Instrument for electrosurgical tissue treatment

• US 20040054366A1
• Filed: 09/12/2003
• Published: 03/18/2004
• Est. Priority Date: 08/11/1998
• Status: Active Grant

• Current Assignee: ArthroCare Corporation (Smith & Nephew PLC)
• Original Assignee: ArthroCare Corporation (Smith & Nephew PLC)
• Inventors: Woloszko, Jean, Davison, Paul O., Jenkins, Tom
• Granted Patent: US 7,276,063 B2
• Time in Patent Office: Days
• US Class Current: 606/39
• CPC Class Codes: A61B 18/14 Probes or electrodes therefor
• 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 2018/048 in gaseous form
• CPC Class Codes: A61B 2018/122 ionizing, with corona
• CPC Class Codes: A61B 2218/002 Irrigation

Abstract

Systems and methods are provided for applying a high frequency voltage in the presence of an electrically conductive fluid to create a relatively low-temperature plasma for ablation of tissue adjacent to, or in contact with, the plasma. In one embodiment, an electrosurgical probe or catheter is positioned adjacent the target site so that one or more active electrode(s) are brought into contact with, or close proximity to, a target tissue in the presence of electrically conductive fluid. High frequency voltage is then applied between the active electrode(s) and one or more return electrode(s) to non-thermally generate a plasma adjacent to the active electrode(s), and to volumetrically remove or ablate at least a portion of the target tissue. The high frequency voltage generates electric fields around the active electrode(s) with sufficient energy to ionize the conductive fluid adjacent to the active electrode(s). Within the ionized gas or plasma, free electrons are accelerated, and electron-atoms collisions liberate more electrons, and the process cascades until the plasma contains sufficient energy to break apart the tissue molecules, causing molecular dissociation and ablation of the target tissue.

Claims

1. An electrosurgical instrument for applying electrical energy to tissue at a target site, the instrument comprising:

a tissue-contacting surface; and

at least one active electrode recessed within the tissue-contacting surface and having a curved configuration.

2. The instrument of claim 1 further comprising:

a return electrode spaced apart from the at least one active electrode.

3. The instrument of claim 2 further comprising:

a fluid source for providing electrically conductive fluid between the return electrode and the at least one active electrode; and

one or more connectors coupled to the at least one active electrode for connecting the active electrodes to a high frequency power supply.

4. The instrument of claim 1 further comprising:

at least one opening within the tissue-contacting surface for venting the target site.

5. The instrument of claim 4 wherein the at least one opening is concentric with the at least one active electrode.

6. The instrument of claim 1 further comprising:

at least one recess within the tissue-contacting surface for facilitating fluid flow to the at least one active electrode.

7. The instrument of claim 1 wherein the at least one active electrode is positioned within a cavity within the tissue-contacting surface.

8. The instrument of claim 1 wherein the at least one active electrode is flush with the tissue-contacting surface.

9. The instrument of claim 1 wherein the at least one active electrode is recessed below the tissue-contacting surface.

10. The instrument of claim 2 wherein the return electrode is positioned about the tissue-contacting surface.

11. The instrument of claim 1 wherein the at least one active electrode has an annular configuration.

12. An electrosurgical instrument for applying electrical energy to tissue at a target site, the instrument comprising:

a shaft, a proximal end and a distal end;

a tissue treatment member at the distal end, the tissue treatment member having an annular configuration and comprising;

a tissue-contacting surface;

an outer surface; and

an active electrode having an annular configuration and recessed within the tissue-contacting surface.

13. The instrument of claim 12 further comprising:

a return electrode having an annular configuration and positioned about the outer surface.

14. The instrument of claim 13 further comprising:

a fluid source for providing electrically conductive fluid between the return electrode and the at least one active electrode; and

one or more connectors coupled to the at least one active electrode for connecting the active electrodes to a high frequency power supply.

15. The instrument of claim 12 wherein the annular configuration of the tissue treatment member defines an opening for venting the target site.

16. The instrument of claim 12 wherein the tissue treatment member further comprises at least one recess therein for facilitating fluid flow to the at least one active electrode.

17. The instrument of claim 12 wherein the at least one active electrode is flush with the tissue-contacting surface.

18. The instrument of claim 12 wherein the at least one active electrode is recessed below the tissue-contacting surface.

19. The instrument of claim 13 wherein the outer surface extends beyond return electrode to define an active portion of the tissue treatment member adjacent the active electrode.

20. An electrosurgical instrument for applying electrical energy to tissue at a target site, the instrument comprising:

a shaft, a proximal end and a distal end;

a non-electrically conducting support disposed at the distal end, said support having an annular configuration and a tissue-contacting surface having an annular recess therein;

an active electrode positioned within the annular recess; and

a return electrode positioned about an outer surface of said support

21. The instrument of claim 20 wherein said support comprises ceramic.

22. The instrument of claim 21 wherein said return electrode has a clip shape.

23. The instrument of claim 22 having only one active electrode.