Patent Description:
Ultrasonic surgical instruments are finding increasingly widespread applications in surgical procedures by virtue of the unique performance characteristics of such instruments. Depending upon specific instrument configurations and operational parameters, ultrasonic surgical instruments can provide substantially simultaneous cutting of tissue and hemostasis by coagulation, desirably minimizing patient trauma. The cutting action is typically realized by an-end effector, or blade tip, at the distal end of the instrument, which transmits ultrasonic energy to tissue brought into contact with the end effector. Ultrasonic instruments of this nature can be configured for open surgical use, laparoscopic, or endoscopic surgical procedures including robotic-assisted procedures.

Some surgical instruments utilize ultrasonic energy for both precise cutting and controlled coagulation. Ultrasonic energy cuts and coagulates by using lower temperatures than those used by electrosurgery. Vibrating at high frequencies (e.g., <NUM>,<NUM> times per second), the ultrasonic blade denatures protein in the tissue to form a sticky coagulum. Pressure exerted on tissue with the blade surface collapses blood vessels and allows the coagulum to form a hemostatic seal. The precision of cutting and coagulation is controlled by the surgeon's technique and adjusting the power level, blade edge, tissue traction, and blade pressure.

Electrosurgical devices for applying electrical energy to tissue in order to treat and/or destroy the tissue are also finding increasingly widespread applications in surgical procedures. An electrosurgical device typically includes a hand piece, an instrument having a distally-mounted end effector (e.g., one or more electrodes). The end effector can be positioned against the tissue such that electrical current is introduced into the tissue. Electrosurgical devices can be configured for bipolar or monopolar operation. During bipolar operation, current is introduced into and returned from the tissue by active and return electrodes, respectively, of the end effector. During monopolar operation, current is introduced into the tissue by an active electrode of the end effector and returned through a return electrode (e.g., a grounding pad) separately located on a patient's body. Heat generated by the current flowing through the tissue may form hemostatic seals within the tissue and/or between tissues and thus may be particularly useful for sealing blood vessels, for example. The end effector of an electrosurgical device may also include a cutting member that is movable relative to the tissue and the electrodes to transect the tissue.

Electrical energy applied by an electrosurgical device can be transmitted to the instrument by a generator in communication with the hand piece. The electrical energy may be in the form of radio frequency ("RF") energy. RF energy is a form of electrical energy that may be in the frequency range of <NUM> kilohertz (kHz) to <NUM> megahertz (MHz). In application, an electrosurgical device can transmit low frequency RF energy through tissue, which causes ionic agitation, or friction, in effect resistive heating, thereby increasing the temperature of the tissue. Because a sharp boundary is created between the affected tissue and the surrounding tissue, surgeons can operate with a high level of precision and control, without sacrificing un-targeted adjacent tissue. The low operating temperatures of RF energy is useful for removing, shrinking, or sculpting soft tissue while simultaneously sealing blood vessels. RF energy works particularly well on connective tissue, which is primarily comprised of collagen and shrinks when contacted by heat.

A challenge of using these medical devices is the inability to control and customize the power output depending on the type of procedures being performed. <CIT> describes a surgical instrument in which a generator may control the amount of power delivered to tissue as the impedance of the tissue changes and control the power delivery to maintain a constant rate of tissue impedance increase. <CIT> describes a processor for executing program instructions for monitoring various measurable characteristics of an ultrasonic surgical instrument and generating a step function output signal for driving the ultrasonic transducer in cutting and/or coagulation operating modes. Monitored characteristics may comprise, for example, transducer impedance, tissue impedance, tissue heating, tissue transection, tissue coagulation, and the like. It would be desirable to provide a surgical instrument that overcomes some of the deficiencies of current instruments. The surgical system described herein overcomes those deficiencies.

The novel features of the described forms are set forth with particularity in the appended claims. The described forms, however, both as to organization and methods of operation, may be best understood by reference to the following description, taken in conjunction with the accompanying drawings in which:.

Before explaining various forms of ultrasonic surgical instruments in detail, it should be noted that the illustrative forms are not limited in application or use to the details of construction and arrangement of parts illustrated in the accompanying drawings and description. The illustrative forms may be implemented or incorporated in other forms, variations and modifications, and may be practiced or carried out in various ways. Further, unless otherwise indicated, the terms and expressions employed herein have been chosen for the purpose of describing the illustrative forms for the convenience of the reader and are not for the purpose of limitation thereof.

Further, it is understood that any one or more of the following-described forms, expressions of forms, examples, can be combined with any one or more of the other following-described forms, expressions of forms, and examples.

Various forms are directed to improved ultrasonic surgical instruments configured for effecting tissue dissecting, cutting, and/or coagulation during surgical procedures. In one form, an ultrasonic surgical instrument apparatus is configured for use in open surgical procedures, but has applications in other types of surgery, such as laparoscopic, endoscopic, and robotic-assisted procedures. Versatile use is facilitated by selective use of ultrasonic energy.

The various forms will be described in combination with an ultrasonic instrument as described herein. Such description is provided by way of example, and not limitation, and is not intended to limit the scope and applications thereof. For example, any one of the described forms is useful in combination with a multitude of ultrasonic instruments including those described in, for example, <CIT>; <CIT>; <CIT>; <CIT>; <CIT>; and <CIT>.

As will become apparent from the following description, it is contemplated that forms of the surgical instrument described herein may be used in association with an oscillator unit of a surgical system, whereby ultrasonic energy from the oscillator unit provides the desired ultrasonic actuation for the present surgical instrument. It is also contemplated that forms of the surgical instrument described herein may be used in association with a signal generator unit of a surgical system, whereby electrical energy in the form of radio frequencies (RF), for example, is used to provide feedback to the user regarding the surgical instrument. The ultrasonic oscillator and/or the signal generator unit may be non-detachably integrated with the surgical instrument or may be provided as separate components, which can be electrically attachable to the surgical instrument.

One form of the present surgical apparatus is particularly configured for disposable use by virtue of its straightforward construction. However, it is also contemplated that other forms of the present surgical instrument can be configured for non-disposable or multiple uses. Detachable connection of the present surgical instrument with an associated oscillator and signal generator unit is presently disclosed for single-patient use for illustrative purposes only. However, non-detachable integrated connection of the present surgical instrument with an associated oscillator and/or signal generator unit is also contemplated. Accordingly, various forms of the presently described surgical instruments may be configured for single use and/or multiple use with either detachable and/or non-detachable integral oscillator and/or signal generator unit, without limitation, and all combinations of such configurations are contemplated to be within the scope of the present disclosure.

With reference to <FIG>, one form of a surgical system <NUM> including an ultrasonic surgical instrument is illustrated. <FIG> illustrates one form of a surgical system <NUM> comprising a generator <NUM> and various surgical instruments <NUM>, <NUM> usable therewith. <FIG> is a diagram of the ultrasonic surgical instrument <NUM> of <FIG>. The generator <NUM> is configurable for use with surgical devices. According to various forms, the generator <NUM> may be configurable for use with different surgical devices of different types including, for example, the ultrasonic device <NUM> and electrosurgical or RF surgical devices, such as, the RF device <NUM>. Although in the form of <FIG>, the generator <NUM> is shown separate from the surgical devices <NUM>, <NUM>, in one form, the generator <NUM> may be formed integrally with either of the surgical devices <NUM>, <NUM> to form a unitary surgical system. The generator <NUM> comprises an input device <NUM> located on a front panel of the generator <NUM> console. The input device <NUM> may comprise any suitable device that generates signals suitable for programming the operation of the generator <NUM>.

<FIG> is a diagram of the surgical system <NUM> of <FIG>. In various forms, the generator <NUM> may comprise several separate functional elements, such as modules and/or blocks. Different functional elements or modules may be configured for driving the different kinds of surgical devices <NUM>, <NUM>. For example, an ultrasonic generator module <NUM> may drive ultrasonic devices such as the ultrasonic device <NUM>. An electrosurgery/RF generator module <NUM> may drive the electrosurgical device <NUM>. For example, the respective modules <NUM>, <NUM> may generate respective drive signals for driving the surgical devices <NUM>, <NUM>. In various forms, the ultrasonic generator module <NUM> and/or the electrosurgery/RF generator module <NUM> each may be formed integrally with the generator <NUM>. Alternatively, one or more of the modules <NUM>, <NUM> may be provided as a separate circuit module electrically coupled to the generator <NUM>. (The modules <NUM> and <NUM> are shown in phantom to illustrate this option. ) Also, in some forms, the electrosurgery/RF generator module <NUM> may be formed integrally with the ultrasonic generator module <NUM>, or vice versa. Also, in some forms, the generator <NUM> may be omitted entirely and the modules <NUM>, <NUM> may be executed by processors or other hardware within the respective instruments <NUM>, <NUM>.

In accordance with the described forms, the ultrasonic generator module <NUM> may produce a drive signal or signals of particular voltages, currents, and frequencies, e.g., <NUM>,<NUM> cycles per second (Hz). The drive signal or signals may be provided to the ultrasonic device <NUM>, and specifically to the transducer <NUM>, which may operate, for example, as described above. The transducer <NUM> and a waveguide extending through the shaft <NUM> (waveguide not shown in <FIG>) may collectively form an ultrasonic drive system driving an ultrasonic blade <NUM> of an end effector <NUM>. In one form, the generator <NUM> may be configured to produce a drive signal of a particular voltage, current, and/or frequency output signal that can be stepped or otherwise modified with high resolution, accuracy, and repeatability.

