the elongated shaft assembly 112. The main trigger 152 includes a first set of flanges 620 having openings formed therein to receive a first bracket pin 630 extending through the bracket 610. The main trigger 152 also includes a second set of flanges 622 configured to receive a first end portion of the connector 624. A trigger pin 626 is received within the openings formed in the first end portion and the second set of flanges 622 of the connector 624. The trigger pin 626 forms a trigger pivot point for the main trigger 152. The second end portion of the connector 624, opposite the first end portion, is received within a slot formed in the proximal end portion of the bracket 610 and retained therein by the second bracket pin 632. As the master trigger 152 rotates about the pivot point formed by the trigger pin 626, the carriage 610 translates horizontally. The spring 634 is used to bias the carriage forward, such that the jaw assembly 122 of the end effector 120 is biased to the open (or fully open) state.

[0061] As described above, the trigger assembly 150 also includes a switch assembly 154. The switch assembly 154 illustratively includes a toggle switch 640 selectable to activate one or more switches 642. Activation of switch 642 energizes an electrical element 644, which energizes the ultrasonic transducer 104 to induce an ultrasonic mode of the surgical instrument 102.

[0062] The elongated shaft assembly 112 includes an outer tubular sheath 650 and a knob 652 coupled to the outer tubular sheath 650. The knob 652 is operable to rotate the outer tubular sheath 650 about an axis defined by the outer tubular sheath 650. A reciprocating tubular actuator 654 is located within the outer tubular sheath 650 and is mechanically engaged at its distal end with an end effector 120. The reciprocating tubular actuator 654 is also mechanically engaged at its proximal end with a bracket 610 within the shank assembly 110 via a coupling element 656. In an embodiment including an ultrasonic mode, an ultrasonic waveguide 670 is located within the reciprocating tubular actuator 654. The distal end of the ultrasonic waveguide 670 is acoustically coupled (e.g., directly or indirectly mechanically coupled) to an ultrasonic scalpel 130, and the proximal end is acoustically coupled to a transducer 104. The ultrasonic waveguide 670 is isolated from the other components of the elongated shaft assembly 112 by a protective sheath 672 and multiple isolation elements 674. The outer tubular sheath 650, the reciprocating tubular actuator 654, and the ultrasonic waveguide 670 are mechanically engaged together via pins 658.

[0063] See now Figure 7In an exemplary embodiment, the surgical instrument 102 includes control circuitry 700. Control circuitry 700 includes a controller 702 and a trigger assembly 150, which cooperate to provide ultrasonic energy to the harmonic scalpel 130 of the jaw assembly 122 of the end effector 120 and / or to the RF electrode 500 of the jaw assembly 122, according to the operating modes of the surgical instrument 102 as described above. However, in other embodiments, control circuitry 700 may include additional or other electronic devices and / or circuitry.

[0064] Controller 702 may be embodied as any type of controller, function block, digital logic or other component, device, circuit or combination thereof capable of performing the functions described herein. In an exemplary embodiment, controller 702 includes processor 704, memory 706 and input / output (I / O) subsystem 708. Processor 704 may be embodied as any type of processor capable of performing the functions described herein. For example, processor 704 may be embodied as a single-core or multi-core processor, digital signal processor, microcontroller or other processor or processing / control circuitry. Similarly, memory 706 may be embodied as any type of volatile and / or non-volatile memory or data storage device capable of performing the functions described herein. In operation, memory 706 may store various data and software used during the operation of control circuitry 700, such as executable firmware or software, programs, libraries and drivers that may be executed by processor 704 or otherwise used.

[0065] Processor 704 and memory 706 are communicatively coupled to other components of control circuitry 700 via I / O subsystem 708, which may be embodied as circuitry and / or components to facilitate input / output operations between controller 702 (e.g., processor 704 and / or memory 706) and other components of control circuitry 700. For example, I / O subsystem 708 may be embodied as or otherwise include a memory controller hub, input / output control hub, firmware devices, communication links (i.e., point-to-point links, bus links, wires, cables, optical fibers, printed circuit board traces, etc.) and / or other components and subsystems facilitating input / output operations. In some embodiments, I / O subsystem 708 may form part of a system-on-a-chip (SoC) and be integrated onto a single integrated circuit chip along with processor 704, memory 706, and other components of surgical instrument 102. Additionally, in some embodiments, memory 706 or a portion thereof may be integrated into processor 704.

