Arc based adaptive control system for an electrosurgical unit

• US 7,651,492 B2
• Filed: 04/24/2006
• Issued: 01/26/2010
• Est. Priority Date: 04/24/2006
• Status: Active Grant

• Current Assignee: Covidien AG (Medtronic Plc)
• Original Assignee: Covidien AG (Medtronic Plc)
• Inventors: Wham, Robert H.
• Primary Examiner(s): Peffley; Michael
• Assistant Examiner(s): HUPCZEY, JR, RONALD JAMES
• Application Number:
  US11/409,574
• Publication Number:
  US 20070250052A1
• Time in Patent Office: 1,373 Days
• Field of Search: 606 32- 52
• US Class Current: 606/34
• CPC Class Codes: A61B 18/1206 Generators therefor
• CPC Class Codes: A61B 2018/00726 Duty cycle
• CPC Class Codes: A61B 2018/00875 Resistance or impedance
• CPC Class Codes: A61B 2018/1213 creating an arc

Abstract

A system and method for performing electrosurgical procedures are disclosed. The system includes an electrosurgical generator adapted to supply electrosurgical energy to tissue in form of one or more electrosurgical waveforms having a crest factor and a duty cycle. The system also includes sensor circuitry adapted to measure impedance and to obtain one or more measured impedance signals. The sensor circuitry is further adapted to generate one or more arc detection signals upon detecting an arcing condition§. The system further includes a controller adapted to generate one or more target control signals as a function of the measured impedance signals and to adjust output of the electrosurgical generator based on the arc detection signal. An electrosurgical instrument is also included having one or more active electrodes adapted to apply electrosurgical energy to tissue.

Claims

1. An electrosurgical system comprising:

an electrosurgical generator adapted to supply electrosurgical energy to tissue in the form of at least one electrosurgical waveform having a crest factor and a duty cycle;

sensor circuitry adapted to measure impedance and to obtain at least one measured impedance signal, the sensor circuitry further adapted to generate at least one arc detection signal upon detection of an arcing condition;

a high pass filter adapted to filter the at least one measured impedance signal to obtain an absolute value thereof;

a low pass filter adapted to filter the absolute value of the at least one measured impedance signal to obtain the at least one arc detection signal;

a controller adapted to generate at least one target control signal as a function of the at least one measured impedance signal and to adjust output of the electrosurgical generator based on the at least one arc detection signal; and

an electrosurgical instrument including at least one active electrode adapted to apply electrosurgical energy to tissue.

2. An electrosurgical system as in claim 1, wherein the at least one arc detection signal is scaled to represent the level of arcing.

3. An electrosurgical system as in claim 1, wherein the controller adjusts the output of the electrosurgical generator by generating at least one target control signal as a function of an average impedance value.

4. An electrosurgical system as in claim 1, wherein the controller adjusts output of the electrosurgical generator by adjusting at least one of the crest factor and the duty cycle of the at least one waveform.

5. A method for performing an electrosurgical procedure comprising the steps of:

supplying electrosurgical energy from an electrosurgical generator to tissue in the form of at least one electrosurgical waveform having a crest factor and a duty cycle;

measuring impedance to obtain at least one measured impedance signal;

generating at least one arc detection signal upon detecting an arcing conditions;

filtering the at least one measured impedance signal through a high pass filter to obtain an absolute value thereof;

filtering the absolute value of the at least one measured impedance signal through a low pass filter to obtain the at least one arc detection signal;

generating at least one target control signal as a function of the at least one measured impedance signal; and

adjusting output of the electrosurgical generator based on the at least one arc detection signal.

6. A method as in claim 5, further comprising the step of:

scaling the at least one arc detection signal according to a scale representing level of arcing.

7. A method as in claim 5, wherein the step of adjusting output of the electrosurgical generator further comprises:

adjusting the output of the electrosurgical generator by generating at least one target control signal as a function of an average impedance value.

8. A method as in claim 5, wherein the step of adjusting output of the electrosurgical generator further comprises:

adjusting at least one of the crest factor and the duty cycle of the at least one waveform.

9. An electrosurgical generator:

an RF output stage adapted to supply electrosurgical energy to tissue in the form of at least one electrosurgical waveform having a crest factor and a duty cycle;

sensor circuitry adapted to measure impedance and to obtain at least one measured impedance signal, the sensor circuitry further adapted to generate at least one arc detection signal upon detecting an arcing condition;

a high pass filter adapted to filter the at least one measured impedance signal to obtain an absolute value thereof;

a low pass filter adapted to filter the absolute value of the at least one measured impedance signal to obtain the at least one arc detection signal; and

a controller adapted to generate at least one target control signal as a function of the at least one measured impedance signal and to adjust output of the electrosurgical generator based on the at least one arc detection signal.

10. An electrosurgical generator as in claim 9, wherein the at least one arc detection signal is scaled according to represent the level of arcing.

11. An electrosurgical generator as in claim 9, wherein the controller adjusts the output of the electrosurgical generator by generating at least one target control signal as a function of an average impedance value.

12. An electrosurgical generator as in claim 9, wherein the controller adjusts output of the electrosurgical generator by adjusting at least one of the crest factor and the duty cycle of the at least one waveform.