The generator <NUM> may be activated to provide the drive signal to the transducer <NUM> in any suitable manner. For example, the generator <NUM> may comprise a foot switch <NUM> coupled to the generator <NUM> via a footswitch cable <NUM>. A clinician may activate the transducer <NUM> by depressing the foot switch <NUM>. In addition, or instead of the foot switch <NUM> some forms of the ultrasonic device <NUM> may utilize one or more switches positioned on the hand piece that, when activated, may cause the generator <NUM> to activate the transducer <NUM>. In one form, for example, the one or more switches may comprise a pair of toggle buttons 1036a, 1036b (<FIG>), for example, to determine an operating mode of the device <NUM>. When the toggle button 1036a is depressed, for example, the ultrasonic generator <NUM> may provide a maximum drive signal to the transducer <NUM>, causing it to produce maximum ultrasonic energy output. Depressing toggle button 1036b may cause the ultrasonic generator <NUM> to provide a user-selectable drive signal to the transducer <NUM>, causing it to produce less than the maximum ultrasonic energy output. The device <NUM> additionally or alternatively may comprise a second switch (not shown) to, for example, indicate a position of a jaw closure trigger for operating jaws of the end effector <NUM>. Also, in some forms, the ultrasonic generator <NUM> may be activated based on the position of the jaw closure trigger, (e.g., as the clinician depresses the jaw closure trigger to close the jaws, ultrasonic energy may be applied).

Additionally or alternatively, the one or more switches may comprises a toggle button 1036c that, when depressed, causes the generator <NUM> to provide a pulsed output. The pulses may be provided at any suitable frequency and grouping, for example. In certain forms, the power level of the pulses may be the power levels associated with toggle buttons 1036a, 1036b (maximum, less than maximum), for example.

It will be appreciated that a device <NUM> may comprise any combination of the toggle buttons 1036a, 1036b, 1036c. For example, the device <NUM> could be configured to have only two toggle buttons: a toggle button 1036a for producing maximum ultrasonic energy output and a toggle button 1036c for producing a pulsed output at either the maximum or less than maximum power level. In this way, the drive signal output configuration of the generator <NUM> could be <NUM> continuous signals and <NUM> or <NUM> or <NUM> or <NUM> or <NUM> pulsed signals. In certain forms, the specific drive signal configuration may be controlled based upon, for example, EEPROM settings in the generator <NUM> and/or user power level selection(s).

In certain forms, a two-position switch may be provided as an alternative to a toggle button 1036c. For example, a device <NUM> may include a toggle button 1036a for producing a continuous output at a maximum power level and a two-position toggle button 1036b. In a first detented position, toggle button 1036b may produce a continuous output at a less than maximum power level, and in a second detented position the toggle button 1036b may produce a pulsed output (e.g., at either a maximum or less than maximum power level, depending upon the EEPROM settings).

In accordance with the described forms, the electrosurgery/RF generator module <NUM> may generate a drive signal or signals with output power sufficient to perform bipolar electrosurgery using radio frequency (RF) energy. In bipolar electrosurgery applications, the drive signal may be provided, for example, to electrodes of the electrosurgical device <NUM>, for example. Accordingly, the generator <NUM> may be configured for therapeutic purposes by applying electrical energy to the tissue sufficient for treating the tissue (e.g., coagulation, cauterization, tissue welding).

The generator <NUM> may comprise an input device <NUM> (<FIG>) located, for example, on a front panel of the generator <NUM> console. The input device <NUM> may comprise any suitable device that generates signals suitable for programming the operation of the generator <NUM>. In operation, the user can program or otherwise control operation of the generator <NUM> using the input device <NUM>. The input device <NUM> may comprise any suitable device that generates signals that can be used by the generator (e.g., by one or more processors contained in the generator) to control the operation of the generator <NUM> (e.g., operation of the ultrasonic generator module <NUM> and/or electrosurgery/RF generator module <NUM>). In various forms, the input device <NUM> includes one or more of buttons, switches, thumbwheels, keyboard, keypad, touch screen monitor, pointing device, remote connection to a general purpose or dedicated computer. In other forms, the input device <NUM> may comprise a suitable user interface, such as one or more user interface screens displayed on a touch screen monitor, for example. Accordingly, by way of the input device <NUM>, the user can set or program various operating parameters of the generator, such as, for example, current (I), voltage (V), frequency (f), and/or period (T) of a drive signal or signals generated by the ultrasonic generator module <NUM> and/or electrosurgery/RF generator module <NUM>.

The generator <NUM> may also comprise an output device <NUM> (<FIG>), such as an output indicator, located, for example, on a front panel of the generator <NUM> console. The output device <NUM> includes one or more devices for providing a sensory feedback to a user. Such devices may comprise, for example, visual feedback devices (e.g., a visual feedback device may comprise incandescent lamps, light emitting diodes (LEDs), graphical user interface, display, analog indicator, digital indicator, bar graph display, digital alphanumeric display, LCD display screen, LED indicators), audio feedback devices (e.g., an audio feedback device may comprise speaker, buzzer, audible, computer generated tone, computerized speech, voice user interface (VUI) to interact with computers through a voice/speech platform), or tactile feedback devices (e.g., a tactile feedback device comprises any type of vibratory feedback, haptic actuator).

Although certain modules and/or blocks of the generator <NUM> may be described by way of example, it can be appreciated that a greater or lesser number of modules and/or blocks may be used and still fall within the scope of the forms. Further, although various forms may be described in terms of modules and/or blocks to facilitate description, such modules and/or blocks may be implemented by one or more hardware components, e.g., processors, Digital Signal Processors (DSPs), Programmable Logic Devices (PLDs), Application Specific Integrated Circuits (ASICs), circuits, registers and/or software components, e.g., programs, subroutines, logic and/or combinations of hardware and software components. Also, in some forms, the various modules described herein may be implemented utilizing similar hardware positioned within the instruments <NUM>, <NUM> (i.e., the generator <NUM> may be omitted).

In one form, the ultrasonic generator drive module <NUM> and electrosurgery/RF drive module <NUM> may comprise one or more embedded applications implemented as firmware, software, hardware, or any combination thereof. The modules <NUM>, <NUM> may comprise various executable modules such as software, programs, data, drivers, application program interfaces (APIs), and so forth. The firmware may be stored in nonvolatile memory (NVM), such as in bit-masked read-only memory (ROM) or flash memory. In various implementations, storing the firmware in ROM may preserve flash memory. The NVM may comprise other types of memory including, for example, programmable ROM (PROM), erasable programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), or battery backed random-access memory (RAM) such as dynamic RAM (DRAM), Double-Data-Rate DRAM (DDRAM), and/or synchronous DRAM (SDRAM).

In one form, the modules <NUM>, <NUM> comprise a hardware component implemented as a processor for executing program instructions for monitoring various measurable characteristics of the devices <NUM>, <NUM> and generating a corresponding output control signals for operating the devices <NUM>, <NUM>. In forms in which the generator <NUM> is used in conjunction with the device <NUM>, the output control signal may drive the ultrasonic transducer <NUM> in cutting and/or coagulation operating modes. Electrical characteristics of the device <NUM> and/or tissue may be measured and used to control operational aspects of the generator <NUM> and/or provided as feedback to the user. In forms in which the generator <NUM> is used in conjunction with the device <NUM>, the output control signal may supply electrical energy (e.g., RF energy) to the end effector <NUM> in cutting, coagulation and/or desiccation modes. Electrical characteristics of the device <NUM> and/or tissue may be measured and used to control operational aspects of the generator <NUM> and/or provide feedback to the user. In various forms, as previously discussed, the hardware component may be implemented as a DSP, PLD, ASIC, circuits, and/or registers. In one form, the processor may be configured to store and execute computer software program instructions to generate the step function output signals for driving various components of the devices <NUM>, <NUM>, such as the ultrasonic transducer <NUM> and the end effectors <NUM>, <NUM>.

<FIG> illustrates an equivalent circuit <NUM> of an ultrasonic transducer, such as the ultrasonic transducer <NUM>, according to one form. The circuit <NUM> comprises a first "motional" branch having a serially connected inductance Ls, resistance Rs and capacitance Cs that define the electromechanical properties of the resonator, and a second capacitive branch having a static capacitance Co. Drive current Ig may be received from a generator at a drive voltage Vg, with motional current Im flowing through the first branch and current Ig - Im flowing through the capacitive branch. Control of the electromechanical properties of the ultrasonic transducer may be achieved by suitably controlling Ig and Vg. As explained above, conventional generator architectures may include a tuning inductor Lt (shown in phantom in <FIG>) for tuning out in a parallel resonance circuit the static capacitance Co at a resonant frequency so that substantially all of generator's current output Ig flows through the motional branch. In this way, control of the motional branch current Im is achieved by controlling the generator current output Ig. The tuning inductor Lt is specific to the static capacitance Co of an ultrasonic transducer, however, and a different ultrasonic transducer having a different static capacitance requires a different tuning inductor Lt. Moreover, because the tuning inductor Lt is matched to the nominal value of the static capacitance Co at a single resonant frequency, accurate control of the motional branch current Im is assured only at that frequency, and as frequency shifts down with transducer temperature, accurate control of the motional branch current is compromised.

