Electrosurgical method using laterally arranged active electrode

• US 6,960,204 B2
• Filed: 07/16/2003
• Issued: 11/01/2005
• Est. Priority Date: 05/10/1993
• Status: Expired due to Fees

• Current Assignee: ArthroCare Corporation (Smith & Nephew PLC)
• Original Assignee: ArthroCare Corporation (Smith & Nephew PLC)
• Inventors: Thapliyal, Hira V, Eggers, Philip E.
• Primary Examiner(s): Cohen, Lee S.
• Application Number:
  US10/621,839
• Publication Number:
  US 20040087939A1
• Time in Patent Office: 839 Days
• Field of Search: 606/32, 606/41, 606/45, 606/46, 606 48- 50, 604/35, 604/114, 607/99, 607/105, 607/11.3
• US Class Current: 606/32
• 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 probe comprises a shaft having an electrode array (12) at its distal end and a connector at its proximal end. The array (12) includes a plurality of isolated electrode terminals, and an electrosurgical power supply (28) is provided with a multiplicity of independently limited or controlled current sources and a connector. The electrosurgical probe and the power supply may be connected through their respective connectors so that the independent current sources are connected to individual electric terminals. By applying very high frequency electrical energy to the electrode array, target tissue may be cut or ablated while heat dissipation through low impedance paths, such as blood and normal saline, will be minimized.

Claims

1. A method for applying electrical energy to a body structure at a target site on or within a patient'"'"'s body, the method comprising:

positioning an active electrode into at least close proximity with a body structure at the target site;

spacing a return electrode from the active electrode such that the return electrode does not contact the body structure; and

applying a high frequency voltage difference between the active and return electrodes such that an electrical current flows from the active electrode, through the target site, and to the return electrode, the high frequency voltage difference being sufficient to remove at least a portion of the body structure at the target site wherein said active electrode is arranged on a lateral surface of a shaft such that the active electrode may be traversed across the body structure upon longitudinal movement of the shaft.

2. The method of claim 1 wherein the return electrode is spaced a distance of about 0.5 to 25 mm from the tissue structure during the applying step.

3. The method of claim 1 wherein the return electrode is spaced a distance of about 1.0 to 5.0mm from the tissue structure during the applying step.

4. The method of claim 1 further comprising introducing an electrically conductive fluid to the target site such that the active and return electrodes contact the electrically conductive fluid and the electrically conductive fluid completes a conductive path between the active and return electrodes.

5. The method of claim 4 wherein electric current flows substantially through the electrically conductive fluid while minimizing electric current flow passing through the body structure.

6. The method of claim 4 wherein at least a portion of an electric current passes through the body structure.

7. The method of claim 4 further comprising immersing the target site within a volume of the electrically conductive fluid and positioning the return electrode within the volume of electrically conductive fluid to generate a current flow path between the active and return electrodes.

8. The method of claim 4 wherein the active electrode is introduced into a cavity in the patient'"'"'s body flooded with the electrically conductive fluid.

9. The method of claim 4 wherein the electrically conductive fluid comprises isotonic saline.

10. The method of claim 1 wherein the active electrode includes an array of electrically isolated active electrodes disposed near the distal end of an instrument shaft.

11. The method of claim 10 including independently controlling current flow from at least two of the active electrodes based on electrical impedance between each active electrode and the return electrode.

12. The method of claim 1 further comprising wherein the return electrode is spaced from the active electrode by an electrically insulating member comprising an inorganic material.

13. The method of claim 12 wherein the inorganic material is selected from the group consisting essentially of ceramic, glass and glass/ceramic compositions.

14. The method of claim 1 wherein the frequency of the applied voltage is about 50 kHz to about 400 MHz.

15. The method of claim 1 wherein the high frequency voltage is greater than 10 volts and less than 500 volts.

16. The method of claim 1 wherein the active electrode and the return electrode are configured to effect the electrical breakdown of tissue in the immediate vicinity of the active electrode when high frequency voltage is applied between the active electrode and the return electrode in the presence of electrically conducting fluid.

17. The method of claim 1 further comprising generating a high electric field intensity at a distal portion of the active electrode.

18. The method of claim 1 wherein the power applied to the active electrode is controlled based on the electrical impedance between the active electrode and the return electrode.

19. The method of claim 18 further comprising limiting power to the active electrode when the electrical impedance is less than a threshold value.

20. The method of claim 1 wherein temperature at the target site is measured by a temperature sensor adjacent to the active electrode and power delivery to the active electrode is limited if the measured temperature exceeds a threshold value.

21. The method of claim 1 wherein the return electrode has a substantially greater exposed surface area than the active electrode.

22. The method of claim 1 wherein the return electrode has an exposed surface area at least 5 times greater than an exposed surface area of the active electrode.

23. The method of claim 1 wherein the return electrode is arranged circumferentially on said shaft.