Methods and apparatus for surgical cutting

• US 5,766,153 A
• Filed: 12/05/1996
• Issued: 06/16/1998
• Est. Priority Date: 05/10/1993
• Status: Expired due to Term

• Current Assignee: ArthroCare Corporation (Smith & Nephew PLC)
• Original Assignee: ArthroCare Corporation (Smith & Nephew PLC)
• Inventors: Eggers, Philip E., Thapliyal, Hira V.
• Primary Examiner(s): Buiz, Michael
• Assistant Examiner(s): Mendez, Manuel
• Application Number:
  US08/760,768
• Time in Patent Office: 558 Days
• Field of Search: 604/22, 604/49, 604/114, 606/27-29, 606/32-35, 606/37, 606/39, 606/40-41, 606/45, 606/47, 606/48-50
• US Class Current: 604/114
• CPC Class Codes: A61B 18/12 by passing a current through the tissue to be heated, e.g. high-frequency current
• CPC Class Codes: A61B 18/1206 Generators therefor
• CPC Class Codes: A61B 18/1402 Probes for open surgery
• CPC Class Codes: A61B 18/148 having a short, rigid shaft for accessing the inner body transcutaneously, e.g. for neurosurgery or arthroscopy
• CPC Class Codes: A61B 18/1482 having a long rigid shaft for accessing the inner body transcutaneously in minimal invasive surgery, e.g. laparoscopy
• CPC Class Codes: A61B 18/1485 having a short rigid shaft for accessing the inner body through natural openings
• CPC Class Codes: A61B 18/149 bow shaped or with rotatable body at cantilever end, e.g. for resectoscopes, or coagulating rollers
• CPC Class Codes: A61B 18/1492 having a flexible, catheter-like structure, e.g. for heart ablation A61B18/1477 takes precedence
• CPC Class Codes: A61B 2017/00026 Conductivity or impedance, e.g. of tissue
• CPC Class Codes: A61B 2017/00084 Temperature
• CPC Class Codes: A61B 2017/00097 one of the thermometric elements being an electrode or the heating element
• CPC Class Codes: A61B 2017/00101 using an array of thermosensors
• CPC Class Codes: A61B 2017/00247 Making holes in the wall of the heart, e.g. laser Myocardial revascularization
• CPC Class Codes: A61B 2017/00292 mounted on or guided by flexible, e.g. catheter-like, means
• CPC Class Codes: A61B 2017/003 Steerable
• CPC Class Codes: A61B 2017/22001 Angioplasty, e.g. PCTA
• CPC Class Codes: A61B 2017/22038 with a guide wire
• CPC Class Codes: A61B 2018/00029 open
• CPC Class Codes: A61B 2018/0016 Energy applicators arranged in a two- or three dimensional array
• CPC Class Codes: A61B 2018/00178 Electrical connectors
• CPC Class Codes: A61B 2018/00196 : reciprocating lengthwise
• CPC Class Codes: A61B 2018/00392 : Transmyocardial revascularisation
• CPC Class Codes: A61B 2018/00577 : Ablation
• CPC Class Codes: A61B 2018/00583 : Coblation, i.e. ablation using a cold plasma
• CPC Class Codes: A61B 2018/00601 : Cutting
• CPC Class Codes: A61B 2018/00642 : with feedback, i.e. closed loop control
• CPC Class Codes: A61B 2018/0066 : without feedback, i.e. open loop control
• CPC Class Codes: A61B 2018/00678 : upper
• CPC Class Codes: A61B 2018/00726 : Duty cycle
• CPC Class Codes: A61B 2018/00761 : Duration
• CPC Class Codes: A61B 2018/00791 : Temperature
• CPC Class Codes: A61B 2018/00797 : measured by multiple temperature sensors
• CPC Class Codes: A61B 2018/00821 : measured by a thermocouple
• CPC Class Codes: A61B 2018/00827 : Current
• CPC Class Codes: A61B 2018/00875 : Resistance or impedance
• CPC Class Codes: A61B 2018/00886 : Duration
• CPC Class Codes: A61B 2018/1213 : creating an arc
• CPC Class Codes: A61B 2018/124 : switching the output to different electrodes, e.g. sequentially
• CPC Class Codes: A61B 2018/126 : bipolar
• CPC Class Codes: A61B 2018/1273 : including multiple generators in one device
• CPC Class Codes: A61B 2018/1407 : Loop
• CPC Class Codes: A61B 2018/1467 : using more than two electrodes on a single probe
• CPC Class Codes: A61B 2018/1472 : for use with liquid electrolyte, e.g. virtual electrodes
• CPC Class Codes: A61B 2018/162 : located on the probe body
• CPC Class Codes: A61B 2090/378 : using ultrasound
• CPC Class Codes: A61B 2218/002 : Irrigation
• CPC Class Codes: A61B 2218/007 : Aspiration
• CPC Class Codes: A61F 2/2493 : Transmyocardial revascularisation [TMR] devices
• CPC Class Codes: A61M 25/0133 : Tip steering devices
• CPC Class Codes: A61M 25/0147 : with movable mechanical means, e.g. pull wires
• CPC Class Codes: A61M 25/0158 : with magnetic or electrical means, e.g. by using piezo materials, electroactive polymers, magnetic materials or by heating of shape memory materials
• CPC Class Codes: A61N 1/05 : for implantation or insertion into the body, e.g. heart electrode A61N1/06 takes precedence
• CPC Class Codes: A61N 1/403 : for thermotherapy, e.g. hyperthermia