Forms of the generator <NUM> do not rely on a tuning inductor Lt to monitor the motional branch current Im. Instead, the generator <NUM> may use the measured value of the static capacitance Co in between applications of power for a specific ultrasonic surgical device <NUM> (along with drive signal voltage and current feedback data) to determine values of the motional branch current Im on a dynamic and ongoing basis (e.g., in real-time). Such forms of the generator <NUM> are therefore able to provide virtual tuning to simulate a system that is tuned or resonant with any value of static capacitance Co at any frequency, and not just at single resonant frequency dictated by a nominal value of the static capacitance Co.

<FIG> is a simplified block diagram of one form of the generator <NUM> for proving inductorless tuning as described above, among other benefits. Additional details of the generator <NUM> are described in commonly assigned <CIT>, entitled "Surgical Generator For Ultrasonic And Electrosurgical Devices," now <CIT>. With reference to <FIG>, the generator <NUM> may comprise a patient isolated stage <NUM> in communication with a non-isolated stage <NUM> via a power transformer <NUM>. A secondary winding <NUM> of the power transformer <NUM> is contained in the isolated stage <NUM> and may comprise a tapped configuration (e.g., a center-tapped or a non-center-tapped configuration) to define drive signal outputs 1060a, 1060b, 1060c for outputting drive signals to different surgical devices, such as, for example, an ultrasonic surgical device <NUM> and an electrosurgical device <NUM>. In particular, drive signal outputs 1060a, 1060c may output an ultrasonic drive signal (e.g., a 420V RMS drive signal) to an ultrasonic surgical device <NUM>, and drive signal outputs 1060b, 1060c may output an electrosurgical drive signal (e.g., a 100V RMS drive signal) to an electrosurgical device <NUM>, with output 1060b corresponding to the center tap of the power transformer <NUM>.

In certain forms, the ultrasonic and electrosurgical drive signals may be provided simultaneously to distinct surgical instruments and/or to a single surgical instrument having the capability to deliver both ultrasonic and electrosurgical energy to tissue. It will be appreciated that the electrosurgical signal, provided either to a dedicated electrosurgical instrument and/or to a combined ultrasonic/electrosurgical instrument may be either a therapeutic or sub-therapeutic level signal.

The non-isolated stage <NUM> may comprise a power amplifier <NUM> having an output connected to a primary winding <NUM> of the power transformer <NUM>. In certain forms the power amplifier <NUM> may be comprise a push-pull amplifier. For example, the non-isolated stage <NUM> may further comprise a logic device <NUM> for supplying a digital output to a digital-to-analog converter (DAC) <NUM>, which in turn supplies a corresponding analog signal to an input of the power amplifier <NUM>. In certain forms the logic device <NUM> may comprise a programmable gate array (PGA), a field-programmable gate array (FPGA), programmable logic device (PLD), among other logic circuits, for example. The logic device <NUM>, by virtue of controlling the input of the power amplifier <NUM> via the DAC <NUM>, may therefore control any of a number of parameters (e.g., frequency, waveform shape, waveform amplitude) of drive signals appearing at the drive signal outputs 1060a, 1060b, 1060c. In certain forms and as discussed below, the logic device <NUM>, in conjunction with a processor (e.g., a digital signal processor discussed below), may implement a number of digital signal processing (DSP)-based and/or other control algorithms to control parameters of the drive signals output by the generator <NUM>.

Power may be supplied to a power rail of the power amplifier <NUM> by a switch-mode regulator <NUM>. In certain forms the switch-mode regulator <NUM> may comprise an adjustable buck regulator, for example. The non-isolated stage <NUM> may further comprise a first processor <NUM>, which in one form may comprise a DSP processor such as an Analog Devices ADSP-<NUM> SHARC DSP, available from Analog Devices, Norwood, MA, for example, although in various forms any suitable processor may be employed. In certain forms the processor <NUM> may control operation of the switch-mode power converter <NUM> responsive to voltage feedback data received from the power amplifier <NUM> by the DSP processor <NUM> via an analog-to-digital converter (ADC) <NUM>. In one form, for example, the DSP processor <NUM> may receive as input, via the ADC <NUM>, the waveform envelope of a signal (e.g., an RF signal) being amplified by the power amplifier <NUM>. The DSP processor <NUM> may then control the switch-mode regulator <NUM> (e.g., via a pulse-width modulated (PWM) output) such that the rail voltage supplied to the power amplifier <NUM> tracks the waveform envelope of the amplified signal. By dynamically modulating the rail voltage of the power amplifier <NUM> based on the waveform envelope, the efficiency of the power amplifier <NUM> may be significantly improved relative to a fixed rail voltage amplifier schemes.

In certain forms, the logic device <NUM>, in conjunction with the DSP processor <NUM>, may implement a direct digital synthesizer (DDS) control scheme to control the waveform shape, frequency and/or amplitude of drive signals output by the generator <NUM>. In one form, for example, the logic device <NUM> may implement a DDS control algorithm by recalling waveform samples stored in a dynamically-updated look-up table (LUT), such as a RAM LUT, which may be embedded in an FPGA. This control algorithm is particularly useful for ultrasonic applications in which an ultrasonic transducer, such as the ultrasonic transducer <NUM>, may be driven by a clean sinusoidal current at its resonant frequency. Because other frequencies may excite parasitic resonances, minimizing or reducing the total distortion of the motional branch current may correspondingly minimize or reduce undesirable resonance effects. Because the waveform shape of a drive signal output by the generator <NUM> is impacted by various sources of distortion present in the output drive circuit (e.g., the power transformer <NUM>, the power amplifier <NUM>), voltage and current feedback data based on the drive signal may be input into an algorithm, such as an error control algorithm implemented by the DSP processor <NUM>, which compensates for distortion by suitably pre-distorting or modifying the waveform samples stored in the LUT on a dynamic, ongoing basis (e.g., in real-time). In one form, the amount or degree of pre-distortion applied to the LUT samples may be based on the error between a computed motional branch current and a desired current waveform shape, with the error being determined on a sample-by-sample basis. In this way, the pre-distorted LUT samples, when processed through the drive circuit, may result in a motional branch drive signal having the desired waveform shape (e.g., sinusoidal) for optimally driving the ultrasonic transducer. In such forms, the LUT waveform samples will therefore not represent the desired waveform shape of the drive signal, but rather the waveform shape that is required to ultimately produce the desired waveform shape of the motional branch drive signal when distortion effects are taken into account.

The non-isolated stage <NUM> may further comprise an ADC <NUM> and an ADC <NUM> coupled to the output of the power transformer <NUM> via respective isolation transformers <NUM>, <NUM> for respectively sampling the voltage and current of drive signals output by the generator <NUM>. In certain forms, the ADCs <NUM>, <NUM> may be configured to sample at high speeds (e.g., <NUM> MSPS) to enable oversampling of the drive signals. In one form, for example, the sampling speed of the ADCs <NUM>, <NUM> may enable approximately 200x (depending on frequency) oversampling of the drive signals. In certain forms, the sampling operations of the ADC <NUM>, <NUM> may be performed by a singe ADC receiving input voltage and current signals via a two-way multiplexer. The use of high-speed sampling in forms of the generator <NUM> may enable, among other things, calculation of the complex current flowing through the motional branch (which may be used in certain forms to implement DDS-based waveform shape control described above), accurate digital filtering of the sampled signals, and calculation of real power consumption with a high degree of precision. Voltage and current feedback data output by the ADCs <NUM>, <NUM> may be received and processed (e.g., FIFO buffering, multiplexing) by the logic device <NUM> and stored in data memory for subsequent retrieval by, for example, the DSP processor <NUM>. As noted above, voltage and current feedback data may be used as input to an algorithm for pre-distorting or modifying LUT waveform samples on a dynamic and ongoing basis. In certain forms, this may require each stored voltage and current feedback data pair to be indexed based on, or otherwise associated with, a corresponding LUT sample that was output by the logic device <NUM> when the voltage and current feedback data pair was acquired. Synchronization of the LUT samples and the voltage and current feedback data in this manner contributes to the correct timing and stability of the pre-distortion algorithm.

In certain forms, the voltage and current feedback data may be used to control the frequency and/or amplitude (e.g., current amplitude) of the drive signals. In one form, for example, voltage and current feedback data may be used to determine impedance phase. The frequency of the drive signal may then be controlled to minimize or reduce the difference between the determined impedance phase and an impedance phase setpoint (e.g., <NUM>°), thereby minimizing or reducing the effects of harmonic distortion and correspondingly enhancing impedance phase measurement accuracy. The determination of phase impedance and a frequency control signal may be implemented in the DSP processor <NUM>, for example, with the frequency control signal being supplied as input to a DDS control algorithm implemented by the logic device <NUM>.