[0066] During operation, as described above, the controller 702 is configured to control the activation of the ultrasound mode and / or electrosurgical / RF mode of the surgical instrument 102. For this purpose, the controller 702 can monitor the activation of the main trigger 152 and / or one or more activation switches 154 of the trigger assembly 150. In response to the activation of the appropriate trigger 152 or switch 154, the controller 702 controls the transducer 104 to generate ultrasound energy, which is propagated to the harmonic scalpel 130 via the ultrasonic waveguide 670. Additionally or alternatively, in response to the activation of the corresponding switch 154 of the trigger assembly 150, the controller 702 can be configured to supply a certain amount of RF energy to the RF electrode 500 via the interconnect 710 through the electrosurgical generator module 164. It should be understood that although the transducer 104 and generator 106 are in... Figure 1 and Figure 7 The transducer 104 is shown as a separate component from the energy-based surgical instrument 102, but in other embodiments, the transducer 104 and / or generator 106 may be incorporated into the surgical instrument 102.

[0067] See now Figure 8 A method 800 for controlling an energy-based surgical instrument 102 is illustrated. Method 800 may be performed by a controller 702, a generator 106, and / or one or more other microcontrollers or other control elements of the system 100. Method 800 begins at block 802, where the control element determines a system activation mode for the surgical instrument 102. The system activation mode may include an energy mode (e.g., RF, ultrasound, a combination of RF and ultrasound, etc.), a surgical operation or firing performed by the surgical instrument 102 (e.g., sealing, transverse incision, sealing and transverse incision, etc.), and / or sub-operations or stages (e.g., heating, sensing, sealing, cutting, etc.).

[0068] In box 804, the control element activates one or more energy control signals at a subtherapeutic level. The subtherapeutic level can be a lower power or energy level that does not cause coagulation, transection, or other therapeutic actions in the tissue. The subtherapeutic level can also cause other responses in the tissue, such as subtherapeutic heating. Subtherapeutic control can activate ultrasound energy, RF energy, or a combination of ultrasound and RF energy at the subtherapeutic level.

[0069] In block 806, the control element measures the system response at a sub-therapeutic level. For example, the control element may measure tissue impedance, acoustic impedance, frequency shift, phase shift, or other responses to an applied sub-therapeutic signal.

[0070] In box 808, the control element determines the next system activation mode and / or parameters based on the measured system response. For example, the control element may determine whether to switch energy modes (e.g., from RF to ultrasound, from ultrasound to RF, from a single mode to a combined mode, or other changes in energy modes). As another example, the control element may determine whether to change a sub-operation or stage, such as from preheating to sealing, from sealing to transecting, or other changes within a sub-operation. As yet another example, the control element may determine one or more parameters for applying the energy level of treatment, such as setpoint, amplitude, frequency, crest factor (CF), or other parameters. As yet another example, the control element may determine that a surgical procedure (e.g., sealing and / or transecting tissue) has been completed.

[0071] In box 810, the control element checks whether the current surgical operation or firing has been completed. If so, method 800 completes. Method 800 can be executed again in response to a subsequent surgical firing. If the surgical operation has not been completed, method 800 proceeds to box 812.

[0072] In block 812, the control element activates one or more energy control signals at a treatment level determined as described above for the next system activation mode. For example, the control element may activate ultrasonic energy and / or RF energy at a setpoint determined as described above, or otherwise induce activation of the surgical instrument 102. After activation, method 800 may cycle back to block 802 to continue performing sub-therapeutic measurements and control of the applied therapeutic energy.

[0073] In addition or alternatively, in some embodiments, the control element may perform the operation of method 800 in different sequences and / or in different combinations. Furthermore, in some embodiments, the control element may perform additional or different operations and / or perform additional or different measurements. The following is in conjunction with... Figures 9 to 13 An exemplary example of control operations that can be performed in conjunction with the surgical instrument 102 is further described.

[0074] See now Figure 9 A method 900 for controlling an energy-based surgical instrument 102 is illustrated. Method 900 may be performed by a controller 702, a generator 106, and / or one or more other microcontrollers or other control elements of the system 100. Method 900 may be performed, for example, in conjunction with monopolar or bipolar electrosurgery using the surgical instrument 102. Method 900 begins at block 902, where the control element determines a system activation mode for the surgical instrument 102. The system activation mode may include a surgical operation or firing (e.g., sealing, transverse incision, sealing and transverse incision, etc.) to be performed using the surgical instrument 102 in a radio frequency (RF) energy mode. The activation mode may include, for example, cutting, coagulation, or a combination of cutting and coagulation.