Abstract

An electrosurgical system for applying electrical energy to a tissue structure within a patient'"'"'s body comprises an electrosurgical probe and one or more high frequency power supplies. The probe comprises a shaft having an electrode array of isolated electrode terminals at its distal end. The terminals are each coupled to one of a multiplicity of current limiting elements, such as inductors. The inductors, together with the inherent capacitance of the load, form a series resonant output circuit having a resonant frequency greater than the operating frequency of the power supply.

Claims

1. An electrosurgical apparatus comprising:

an electrosurgical power supply;

an electrical load coupled to the generator including one or more electrodes, the electrical load being inherently capacitive; and

a conductor electrically coupling the electrical load to the generator, wherein the power supply includes at least one current limiting element in series with the conductor, the capacitance of the electrical load and the current limiting element together forming a series resonant output circuit.

2. The apparatus of claim 1 wherein the current limiting element comprises an inductor.

3. The apparatus of claim 2 wherein inductor has an inductance of about 200 to 2500 microhenries.

4. The apparatus of claim 1 wherein the series resonant output circuit has a resonant frequency higher than the operating frequency of the power supply.

5. The apparatus of claim 1 further comprising at least one capacitor in series with the inductor to form a lumped capacitance coupled across the power supply output.

6. The apparatus of claim 1 wherein the electrical load comprises a bipolar unit including a pair of electrodes each connected to a respective output terminal of the power supply.

7. The apparatus of claim 1 wherein the electrical load comprises a bipolar unit including a common electrode and a plurality of active electrode terminals each connected to a respective output terminal of the power supply.

8. The apparatus of claim 4 wherein the operating frequency of the power supply is about 50 kHz to about 400 kHz.

9. An electrosurgical apparatus comprising:

a power supply having an output stage with one or more independent current-limited current sources;

one or more conductors adapted for coupling to one or more electrodes; and

one or more output terminals for independently coupling each of the conductors to one of the current-limited current sources, the output terminals being coupled in series between the current-limited current sources and the conductors.

10. The apparatus of claim 9 wherein the output stage includes a parallel resonant output circuit, the conductors being connected in series between the resonant output circuit and the associated output terminals.

11. The apparatus of claim 9 wherein the current limiting element comprises an inductor for forming a series resonant circuit with electrodes, the series resonant circuit having a capacitance.

12. The apparatus of claim 11 wherein the inductor has an inductance of about 200 to 2500 microhenries.

13. The apparatus of claim 9 wherein the parallel resonant output circuit has a resonant frequency higher than the operating frequency of the power supply.

14. The apparatus of claim 11 further comprising at least one capacitor in series with the inductor to form a lumped capacitance coupled across the power supply output.

15. The apparatus of claim 9 wherein the operating frequency of the power supply is about 50 kHz to about 400 kHz.

16. An electrosurgical apparatus comprising:

an instrument handle having one or more power supply conductors for delivering radio frequency power from an electrosurgical power supply;

an electrode unit mounted on a distal end portion of the instrument handle, the electrode unit comprising one or more electrodes each independently coupled to one of the power supply conductors; and

a current limiting element connected across the power supply conductors to supplement the inherent capacitance of the electrode unit and the power supply conductors.

17. The apparatus of claim 16 wherein the capacitance of the electrical load and the current limiting element together form a series resonant output circuit.

18. The apparatus of claim 16 wherein the current limiting element comprises a capacitor.

19. The apparatus of claim 16 wherein the current limiting element comprises one or more inductors coupled in series between the power supply conductors and the power supply.

20. The apparatus of claim 16 wherein the instrument handle further comprises a shaft having a proximal end and a distal end, and the electrode unit comprises an electrode array disposed near the distal end of the shaft, said array including a plurality of electrically isolated electrode terminals disposed over a contact surface.

21. The apparatus of claim 20 further comprising a common electrode on the shaft, wherein one of the power supply conductors electrically couples the common electrode to the power supply.

22. the apparatus of claim 20 further comprising a temperature sensor located in the electrode array.