In another form, for example, the current feedback data may be monitored in order to maintain the current amplitude of the drive signal at a current amplitude setpoint. The current amplitude setpoint may be specified directly or determined indirectly based on specified voltage amplitude and power setpoints. In certain forms, control of the current amplitude may be implemented by control algorithm, such as, for example, a PID control algorithm, in the processor <NUM>. Variables controlled by the control algorithm to suitably control the current amplitude of the drive signal may include, for example, the scaling of the LUT waveform samples stored in the logic device <NUM> and/or the full-scale output voltage of the DAC <NUM> (which supplies the input to the power amplifier <NUM>) via a DAC <NUM>.

The non-isolated stage <NUM> may further comprise a second processor <NUM> for providing, among other things user interface (UI) functionality. In one form, the UI processor <NUM> may comprise an Atmel AT91SAM9263 processor having an ARM 926EJ-S core, available from Atmel Corporation, San Jose, CA, for example. Examples of UI functionality supported by the UI processor <NUM> may include audible and visual user feedback, communication with peripheral devices (e.g., via a Universal Serial Bus (USB) interface), communication with the footswitch <NUM>, communication with an input device <NUM> (e.g., a touch screen display) and communication with an output device <NUM> (e.g., a speaker). The UI processor <NUM> may communicate with the processor <NUM> and the logic device <NUM> (e.g., via serial peripheral interface (SPI) buses). Although the UI processor <NUM> may primarily support UI functionality, it may also coordinate with the DSP processor <NUM> to implement hazard mitigation in certain forms. For example, the UI processor <NUM> may be programmed to monitor various aspects of user input and/or other inputs (e.g., touch screen inputs, footswitch <NUM> inputs (<FIG>), temperature sensor inputs) and may disable the drive output of the generator <NUM> when an erroneous condition is detected.

In certain forms, both the DSP processor <NUM> and the UI processor <NUM>, for example, may determine and monitor the operating state of the generator <NUM>. For the DSP processor <NUM>, the operating state of the generator <NUM> may dictate, for example, which control and/or diagnostic processes are implemented by the DSP processor <NUM>. For the UI processor <NUM>, the operating state of the generator <NUM> may dictate, for example, which elements of a user interface (e.g., display screens, sounds) are presented to a user. The respective DSP and UI processors <NUM>, <NUM> may independently maintain the current operating state of the generator <NUM> and recognize and evaluate possible transitions out of the current operating state. The DSP processor <NUM> may function as the master in this relationship and determine when transitions between operating states are to occur. The UI processor <NUM> may be aware of valid transitions between operating states and may confirm if a particular transition is appropriate. For example, when the DSP processor <NUM> instructs the UI processor <NUM> to transition to a specific state, the UI processor <NUM> may verify that requested transition is valid. In the event that a requested transition between states is determined to be invalid by the UI processor <NUM>, the UI processor <NUM> may cause the generator <NUM> to enter a failure mode.

The non-isolated stage <NUM> may further comprise a controller <NUM> for monitoring input devices <NUM> (e.g., a capacitive touch sensor used for turning the generator <NUM> on and off, a capacitive touch screen). In certain forms, the controller <NUM> may comprise at least one processor and/or other controller device in communication with the UI processor <NUM>. In one form, for example, the controller <NUM> may comprise a processor (e.g., a Mega168 <NUM>-bit controller available from Atmel) configured to monitor user input provided via one or more capacitive touch sensors. In one form, the controller <NUM> may comprise a touch screen controller (e.g., a QT5480 touch screen controller available from Atmel) to control and manage the acquisition of touch data from a capacitive touch screen.

In certain forms, when the generator <NUM> is in a "power off" state, the controller <NUM> may continue to receive operating power (e.g., via a line from a power supply of the generator <NUM>, such as the power supply <NUM> discussed below). In this way, the controller <NUM> may continue to monitor an input device <NUM> (e.g., a capacitive touch sensor located on a front panel of the generator <NUM>) for turning the generator <NUM> on and off. When the generator <NUM> is in the power off state, the controller <NUM> may wake the power supply (e.g., enable operation of one or more DC/DC voltage converters <NUM> of the power supply <NUM>) if activation of the "on/off" input device <NUM> by a user is detected. The controller <NUM> may therefore initiate a sequence for transitioning the generator <NUM> to a "power on" state. Conversely, the controller <NUM> may initiate a sequence for transitioning the generator <NUM> to the power off state if activation of the "on/off" input device <NUM> is detected when the generator <NUM> is in the power on state. In certain forms, for example, the controller <NUM> may report activation of the "on/off" input device <NUM> to the processor <NUM>, which in turn implements the necessary process sequence for transitioning the generator <NUM> to the power off state. In such forms, the controller <NUM> may have no independent ability for causing the removal of power from the generator <NUM> after its power on state has been established.

In certain forms, the controller <NUM> may cause the generator <NUM> to provide audible or other sensory feedback for alerting the user that a power on or power off sequence has been initiated. Such an alert may be provided at the beginning of a power on or power off sequence and prior to the commencement of other processes associated with the sequence.

In certain forms, the isolated stage <NUM> may comprise an instrument interface circuit <NUM> to, for example, provide a communication interface between a control circuit of a surgical device (e.g., a control circuit comprising hand piece switches) and components of the non-isolated stage <NUM>, such as, for example, the programmable logic device <NUM>, the DSP processor <NUM> and/or the UI processor <NUM>. The instrument interface circuit <NUM> may exchange information with components of the non-isolated stage <NUM> via a communication link that maintains a suitable degree of electrical isolation between the stages <NUM>, <NUM>, such as, for example, an infrared (IR)-based communication link. Power may be supplied to the instrument interface circuit <NUM> using, for example, a low-dropout voltage regulator powered by an isolation transformer driven from the non-isolated stage <NUM>.

In one form, the instrument interface circuit <NUM> may comprise a logic device <NUM> (e.g., logic circuit, programmable logic circuit, PGA, FPGA, PLD) in communication with a signal conditioning circuit <NUM>. The signal conditioning circuit <NUM> may be configured to receive a periodic signal from the logic circuit <NUM> (e.g., a <NUM> square wave) to generate a bipolar interrogation signal having an identical frequency. The interrogation signal may be generated, for example, using a bipolar current source fed by a differential amplifier. The interrogation signal may be communicated to a surgical device control circuit (e.g., by using a conductive pair in a cable that connects the generator <NUM> to the surgical device) and monitored to determine a state or configuration of the control circuit. The control circuit may comprise a number of switches, resistors and/or diodes to modify one or more characteristics (e.g., amplitude, rectification) of the interrogation signal such that a state or configuration of the control circuit is uniquely discernable based on the one or more characteristics. In one form, for example, the signal conditioning circuit <NUM> may comprises an ADC for generating samples of a voltage signal appearing across inputs of the control circuit resulting from passage of interrogation signal therethrough. The logic device <NUM> (or a component of the non-isolated stage <NUM>) may then determine the state or configuration of the control circuit based on the ADC samples.

In one form, the instrument interface circuit <NUM> may comprise a first data circuit interface <NUM> to enable information exchange between the logic circuit <NUM> (or other element of the instrument interface circuit <NUM>) and a first data circuit disposed in or otherwise associated with a surgical device. In certain forms, for example, a first data circuit <NUM> (<FIG>) may be disposed in a cable integrally attached to a surgical device hand piece, or in an adaptor for interfacing a specific surgical device type or model with the generator <NUM>. The data circuit <NUM> may be implemented in any suitable manner and may communicate with the generator according to any suitable protocol including, for example, as described herein with respect to the circuit <NUM>. In certain forms, the first data circuit may comprise a non-volatile storage device, such as an electrically erasable programmable read-only memory (EEPROM) device. In certain forms and referring again to <FIG>, the first data circuit interface <NUM> may be implemented separately from the logic device <NUM> and comprise suitable circuitry (e.g., discrete logic devices, a processor) to enable communication between the programmable logic device <NUM> and the first data circuit. In other forms, the first data circuit interface <NUM> may be integral with the logic device <NUM>.

In certain forms, the first data circuit <NUM> may store information pertaining to the particular surgical device with which it is associated. Such information may include, for example, a model number, a serial number, a number of operations in which the surgical device has been used, and/or any other type of information. This information may be read by the instrument interface circuit <NUM> (e.g., by the logic device <NUM>), transferred to a component of the non-isolated stage <NUM> (e.g., to logic device <NUM>, DSP processor <NUM> and/or UI processor <NUM>) for presentation to a user via an output device <NUM> and/or for controlling a function or operation of the generator <NUM>. Additionally, any type of information may be communicated to first data circuit <NUM> for storage therein via the first data circuit interface <NUM> (e.g., using the logic device <NUM>). Such information may comprise, for example, an updated number of operations in which the surgical device has been used and/or dates and/or times of its usage.