[0075] In block 904, the control element determines the waveform of the RF energy based on the selected activation mode of the surgical instrument. As described below, the control element can program the generator 106 using the determined waveform, for example, by storing numerical values ​​or other data representing the determined waveform into the memory of the generator 106.

[0076] In some implementations, in block 906, the control element can change the crest factor (CF) of the RF signal based on a selected activation mode. The crest factor (CF) can be defined as the ratio of the instantaneous peak amplitude of the waveform to its root mean square (RMS) value. The peak amplitude refers to the instantaneous peak voltage that the load may require, while the RMS is the average load voltage under nominal conditions.

[0077] Therefore, CF specifies the characteristics of an electrical system, such as the purity of a signal or waveform, and the system's ability to output a specific current or voltage, such as a power supply. This ratio is also known as the peak-to-RMS ratio and is given by the following formula: Crest factor (CF) = (V 峰值 The ratio of Vrms to Vrms = (Vrms) 峰值 ) / (Vrms value).

[0078] The CF indicator represents the extreme peak value of the waveform. For a pure DC system with a resistive load, this value should be 1:1, which is also the minimum. A pure sine wave has a crest factor. Therefore, in some implementations, the waveform may have a default CF of approximately 1.4, corresponding to a sine waveform.

[0079] In some implementations, in block 908, the control element may be increased for the CF used in solidification. The solidification waveform may be characterized by extensive wave modulation, which produces intermittent pulse trains of damped sine waves with high peak voltages (see, for example...). Figure 10 These peak voltages result in high tissue temperatures and thus significant thermal damage, making this type of waveform particularly suitable for the coagulation of bleeding vessels. Due to its high peak voltage and zero output cycle, this waveform inherently has the highest CF and therefore performs best in achieving coagulation.

[0080] In some embodiments, in block 910, the control element may reduce the CF used for cutting compared to the CF used for solidification. For example, in an exemplary embodiment, the cutting waveform uses a pure, unmodulated sine wave (see...). Figure 10 ), where CF is approximately This waveform achieves the highest average power compared to any other alternating waveform with an equal peak voltage, thus allowing for voltage limiting when compared to the freezing voltage. The high average power generates a higher current density than other waveforms, facilitating a smooth cutting action without extensive thermal damage.

[0081] In some implementations, in block 912, a control element can generate a waveform that blends the coagulation and cutting waveforms. The blended waveform allows the surgeon to cleanly dissect tissue while maintaining varying degrees of hemostasis depending on the amount of coagulation waveform used. One method for generating the blended waveform is by modulating a second, lower-frequency, higher-amplitude sine wave with a sine wave from the cutting generator, thereby generating a higher inter-peak voltage. The newly constructed waveform is then delivered in intermittent pulse trains at a rate determined by the settings of the electrosurgical generator (see, for example,...). Figure 10 Although delivered at a higher peak-to-peak voltage, this pulse train effect contains a lower average power than a pure sine wave due to its duty cycle. Because of its high peak voltage and non-zero output period, the waveform inherently has a cross-flow rate (CF) between that of a pure sine wave and that achieved by a solidified waveform. Therefore, the waveform can produce a cut-out "mixed" effect while maintaining a certain level of solidification.

[0082] By controlling the CF as described above, tissue effects can be controlled to balance cutting and coagulation, achieving the desired tissue effect while minimizing unintended thermal damage. Traditionally, the treatment output waveform has been a continuous sine wave with a CF of approximately 1.4 (including small variations due to amplifier distortion and other signal impurities). Exemplary techniques can dynamically alter waveforms with CF values ​​ranging from approximately 1.4 to much larger values ​​(e.g., up to 6, 7, or 9). Therefore, the described techniques improve container sealing while also reducing cutting time.

[0083] In block 914, the control element and / or generator 106 generates an analog output signal based on the determined waveform. In some embodiments, in block 916, direct digital synthesis can be used to output the waveform from data in memory. In one exemplary embodiment, a block of 2048 addresses in the generator 106 memory is loaded with 2048 values, each representing a unique point on the desired waveform. Another mechanism in the generator continuously scans the addresses of the memory block, retrieving each of the 2048 values ​​stored in the memory one at a time, and also feeding these values ​​one at a time to a digital-to-analog converter (DAC). The DAC then converts each value into a voltage level corresponding to each mentioned value. In this way, the desired waveform is synthesized. It is worth noting that, in order to achieve the desired output frequency, the entire memory block of 2048 values ​​is scanned at a time interval "t" of the desired output frequency "f", where: t = 1 / f.