As discussed previously, a surgical instrument may be detachable from a hand piece (e.g., instrument <NUM> may be detachable from hand piece) to promote instrument interchangeability and/or disposability. In such cases, conventional generators may be limited in their ability to recognize particular instrument configurations being used and to optimize control and diagnostic processes accordingly. The addition of readable data circuits to surgical device instruments to address this issue is problematic from a compatibility standpoint, however. For example, designing a surgical device to remain backwardly compatible with generators that lack the requisite data reading functionality may be impractical due to, for example, differing signal schemes, design complexity, and cost. Forms of instruments discussed herein address these concerns by using data circuits that may be implemented in existing surgical instruments economically and with minimal design changes to preserve compatibility of the surgical devices with current generator platforms.

Additionally, forms of the generator <NUM> may enable communication with instrument-based data circuits. For example, the generator <NUM> may be configured to communicate with a second data circuit <NUM> contained in an instrument (e.g., instrument <NUM>) of a surgical device (<FIG>). In some forms, the second data circuit <NUM> may be implemented in a many similar to that of the data circuit <NUM> described herein. The instrument interface circuit <NUM> may comprise a second data circuit interface <NUM> to enable this communication. In one form, the second data circuit interface <NUM> may comprise a tri-state digital interface, although other interfaces may also be used. In certain forms, the second data circuit may generally be any circuit for transmitting and/or receiving data. In one form, for example, the second data circuit may store information pertaining to the particular surgical instrument with which it is associated. Such information may include, for example, a model number, a serial number, a number of operations in which the surgical instrument has been used, and/or any other type of information. In some forms, the second data circuit <NUM> may store information about the electrical and/or ultrasonic properties of an associated transducer <NUM>, end effector <NUM>, or ultrasonic drive system. For example, the first data circuit <NUM> may indicate a burn-in frequency slope, as described herein. Additionally or alternatively, any type of information may be communicated to second data circuit for storage therein via the second data circuit interface <NUM> (e.g., using the logic device <NUM>). Such information may comprise, for example, an updated number of operations in which the instrument has been used and/or dates and/or times of its usage. In certain forms, the second data circuit may transmit data acquired by one or more sensors (e.g., an instrument-based temperature sensor). In certain forms, the second data circuit may receive data from the generator <NUM> and provide an indication to a user (e.g., an LED indication or other visible indication) based on the received data.

In certain forms, the second data circuit and the second data circuit interface <NUM> may be configured such that communication between the logic device <NUM> and the second data circuit can be effected without the need to provide additional conductors for this purpose (e.g., dedicated conductors of a cable connecting a hand piece to the generator <NUM>). In one form, for example, information may be communicated to and from the second data circuit using a <NUM>-wire bus communication scheme implemented on existing cabling, such as one of the conductors used transmit interrogation signals from the signal conditioning circuit <NUM> to a control circuit in a hand piece. In this way, design changes or modifications to the surgical device that might otherwise be necessary are minimized or reduced. Moreover, because different types of communications implemented over a common physical channel can be frequency-band separated, the presence of a second data circuit may be "invisible" to generators that do not have the requisite data reading functionality, thus enabling backward compatibility of the surgical device instrument.

In certain forms, the isolated stage <NUM> may comprise at least one blocking capacitor <NUM>-<NUM> connected to the drive signal output 1060b to prevent passage of DC current to a patient. A single blocking capacitor may be required to comply with medical regulations or standards, for example. While failure in single-capacitor designs is relatively uncommon, such failure may nonetheless have negative consequences. In one form, a second blocking capacitor <NUM>-<NUM> may be provided in series with the blocking capacitor <NUM>-<NUM>, with current leakage from a point between the blocking capacitors <NUM>-<NUM>, <NUM>-<NUM> being monitored by, for example, an ADC <NUM> for sampling a voltage induced by leakage current. The samples may be received by the logic circuit <NUM>, for example. Based changes in the leakage current (as indicated by the voltage samples in the form of <FIG>), the generator <NUM> may determine when at least one of the blocking capacitors <NUM>-<NUM>, <NUM>-<NUM> has failed. Accordingly, the form of <FIG> provides a benefit over single-capacitor designs having a single point of failure.

In certain forms, the non-isolated stage <NUM> may comprise a power supply <NUM> for outputting DC power at a suitable voltage and current. The power supply may comprise, for example, a <NUM> W power supply for outputting a <NUM> VDC system voltage. The power supply <NUM> may further comprise one or more DC/DC voltage converters <NUM> for receiving the output of the power supply to generate DC outputs at the voltages and currents required by the various components of the generator <NUM>. As discussed above in connection with the controller <NUM>, one or more of the DC/DC voltage converters <NUM> may receive an input from the controller <NUM> when activation of the "on/off" input device <NUM> by a user is detected by the controller <NUM> to enable operation of, or wake, the DC/DC voltage converters <NUM>.

Having described operational details of various forms of the surgical system <NUM> (<FIG>) operations for the above surgical system <NUM> may be further described generally in terms of a process for cutting and coagulating tissue employing a surgical instrument comprising an input device <NUM> and the generator <NUM>. Although a particular process is described in connection with the operational details, it can be appreciated that the process merely provides an example of how the general functionality described herein can be implemented by the surgical system <NUM>. Further, the given process does not necessarily have to be executed in the order presented herein unless otherwise indicated. As previously discussed, the input devices <NUM> may be employed to program the output (e.g., impedance, current, voltage, frequency) of the surgical devices <NUM>, <NUM> (<FIG>).

<FIG> illustrates one form of a drive system <NUM> of the generator <NUM>, which creates an ultrasonic electrical signal for driving an ultrasonic transducer, also referred to as a drive signal. The drive system <NUM> is flexible and can create an ultrasonic electrical drive signal <NUM> at a desired frequency and power level setting for driving the ultrasonic transducer <NUM>. In various forms, the generator <NUM> may comprise several separate functional elements, such as modules and/or blocks. Although certain modules and/or blocks may be described by way of example, it can be appreciated that a greater or lesser number of modules and/or blocks may be used and still fall within the scope of the forms. Further, although various forms may be described in terms of modules and/or blocks to facilitate description, such modules and/or blocks may be implemented by one or more hardware components, e.g., processors, Digital Signal Processors (DSPs), Programmable Logic Devices (PLDs), Application Specific Integrated Circuits (ASICs), circuits, registers and/or software components, e.g., programs, subroutines, logic and/or combinations of hardware and software components.

In one form, the generator <NUM> drive system <NUM> may comprise one or more embedded applications implemented as firmware, software, hardware, or any combination thereof. The generator <NUM> drive system <NUM> may comprise various executable modules such as software, programs, data, drivers, application program interfaces (APIs), and so forth. The firmware may be stored in nonvolatile memory (NVM), such as in bit-masked read-only memory (ROM) or flash memory. In various implementations, storing the firmware in ROM may preserve flash memory. The NVM may comprise other types of memory including, for example, programmable ROM (PROM), erasable programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), or battery backed random-access memory (RAM) such as dynamic RAM (DRAM), Double-Data-Rate DRAM (DDRAM), and/or synchronous DRAM (SDRAM).

In one form, the generator <NUM> drive system <NUM> comprises a hardware component implemented as a processor <NUM> for executing program instructions for monitoring various measurable characteristics of the ultrasonic surgical instrument <NUM> (<FIG>) and generating a step function output signal for driving the ultrasonic transducer in cutting and/or coagulation operating modes. It will be appreciated by those skilled in the art that the generator <NUM> and the drive system <NUM> may comprise additional or fewer components and only a simplified version of the generator <NUM> and the drive system <NUM> are described herein for conciseness and clarity. In various forms, as previously discussed, the hardware component may be implemented as a DSP, PLD, ASIC, circuits, and/or registers. In one form, the processor <NUM> may be configured to store and execute computer software program instructions to generate the step function output signals for driving various components of the ultrasonic surgical instrument <NUM>, such as a transducer, an end effector, and/or a blade.

In one form, under control of one or more software program routines, the processor <NUM> executes the methods in accordance with the described forms to generate a step function formed by a stepwise waveform of drive signals comprising current (I), voltage (V), and/or frequency (f) for various time intervals or periods (T). The stepwise waveforms of the drive signals may be generated by forming a piecewise linear combination of constant functions over a plurality of time intervals created by stepping the generator <NUM> drive signals, e.g., output drive current (I), voltage (V), and/or frequency (f). The time intervals or periods (T) may be predetermined (e.g., fixed and/or programmed by the user) or may be variable. Variable time intervals may be defined by setting the drive signal to a first value and maintaining the drive signal at that value until a change is detected in a monitored characteristic. Examples of monitored characteristics may comprise, for example, transducer impedance, tissue impedance, tissue heating, tissue transection, tissue coagulation, and the like. The ultrasonic drive signals generated by the generator <NUM> include, without limitation, ultrasonic drive signals capable of exciting the ultrasonic transducer <NUM> in various vibratory modes such as, for example, the primary longitudinal mode and harmonics thereof as well flexural and torsional vibratory modes.

In one form, the executable modules comprise one or more step function algorithm(s) <NUM> stored in memory that when executed causes the processor <NUM> to generate a step function formed by a stepwise waveform of drive signals comprising current (I), voltage (V), and/or frequency (f) for various time intervals or periods (T). The stepwise waveforms of the drive signals may be generated by forming a piecewise linear combination of constant functions over two or more time intervals created by stepping the generator's <NUM> output drive current (I), voltage (V), and/or frequency (f). The drive signals may be generated either for predetermined fixed time intervals or periods (T) of time or variable time intervals or periods of time in accordance with the one or more stepped output algorithm(s) <NUM>. Under control of the processor <NUM>, the generator <NUM> steps (e.g., increment or decrement) the current (I), voltage (V), and/or frequency (f) up or down at a particular resolution for a predetermined period (T) or until a predetermined condition is detected, such as a change in a monitored characteristic (e.g., transducer impedance, tissue impedance). The steps can change in programmed increments or decrements. If other steps are desired, the generator <NUM> can increase or decrease the step adaptively based on measured system characteristics.

In operation, the user can program the operation of the generator <NUM> using the input device <NUM> located on the front panel of the generator <NUM> console. The input device <NUM> may comprise any suitable device that generates signals <NUM> that can be applied to the processor <NUM> to control the operation of the generator <NUM>. In various forms, the input device <NUM> includes buttons, switches, thumbwheels, keyboard, keypad, touch screen monitor, pointing device, remote connection to a general purpose or dedicated computer. In other forms, the input device <NUM> may comprise a suitable user interface. Accordingly, by way of the input device <NUM>, the user can set or program the current (I), voltage (V), frequency (f), and/or period (T) for programming the step function output of the generator <NUM>. The processor <NUM> then displays the selected power level by sending a signal on line <NUM> to an output indicator <NUM>.

In various forms, the output indicator <NUM> may provide visual, audible, and/or tactile feedback to the surgeon to indicate the status of a surgical procedure, such as, for example, when tissue cutting and coagulating is complete based on a measured characteristic of the ultrasonic surgical instrument <NUM>, e.g., transducer impedance, tissue impedance, or other measurements as subsequently described. By way of example, and not limitation, visual feedback comprises any type of visual indication device including incandescent lamps or light emitting diodes (LEDs), graphical user interface, display, analog indicator, digital indicator, bar graph display, digital alphanumeric display. By way of example, and not limitation, audible feedback comprises any type of buzzer, computer generated tone, computerized speech, voice user interface (VUI) to interact with computers through a voice/speech platform. By way of example, and not limitation, tactile feedback comprises any type of vibratory feedback provided through an instrument housing handle assembly.

In one form, the processor <NUM> may be configured or programmed to generate a digital current signal <NUM> and a digital frequency signal <NUM>. These signals <NUM>, <NUM> are applied to a direct digital synthesizer (DDS) circuit <NUM> to adjust the amplitude and the frequency (f) of the current output signal <NUM> to the transducer. The output of the DDS circuit <NUM> is applied to an amplifier <NUM> whose output is applied to a transformer <NUM>. The output of the transformer <NUM> is the signal <NUM> applied to the ultrasonic transducer, which is coupled to a blade by way of a waveguide.

In one form, the generator <NUM> comprises one or more measurement modules or components that may be configured to monitor measurable characteristics of the ultrasonic instrument <NUM> (<FIG>). In the illustrated form, the processor <NUM> may be employed to monitor and calculate system characteristics. As shown, the processor <NUM> measures the impedance Z of the transducer by monitoring the current supplied to the transducer <NUM> and the voltage applied to the transducer. In one form, a current sense circuit <NUM> is employed to sense the current flowing through the transducer and a voltage sense circuit <NUM> is employed to sense the output voltage applied to the transducer. These signals may be applied to the analog-to-digital converter <NUM> (ADC) via an analog multiplexer <NUM> circuit or switching circuit arrangement. The analog multiplexer <NUM> routes the appropriate analog signal to the ADC <NUM> for conversion. In other forms, multiple ADCs <NUM> may be employed for each measured characteristic instead of the multiplexer <NUM> circuit. The processor <NUM> receives the digital output <NUM> of the ADC <NUM> and calculates the transducer impedance Z based on the measured values of current and voltage. The processor <NUM> adjusts the output drive signal <NUM> such that it can generate a desired power versus load curve. In accordance with programmed step function algorithms <NUM>, the processor <NUM> can step the drive signal <NUM>, e.g., the current or frequency, in any suitable increment or decrement in response to the transducer impedance Z.

Having described operational details of various forms of the surgical system <NUM>, operations for the above surgical system <NUM> may be further described in terms of a process for cutting and coagulating a blood vessel employing a surgical instrument comprising the input device <NUM> and the transducer impedance measurement capabilities described with reference to <FIG>. Although a particular process is described in connection with the operational details, it can be appreciated that the process merely provides an example of how the general functionality described herein can be implemented by the surgical system <NUM>. Further, the given process does not necessarily have to be executed in the order presented herein unless otherwise indicated.

In various forms, feedback is provided by the output indicator <NUM> shown in <FIG> and <FIG>. The output indicator <NUM> is particularly useful in applications where the tissue being manipulated by the end effector is out of the user's field of view and the user cannot see when a change of state occurs in the tissue. The output indicator <NUM> communicates to the user that a change in tissue state has occurred. As previously discussed, the output indicator <NUM> may be configured to provide various types of feedback to the user including, without limitation, visual, audible, and/or tactile feedback to indicate to the user (e.g., surgeon, clinician) that the tissue has undergone a change of state or condition of the tissue. By way of example, and not limitation, as previously discussed, visual feedback comprises any type of visual indication device including incandescent lamps or LEDs, graphical user interface, display, analog indicator, digital indicator, bar graph display, digital alphanumeric display. By way of example, and not limitation, audible feedback comprises any type of buzzer, computer generated tone, computerized speech, VUI to interact with computers through a voice/speech platform. By way of example, and not limitation, tactile feedback comprises any type of vibratory feedback provided through the instrument housing handle assembly. The change of state of the tissue may be determined based on transducer and tissue impedance measurements as previously described, or based on voltage, current, and frequency measurements.

In one form, the various executable modules (e.g., algorithms) comprising computer readable instructions can be executed by the processor <NUM> (<FIG>, <FIG>) portion of the generator <NUM>. In various forms, the operations described with respect to the algorithms may be implemented as one or more software components, e.g., programs, subroutines, logic; one or more hardware components, e.g., processors, DSPs, PLDs, ASICs, circuits, registers; and/or combinations of software and hardware. In one form, the executable instructions to perform the algorithms may be stored in memory. When executed, the instructions cause the processor <NUM> to determine a change in tissue state provide feedback to the user by way of the output indicator <NUM>. In accordance with such executable instructions, the processor <NUM> monitors and evaluates the voltage, current, and/or frequency signal samples available from the generator <NUM> and according to the evaluation of such signal samples determines whether a change in tissue state has occurred. As further described below, a change in tissue state may be determined based on the type of ultrasonic instrument and the power level that the instrument is energized at. In response to the feedback, the operational mode of the ultrasonic surgical instrument <NUM> may be controlled by the user or may be automatically or semi-automatically controlled.

The surgical instruments described herein can also include features to allow a user, such as a clinician, to select from a plurality of surgical modes based on the type of surgical procedure being performed and the type of tissue being treated by an end effector of a surgical instrument. Each surgical mode corresponds to an algorithm for controlling the power output from a generator, such as generator <NUM>, that is delivered to the end effector of the surgical instrument. As illustrated in <FIG>, a surgical instrument <NUM> can include a selector switch <NUM> that allows a clinician to select between various surgical modes.

Various algorithms can be used to allow for the selection of a plurality of surgical modes. In one form, a surgical mode can be based on the tissue being treated by the end effector. The surgical mode can also vary by the type of energy being delivered by the generator. In accordance with embodiments of the invention, it is possible for the generator to deliver energy that is adaptive based on changes to the tissue as the tissue is being treated by the end effector. In one form, the generator can monitor the temperature of the tissue and adjust the frequency of the output to regulate the temperature change in the tissue. In one form, the surgical instrument can include a switch for disabling the adaptive energy such that the user can control the delivery of adaptive energy from the generator regardless of the selected surgical mode. For example, one surgical mode can be selected for cutting avascular tissue and can include a high power output from the generator that is optimized for transection speed. Another surgical mode can be selected for coagulating tissue or vessels and can include low power output from the generator that is optimized for hemostasis of vessels. Another surgical mode can be selected for the treatment of solid organs and can include a lower power level output without adaptive energy from the generator that is optimized for the hemostasis of solid organs.

Although <FIG> illustrates a selector switch to control the selection of a surgical mode, various other techniques can be employed to allow a user to select a surgical mode. In one form, software on the surgical instrument can be used. For example, the surgical instruments can include a display such that the plurality of available surgical modes can be selected using the display. Similarly, in another form, the generator, such as generator <NUM>, can include software and a display such that the plurality of available surgical modes can be selected using the display on the generator. In another form, software can be included, either in the generator or the surgical instrument, to allow voice activation of a surgical mode. In another form, an external communication device can be used to communicate with either the generator or the surgical instrument to allow for the selection of a surgical mode. For example, any type of personal communication device can communicate with either the generator or the surgical instrument using a variety of techniques, including but not limited to short range radio, WiFi, or bluetooth technologies. The personal communication device can include software having the plurality of surgical modes such that a user can select one or more desired surgical modes using the personal communication device.