[0084] As described above, the waveform generated for monopolar or bipolar electrosurgery can be sinusoidal and / or may have other waveforms. In addition, or alternatively, the waveform can be dynamically changed or otherwise updated during activation. In block 918, the control element determines whether to update the waveform. If not, method 900 loops back to block 914 to continue generating the selected waveform. If the control element determines to update the waveform, method 900 proceeds to block 920, where the control element determines the updated waveform based on one or more electrical characteristics of the tissue between the jaws of the end effector. For example, in one embodiment, each memory address in the block may be initially loaded with a value representing a sinusoidal waveform with a CF of approximately 1.4. The value of the memory block can be dynamically modified, for example, by increasing the CF based on the measured electrical characteristics of the tissue. The measured electrical characteristics may include, for example, impedance, impedance change, or other electrical characteristics. After the waveform is updated, for example by changing the value representing the waveform in memory, method 900 loops back to block 914 to continue generating the selected waveform.

[0085] See now Figure 10 Figure 1000 illustrates exemplary waveforms that can be generated according to method 900. Curve 1002 represents a cut waveform, which is illustratively sinusoidal and therefore has a CF of approximately 1.4. Curve 1004 represents a solidified waveform, which illustratively includes a pulse train of a damped sinusoidal signal. Therefore, curve 1004 has a higher CF than curve 1002. Curve 1006 represents a mixed cut / solidified waveform, which can be generated by combining aspects of curves 1002 and 1004. For example, curve 1006 includes a pulse train of a damped sinusoidal signal mixed with a continuous sinusoidal signal and can be generated by modulating a sine wave with another sine wave of a lower frequency.

[0086] In some implementations, multiple waveforms such as Figure 10 The waveforms shown can be used to identify various types of tissue between the jaws of the end effector 120. For example, the frequency response of various tissue types to various types of waveforms can be determined empirically. After determining those frequency responses, in order to perform tissue identification, the control element can program the generator 106 with those various waveforms in a certain sequence (e.g., by storing values ​​representing the corresponding waveforms in the memory of the generator 106). The control element then applies energy with those corresponding waveforms in sequence and measures the frequency response of the tissue between the jaws. The control element can compare the measured frequency response of the tissue between the jaws with predetermined empirical results to identify the type of tissue clamped between the jaws.

[0087] See now Figure 11 A method 1100 for controlling an energy-based surgical instrument 102 is illustrated. Method 1100 may be performed by a controller 702, a generator 106, and / or one or more other microcontrollers or other control elements of system 100. Method 1100 may be performed, for example, in combination with combined RF and ultrasonic operations of the surgical instrument 102. Method 1100 begins at block 1102, where the control element measures the baseline acoustic impedance of the surgical instrument 102 using a subtherapeutic ultrasound signal. Subtherapeutic ultrasound energy (sometimes referred to as subtherapeutic harmonic energy (SAN)) corresponds to the current in which the end effector displacement of the ultrasonic scalpel 130 does not damage the fully clamped tissue. In some embodiments, the subtherapeutic ultrasound signal may be delivered at any time when the user does not request ultrasound energy, such as during RF firing and / or during device idle time. For example, the baseline acoustic impedance may be measured during device idle time when the jaws of the end effector 120 are empty.

[0088] In box 1104, surgical instrument 102 completes an RF energy cycle (e.g., sealing or sealing and slicing). The RF energy cycle may be performed in response to a user request and may include bipolar and / or unipolar operation of surgical instrument 102. The RF energy cycle may, for example, be performed for a predetermined time or until an exit condition is met.

[0089] In block 1106, when the clamping pressure in the jaws of the end effector 120 is released, the control element measures the change in acoustic impedance. The clamping pressure may be released, for example, in response to a user releasing pressure on the closing handle or otherwise commanding the surgical instrument to release pressure after an RF energy cycle. As further described below, the acoustic impedance response of the end effector decreases when pressure is released from the jaws of the end effector.