<FIG> illustrates a logic flow diagram <NUM> of one form of selecting a surgical mode corresponding to a tissue algorithm that may be implemented in one form of a generator. With reference now to the logic flow diagram <NUM> shown in <FIG> and the surgical system <NUM> of <FIG>, a user selects <NUM> a surgical mode that corresponding to an algorithm for controlling the generator <NUM> using a selector switch, such as the selector switch <NUM> of <FIG>. The selected algorithm is used to control <NUM> the power output from the generator <NUM>. The power output from the generator <NUM> is delivered <NUM> to the end effector of the surgical instrument such that the end effector can be used to treat tissue positioned within the end effector. A user determines <NUM> if an additional surgical mode is required to continue the surgical procedure being performed. If an additional surgical mode is not needed, the generator <NUM> can be deactivated <NUM>. If an additional surgical mode is required to continue the procedure, the user can select <NUM> another of the plurality of surgical modes to continue and complete the procedure. Any number of surgical modes can be selected in succession until the surgical procedure is completed.

Different clinicians often have different techniques for using ultrasonic surgical instruments and systems as described herein. In some forms, algorithms that can be customized and modified by a clinician can be employed. There are various aspects of the surgical mode algorithms that can be customized by a user. In one form, the power output from the generator and/or the timing of any drop in power can be selected. In one form, feedback from any component of the surgical system <NUM> can be selected, including the functionality of any monitors of audio feedback, such that the user can customize the feedback received during a surgical procedure.

The user also can communicate with the surgical system in a variety of ways to allow the use of the customized surgical modes. In one form, the generator can include a receptacle for receiving an input device having customized surgical modes thereon. For example, the input device can be in the form of an RFID swipe key, a USB device, or some form of digital passcode. The input device can also be in the form of a personal communication device that allows the user to create and modify customized surgical modes thereon and communicate, either wired and wirelessly with the generator. The input device can communicate the customized surgical modes to the generator such that, when a surgical mode is selected for use in a surgical procedure, the generator will deliver an output that corresponds to the setting customized for that particular user.

<FIG> illustrates a logic flow diagram <NUM> of one form of customizing a surgical mode corresponding to a tissue algorithm that may be implemented in one form of a generator. With reference now to the logic flow diagram <NUM> shown in <FIG> and the surgical system <NUM> of <FIG>, a user selects <NUM> a surgical mode for customization that corresponding to an algorithm for controlling the generator <NUM>. The selected algorithm is customized by selecting <NUM> a desired power output from the generator <NUM>. For example, a user can select <NUM> a minimum and/or maximum power output to be delivered by the generator during the use of that surgical mode. The selected algorithm is customized by selecting <NUM> a power drop and timing of the power drop for the power output from the generator during the use of that surgical mode. The customized algorithm is communicated <NUM> to the generator <NUM> using any of the techniques described herein. It will be appreciate that any aspect of the power output from the generator <NUM> can be customized and modified by a user to create a custom algorithm for use during a surgical procedure.

It can also be advantageous to employ techniques to lengthen the life of the energy pads on the end effectors. For example, the pad life can be improved by waiting for closure of the end effector around the tissue as both energy delivered to the pads without tissue compressed therebetween and friction can decreased the life and number of uses of the end effector pads. In various forms, this and other problems may be addressed by configuring a surgical instrument with a closure switch indicating when the end effector is fully closed with tissue therebetween. The generator may be configured to refrain from activating the surgical instrument until or unless the closure switch indicates that the clamp arm is fully closed. The closure switch can have various forms, including being positioned in a handle of a surgical device. The closure switch may be in electrical communication with the generator, such as generator <NUM>, for example. In one form, the generator is programmed not to activate the surgical instrument unless the switch indicates that the end effector is closed. For example, if the generator receives an activation request from one or more of the switches described herein, it may respond to the activation request only if the closure switch is activated to indicate that the end effector is closed. This allows the position of the end effector and the state of the closure switch to be used as an input to an algorithm for controlling the power output of the generator.

In another form, the generator is programmed not to activate any type of adaptive energy unless the switch indicates that the end effector is closed. In accordance with embodiments of the invention, if the generator receives an activation request from one or more of the switches described herein, it may respond to the activation request with adaptive energy only if the closure switch is activated to indicate that the end effector is closed. If the closure switch is not activated, indicating that the end effector is open, the generator can respond by delivering non-adaptive energy that can be used in certain surgical situations, such as back cutting or transecting a solid organ. If the closure switch is activated, indicating that the end effector is closed, the generator can respond by delivering adaptive energy that will be activated for the full activation cycle of the selected surgical mode, and can be used to most surgical situations such as any normal use of the end effector on tissue or vessels.

As illustrated in <FIG>, the surgical instrument can include a trigger that is used to move the end effector <NUM>. In one form, the trigger moves the end effector between a first position in which the end effector is opened and a second position in which the end effector is closed on a tissue for treatment. When the end effector is closed, the generator can deliver adaptive energy to the end effector to treat the tissue.

<FIG> illustrates a logic flow diagram <NUM> for selecting a surgical mode corresponding to a tissue algorithm using the position of an end effector of a surgical instrument as an algorithm input. With reference now to the logic flow diagram <NUM> shown in <FIG> and the surgical system <NUM> of <FIG>, a user selects <NUM> a surgical mode corresponding to an algorithm for controlling the generator <NUM>. The selected algorithm is used to control <NUM> the power output from the generator. Before the power is delivered to the end effector, the positon of the closure switch on the surgical instrument is checked <NUM>. For example, the positon of the trigger used to control the end effector is used an input to the algorithm. When the closure switch, or trigger, is in a first position such that switch and the end effector are open, the adaptive energy mode of the generator is disabled such that the adaptive energy cannot be delivered <NUM> to the end effector. When the closure switch, or trigger, is in a second position such that switch and the end effector are closed on the tissue to be treated, the adaptive energy mode of the generator is enabled such that the adaptive energy can be delivered <NUM> to the end effector.

In one form, it is possible to measure the position of the end effector to more precisely control the power output from the generator based on the position of the end effector relative to the tissue. In addition to the end effector being opened or closed around tissue, the end effector can also be partially closed around tissue. The angle of the partial closure of the end effector can be used to modify the power output from the generator rather that just activate or deactivate the adaptive energy delivered therefrom. <FIG> illustrates another form of a logic flow diagram <NUM> for selecting a surgical mode corresponding to a tissue algorithm using the position of an end effector of a surgical instrument as an algorithm input. With reference now to the logic flow diagram <NUM> shown in <FIG> and the surgical system <NUM> of <FIG>, a user selects <NUM> a surgical mode corresponding to an algorithm for controlling the generator <NUM>. The selected algorithm is used to control <NUM> the power output from the generator. Before the power is delivered to the end effector, the positon of the closure switch on the surgical instrument is checked <NUM>. For example, the positon of the trigger used to control the end effector is used an input to the algorithm. When the closure switch, or trigger, is in a first position such that switch and the end effector are open, the adaptive energy mode of the generator is disabled such that the adaptive energy cannot be delivered <NUM> to the end effector. When the closure switch, or trigger, is in a second position such that switch and the end effector are closed on the tissue to be treated, the adaptive energy mode of the generator is enabled such that the adaptive energy can be delivered <NUM> to the end effector. Measurement of the angle of closure of the end effector is used to adjust <NUM> the energy delivered from the generator <NUM>. In one form, the frequency slope of the energy can be varied depending on the angle of closure of the end effector. As the pressure on the tissue by the end effector increases and the angle of closure decreases, the power can be altered depending on the desired effect on tissue for the selected surgical mode. For example, the energy can be decreased to maintain constant cutting of the tissue as the angle of closure decreases.

The pad life of the end effectors can also be improved by taking in account the number of activation of the end effectors when the end effectors are closed on tissue. Thus, the adaptive energy delivered from the generator can be varied as a function of the number of closed activations of the end effectors. In one form, the adaptive energy can be delivered closer to the start of an activation cycle for a selected surgical mode as the number of closed activations of the end effectors increases. For example, a counter can be employed that tracks the number of closed activations of the end effectors and can be used as an input to the algorithm for controlling the energy delivered to the end effectors from the generator. Thus, the delivered adaptive energy can be varied based on the number of activations of the energy pads on the end effectors.

<FIG> illustrates another form of a logic flow diagram <NUM> for selecting a surgical mode corresponding to a tissue algorithm using the position of an end effector of a surgical instrument as an algorithm input. With reference now to the logic flow diagram <NUM> shown in <FIG> and the surgical system <NUM> of <FIG>, a user selects <NUM> a surgical mode corresponding to an algorithm for controlling the generator <NUM>. The selected algorithm is used to control <NUM> the power output from the generator. Before the power is delivered to the end effector, the positon of the closure switch on the surgical instrument is checked <NUM>. For example, the positon of the trigger used to control the end effector is used an input to the algorithm. When the closure switch, or trigger, is in a first position such that switch and the end effector are open, the adaptive energy mode of the generator is disabled such that the adaptive energy cannot be delivered <NUM> to the end effector. When the closure switch, or trigger, is in a second position such that switch and the end effector are closed on the tissue to be treated, a counter that measures the number of closed activations of the end effectors is increased <NUM>. It is possible to compare <NUM> the counter to a threshold, for example, that could inform a user that the energy pads on the end effectors should be replaced as there have been a large number of closed activations. The adaptive energy mode of the generator is enabled such that the adaptive energy can be delivered <NUM> to the end effector. The adaptive energy delivered will be affected by the counter as the counter will be used as an input for the algorithm that controls the energy delivered by the generator.