[0090] In block 1108, the control element determines whether tissue is adhered to the end effector based on the measured impedance change. When STHE is used with ultrasound device 102, there is a correlation between the force acting on the acoustic system and the impedance measured on the acoustic system. For example, system 100 may exhibit a linear trend of increasing impedance with increasing force (e.g., clamping pressure). Impedance response has been found to be sufficiently sensitive to depict the pressure of the fully clamped state, the open state, and the open state with tissue adhesion. In one embodiment, the control element determines whether tissue is adhered to the end effector by comparing the measured acoustic impedance to a baseline acoustic impedance. If the impedance is higher than the baseline (e.g., exceeding a predetermined baseline threshold or otherwise exceeding the baseline), the control element determines that tissue is adhered to the end effector. Alternatively or additionally, in one embodiment, the control element determines whether tissue is adhered to the end effector by comparing the measured acoustic impedance to a baseline acoustic impedance as described above and by determining whether a closing switch is in the open position. As described above, a fully closing switch may be located in device 102 to inform generator 106 when the user has fully or substantially compressed the closing handle. When the user releases pressure on the closing handle, the closing switch can move to the "open" position. Alternatively, in one embodiment, the control element determines whether tissue is stuck to the end actuator based on the absolute value of the measured acoustic impedance (e.g., by comparing the measured value with a predetermined threshold level or other comparison).

[0091] In block 1110, the control element checks whether an automatic ultrasonic release cycle, sometimes referred to as automatic harmonic release (AHR), is activated. If the control element determines that tissue is stuck in the jaws, it may activate the automatic ultrasonic release cycle. As described above, the control element may compare a measured impedance change with a calibration value (e.g., baseline acoustic impedance) to determine whether tissue is still present in the jaws and whether the AHR should be activated. Alternatively or additionally, the change in STHE impedance may be calculated and compared after an RF firing and when the closed switch sensor moves to the “open” position. Alternatively or additionally, in some embodiments, the absolute value of the STHE impedance may be used to trigger the AHR after each RF firing. If the control element determines that the AHR is not activated, method 1100 completes. If the control element determines that the AHR is activated, method 1100 proceeds to block 1112.

[0092] In block 1112, the control element activates the automatic ultrasonic release cycle ultrasonic signal. The ultrasonic release cycle provides a relatively small amount of ultrasonic energy to the blade 130 to reduce tissue adhesion to the end effector. After the automatic ultrasonic release cycle is performed, method 1100 is complete. Surgical instrument 102 can be used to perform additional surgical procedures (e.g., additional cutting or coagulation procedures using RF and / or ultrasonic energy). Thus, as described above, method 1100 prevents AHR from being performed when pressure is present in the jaws of the end effector, thereby avoiding transverse cutting of tissue during the AHR procedure. Therefore, method 1100 mitigates the risk of accidental transverse cutting while eliminating the "wait time" variable and eliminating the need for additional hardware sensors.

[0093] See now Figure 12 Figure 1200 illustrates the correlation between the force acting on the acoustic system and the acoustic impedance measured on the acoustic system for an illustrative end effector. As shown, in the illustrative embodiment, system 100 exhibits a linear trend in acoustic impedance increasing with increasing force (e.g., increasing clamping pressure). Other embodiments also exhibit a similar linear trend in impedance increasing with increasing force, even with different loading paths and magnitudes.

[0094] See now Figure 13 Figure 1300 shows the impedance response of system 100 measured using subtherapeutic harmonic impedance sensing. Figure 1300 shows the baseline impedance 1302, the impedance 1304 with the jaws fully closed and tissue in the jaws, the impedance 1306 with the jaws open and tissue adhered, and the impedance 1308 with the jaws open in the air. As shown, the impedance 1306 in the case of tissue adhesion is higher than the baseline impedance 1302.

[0095] As described above, subtherapeutic signals can be incorporated into the triggering of Automatic Harmonic Release (AHR) in various situations. For example, after the RF energy cycle is complete, the impedance measured by STHE is baselined. As pressure is released from the jaws of the end effector, the impedance response decreases. The increment in impedance can be compared to a calibration value to determine whether tissue remains in the jaws and whether the AHR should be activated. As another example, the increment in STHE impedance can be calculated and compared after the RF firing and the closing switch sensor moves to "on". As yet another example, the absolute value of the STHE impedance can be used to trigger the AHR after each RF firing.

[0096] Although the present disclosure has been illustrated and described in detail in the accompanying drawings and the foregoing description, such illustrations and descriptions should be regarded as exemplary rather than restrictive in nature, and it should be understood that only exemplary embodiments are shown and described, and all changes and modifications made within the substance of the present disclosure should be protected.

[0097] The methods, apparatus, and systems described herein possess numerous advantages due to their various features. It should be noted that alternative embodiments of the methods, apparatus, and systems of this disclosure may exclude all described features, but may still benefit from at least some of the advantages of such features. Those skilled in the art will readily conceive of their own implementations of the methods, apparatus, and systems described above, which may incorporate one or more features of the invention and fall within the spirit and scope of this disclosure as defined by the appended claims.

Claims

1. A method for controlling a surgical instrument, the method comprising: A first energy signal is activated at a sub-therapeutic level by a control element, wherein the first energy signal is output by a surgical generator coupled to the surgical instrument, and wherein the surgical instrument includes an end effector configured to deliver energy to the patient's tissue. The system response to activating the first energy signal is measured by the control element; The activation parameters are determined by the control element based on the system response; and The control element activates a second energy signal at a therapeutic level according to the activation parameters, wherein the second energy signal is output by the surgical generator.

2. The method of claim 1, wherein, The first energy signal includes an ultrasonic signal or a radio frequency (RF) signal; and the second energy signal includes an ultrasonic signal or a radio frequency (RF) signal.

3. The method of claim 1, wherein, The system response includes impedance, rate of change of impedance, or acoustic impedance.

4. The method of claim 1, wherein, The activation parameters include power, current, or duration.

5. A method for controlling a surgical instrument, the method comprising: The activation mode of the surgical instrument is determined by a control element of the surgical instrument, wherein the surgical instrument includes an end effector having a first electrode configured to deliver radio frequency (RF) energy to the patient's tissue; The control element determines the waveform of the energy signal based on the activation mode; In response to determining the waveform, the control element programs the electrosurgical generator coupled to the surgical instrument using the waveform; and In response to programming the electrosurgical generator, the electrosurgical generator delivers the energy signal to the electrodes of the end effector.

6. The method of claim 5, wherein, The activation mode includes a cutting mode, a solidification mode, or a mixing mode, and wherein determining the waveform includes determining the peak factor of the waveform based on the activation mode.

7. The method of claim 6, wherein, Determining the waveform includes determining a first waveform having a first crest factor corresponding to a sine waveform when the activation mode is the cutting mode.

8. The method of claim 7, wherein, Determining the waveform includes determining a second waveform with a second crest factor when the activation mode is the solidification mode, the second crest factor being greater than the first crest factor.

9. The method of claim 8, wherein, The second waveform includes a pulse train of damped sine waves.

10. The method of claim 8, wherein, Determining the waveform includes, when the activation mode is the mixed mode, determining a third waveform with a third peak factor, the third peak factor being between the first peak factor and the second peak factor.

11. The method of claim 10, wherein, The third waveform includes a sine wave modulated with a second, lower frequency sine wave.

12. The method of claim 5, wherein, Delivering the energy signal includes generating an analog output signal of the energy signal using direct digital synthesis.

13. The method of claim 12, wherein, Programming involves storing digital values ​​indicating the waveform in the memory of the electrosurgical generator.

14. The method according to claim 5, further comprising: The control element determines the updated waveform of the energy signal based on the electrical characteristics of the tissue sensed by the end effector; as well as The control element uses the updated waveform to update the programming of the electrosurgical generator.

15. The method of claim 14, wherein, Determining the updated waveform involves adding the crest factor of the waveform to a predetermined crest factor associated with the sine waveform.

16. A method for controlling a surgical instrument, the method comprising: When pressure is applied in the jaws of the surgical instrument, radio frequency (RF) energy is cycled by the surgical instrument using the first electrode of the end effector of the surgical instrument; After performing the RF energy cycle, the pressure in the jaws of the surgical instrument is released; After the pressure in the jaws of the surgical instrument is released, the control element uses the ultrasonic scalpel of the end effector to measure the first acoustic impedance of the surgical instrument using sub-therapeutic ultrasound signals; The control element determines whether tissue adheres to the jaws of the surgical instrument based on the first acoustic impedance; as well as In response to determining that tissue has adhered to the jaws of the surgical instrument, the control element activates an automatic ultrasonic energy release cycle using the ultrasonic scalpel of the surgical instrument.

17. The method according to claim 16, further comprising: The baseline acoustic impedance of the surgical instrument is measured by the control element using the sub-therapeutic ultrasound signal; Determining whether the tissue is stuck includes comparing the first acoustic impedance with the baseline acoustic impedance.

18. The method of claim 17, wherein, Determining whether the tissue is stuck also includes determining whether the closing switch of the surgical instrument has moved to the open position.

19. The method of claim 16, wherein, Determining whether the tissue is stuck includes determining whether the tissue is stuck based on the absolute value of the first acoustic impedance.

20. The method of claim 16, further comprising, during the RF energy cycle or during device idle time, measuring the acoustic impedance of the surgical instrument by the control element using the subtherapeutic ultrasound signal.

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