As explained above, there are a plurality of surgical modes that can be utilized for controlling the output from the generator. The following table, Table <NUM>, illustrates exemplary surgical modes and algorithms for controlling the power output from the generator.

While various details have been set forth in the foregoing description, it will be appreciated that the various aspects of the serial communication protocol for medical device may be practiced without these specific details. For example, for conciseness and clarity selected aspects have been shown in block diagram form rather than in detail. Some portions of the detailed descriptions provided herein may be presented in terms of instructions that operate on data that is stored in a computer memory. Such descriptions and representations are used by those skilled in the art to describe and convey the substance of their work to others skilled in the art. In general, an algorithm refers to a self-consistent sequence of steps leading to a desired result, where a "step" refers to a manipulation of physical quantities which may, though need not necessarily, take the form of electrical or magnetic signals capable of being stored, transferred, combined, compared, and otherwise manipulated. It is common usage to refer to these signals as bits, values, elements, symbols, characters, terms, numbers, or the like. These and similar terms may be associated with the appropriate physical quantities and are merely convenient labels applied to these quantities.

Unless specifically stated otherwise as apparent from the foregoing discussion, it is appreciated that, throughout the foregoing description, discussions using terms such as "processing" or "computing" or "calculating" or "determining" or "displaying" or the like, refer to the action and processes of a computer system, or similar electronic computing device, that manipulates and transforms data represented as physical (electronic) quantities within the computer system's registers and memories into other data similarly represented as physical quantities within the computer system memories or registers or other such information storage, transmission or display devices.

It is worthy to note that any reference to "one aspect," "an aspect," "one form," or "an form" means that a particular feature, structure, or characteristic described in connection with the aspect is included in at least one aspect. Thus, appearances of the phrases "in one aspect," "in an aspect," "in one form," or "in an form" in various places throughout the specification are not necessarily all referring to the same aspect. Furthermore, the particular features, structures or characteristics may be combined in any suitable manner in one or more aspects.

Some aspects may be described using the expression "coupled" and "connected" along with their derivatives. For example, some aspects may be described using the term "connected" to indicate that two or more elements are in direct physical or electrical contact with each other. In another example, some aspects may be described using the term "coupled" to indicate that two or more elements are in direct physical or electrical contact. The term "coupled," however, also may mean that two or more elements are not in direct contact with each other, but yet still co-operate or interact with each other.

Although various forms have been described herein, many modifications, variations, substitutions, changes, and equivalents to those forms may be implemented and will occur to those skilled in the art. Also, where materials are disclosed for certain components, other materials may be used. It is therefore to be understood that the foregoing description and the appended claims are intended to cover all such modifications and variations as falling within the scope of the appended claims.

In a general sense, those skilled in the art will recognize that the various aspects described herein which can be implemented, individually and/or collectively, by a wide range of hardware, software, firmware, or any combination thereof can be viewed as being composed of various types of "electrical circuitry. " Consequently, as used herein "electrical circuitry" includes, but is not limited to, electrical circuitry having at least one discrete electrical circuit, electrical circuitry having at least one integrated circuit, electrical circuitry having at least one application specific integrated circuit, electrical circuitry forming a general purpose computing device configured by a computer program (e.g., a general purpose computer configured by a computer program which at least partially carries out processes and/or devices described herein, or a microprocessor configured by a computer program which at least partially carries out processes and/or devices described herein), electrical circuitry forming a memory device (e.g., forms of random access memory), and/or electrical circuitry forming a communications device (e.g., a modem, communications switch, or optical-electrical equipment). Those having skill in the art will recognize that the subject matter described herein may be implemented in an analog or digital fashion or some combination thereof.

The foregoing detailed description has set forth various forms of the devices and/or processes via the use of block diagrams, flowcharts, and/or examples. Insofar as such block diagrams, flowcharts, and/or examples contain one or more functions and/or operations, it will be understood by those within the art that each function and/or operation within such block diagrams, flowcharts, or examples can be implemented, individually and/or collectively, by a wide range of hardware, software, firmware, or virtually any combination thereof. In one form, several portions of the subject matter described herein may be implemented via Application Specific Integrated Circuits (ASICs), Field Programmable Gate Arrays (FPGAs), digital signal processors (DSPs), or other integrated formats. However, those skilled in the art will recognize that some aspects of the forms disclosed herein, in whole or in part, can be equivalently implemented in integrated circuits, as one or more computer programs running on one or more computers (e.g., as one or more programs running on one or more computer systems), as one or more programs running on one or more processors (e.g., as one or more programs running on one or more microprocessors), as firmware, or as virtually any combination thereof, and that designing the circuitry and/or writing the code for the software and or firmware would be well within the skill of one of skill in the art in light of this disclosure. In addition, those skilled in the art will appreciate that the mechanisms of the subject matter described herein are capable of being distributed as a program product in a variety of forms, and that an illustrative form of the subject matter described herein applies regardless of the particular type of signal bearing medium used to actually carry out the distribution. Examples of a signal bearing medium include, but are not limited to, the following: a recordable type medium such as a floppy disk, a hard disk drive, a Compact Disc (CD), a Digital Video Disk (DVD), a digital tape, a computer memory, etc.; and a transmission type medium such as a digital and/or an analog communication medium (e.g., a fiber optic cable, a waveguide, a wired communications link, a wireless communication link (e.g., transmitter, receiver, transmission logic, reception logic, etc.), etc.).

One skilled in the art will recognize that the herein described components (e.g., operations), devices, objects, and the discussion accompanying them are used as examples for the sake of conceptual clarity and that various configuration modifications are contemplated. Consequently, as used herein, the specific exemplars set forth and the accompanying discussion are intended to be representative of their more general classes. In general, use of any specific exemplar is intended to be representative of its class, and the non-inclusion of specific components (e.g., operations), devices, and objects should not be taken limiting.

The various singular/plural permutations are not expressly set forth herein for sake of clarity.

The herein described subject matter sometimes illustrates different components contained within, or connected with, different other components. It is to be understood that such depicted architectures are merely exemplary, and that in fact many other architectures may be implemented which achieve the same functionality. Likewise, any two components so associated can also be viewed as being "operably connected," or "operably coupled," to each other to achieve the desired functionality, and any two components capable of being so associated can also be viewed as being "operably couplable," to each other to achieve the desired functionality. Specific examples of operably couplable include but are not limited to physically mateable and/or physically interacting components, and/or wirelessly interactable, and/or wirelessly interacting components, and/or logically interacting, and/or logically interactable components.

In some instances, one or more components may be referred to herein as "configured to," "configurable to," "operable/operative to," "adapted/adaptable," "able to," "conformable/conformed to," etc. Those skilled in the art will recognize that "configured to" can generally encompass active-state components and/or inactive-state components and/or standby-state components, unless context requires otherwise.

Although various operational flows are presented in a sequence(s), it should be understood that the various operations may be performed in other orders than those which are illustrated, or may be performed concurrently. Examples of such alternate orderings may include overlapping, interleaved, interrupted, reordered, incremental, preparatory, supplemental, simultaneous, reverse, or other variant orderings, unless context dictates otherwise. Furthermore, terms like "responsive to," "related to," or other past-tense adjectives are generally not intended to exclude such variants, unless context dictates otherwise.

In certain cases, use of a system or method may occur in a territory even if components are located outside the territory. For example, in a distributed computing context, use of a distributed computing system may occur in a territory even though parts of the system may be located outside of the territory (e.g., relay, server, processor, signal-bearing medium, transmitting computer, receiving computer, etc. located outside the territory).

A sale of a system or method may likewise occur in a territory even if components of the system or method are located and/or used outside the territory. Further, implementation of at least part of a system for performing a method in one territory does not preclude use of the system in another territory.

Claim 1:
An apparatus for dissection and coagulation of tissue, comprising:
a surgical instrument having an end effector (<NUM>) configured to dissect and seal tissue at a distal end thereof;
an activator switch (<NUM>);
a generator (<NUM>) electrically coupled to the activator switch and the surgical instrument, the generator configured to deliver energy to the end effector when the generator receives an activation request from the activation switch;
a surgical mode selector input (<NUM>) having a plurality of surgical modes for selection by a user such that each surgical mode corresponds to an algorithm for controlling the power output from the generator; and
a closure switch configured to move between a first position in which the end effector is opened to allow tissue to be positioned within the end effector and a second position in which the end effector is closed such that tissue to held by the end effector, wherein:
an adaptive energy mode of the generator is enabled such that the generator is configured to deliver adaptive energy, which is adaptive based on changes to the tissue as the tissue is being treated by the end effector, to the end effector when the generator receives the activation request only if the closure switch is in the second position and the end effector is closed on the tissue, and the generator is configured to deliver non-adaptive energy to the end effector when the generator receives the activation request and the closure switch is in the first position.