Internally located return electrode electrosurgical apparatus, system and method

• US 20070208334A1
• Filed: 03/02/2006
• Published: 09/06/2007
• Est. Priority Date: 03/02/2006
• Status: Active Grant

• Current Assignee: ArthroCare Corporation (Smith & Nephew PLC)
• Original Assignee: ArthroCare Corporation (Smith & Nephew PLC)
• Inventors: Woloszko, Jean, Jenkins, Thomas
• Granted Patent: US 7,879,034 B2
• Time in Patent Office: Days
• US Class Current: 606/41
• 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 2018/00053 Mechanical features of the instrument of device
• CPC Class Codes: A61B 2018/0044 Spinal cord
• CPC Class Codes: A61B 2018/00583 Coblation, i.e. ablation using a cold plasma
• CPC Class Codes: A61B 2018/1472 for use with liquid electrolyte, e.g. virtual electrodes
• CPC Class Codes: A61B 2218/002 Irrigation
• CPC Class Codes: A61B 2218/007 Aspiration
• CPC Class Codes: A61B 2218/008 for smoke evacuation

Abstract

A bipolar, plasma-generating electrosurgical apparatus and system wherein the return electrode is enclosed within an electrosurgical shaft, and the active electrode is located on the outside surface of the shaft such that in treating the tissue, the tissue is exposed to plasma generated on the active electrode, but is minimally exposed to electric fields generated between the active and return electrodes. Due to the configuration of the electrodes, electric fields generated between the electrodes are directed away from the target tissue and inwardly towards the return electrode within the shaft, thereby electrical stimulation of neuromuscular structures in the tissue by the electric fields is minimized.

Claims

1. An electrosurgical apparatus comprising:

a shaft having a proximal end portion and a distal end portion;

an active electrode disposed on the surface of the distal end portion of the shaft;

a return electrode disposed within the distal end portion of the shaft;

an insulating member positioned on the distal end portion of the shaft and preventing direct electrical contact between the active and return electrodes; and

electrical conductors adapted for applying a radio-frequency voltage difference across the active and return electrodes,

wherein the active electrode and return electrode define an interconnecting passageway within the distal end portion of the shaft.

2. The electrosurgical apparatus of claim 1, wherein the return electrode comprises a lumen within the shaft.

3. The electrosurgical apparatus of claim 2, wherein the lumen and the interconnecting passage way comprises a continuous fluid conduit within the shaft.

4. The electrosurgical apparatus of claim 3, wherein the lumen is adapted for conveying an electrically conductive fluid into the interconnecting passageway at the distal end of the shaft.

5. The electrosurgical apparatus of claim 4, wherein the lumen is adapted for receiving electrically conducting fluid at the proximal end portion of the shaft.

6. The electrosurgical apparatus of claim 4, wherein the electrically conductive fluid is selected from the group consisting of isotonic saline, Ringer'"'"'s solution and other biocompatible ionic solutions.

7. The electrosurgical apparatus of claim 1, wherein plasma is generated on the active electrode upon application of the radio-frequency voltage across the active and return electrodes in the presence of an electrically conductive fluid.

8. The electrosurgical apparatus of claim 1, wherein an electric field is generated upon application of the radio-frequency voltage across the active and return electrodes, and wherein the electric field is directed from the active to the return electrode in the shaft.

9. The electrosurgical apparatus of claim 1, wherein the active electrode comprises one or more aperture therethrough for passing an electrically conductive fluid between the outside of the shaft to the return electrode.

10. The electrosurgical apparatus of claim 1, wherein the return electrode comprises a conductive cap exposed on the outer surface of the shaft, wherein the cap is spaced sufficiently from the active electrode to minimize generation of an electric arc between the active electrode and the cap.

11. The electrosurgical apparatus of claim 1, wherein the distal end of the shaft is sized for insertion into an intervertebral disc of a patient.

12. The electrosurgical apparatus of claim 1, wherein the shaft comprises an aspiration lumen having an inlet in the proximity of the electrodes for removing fluids form the distal end portion of the shaft.

13. An electrosurgical instrument for treating tissue within a body, comprising:

a shaft having a proximal end portion and a distal end portion;

an active electrode comprising a tissue-contacting surface on the distal end portion of the shaft;

a return electrode recessed within the tissue-contacting surface; and

an insulator separating the active and return electrodes,

wherein the tissue-contacting surface is adapted for generating plasma upon application of a radio frequency voltage across the active and return electrode in the presence of an electrically conducting fluid.

14. The instrument of claim 13, wherein the tissue-contacting surface and the return electrode define a chamber within the distal end portion of the shaft.

15. The instrument of claim 13, wherein the shaft comprises a fluid discharge lumen having a discharge port into the chamber.

16. The instrument of claim 13, wherein the shaft comprise a suction lumen having a suction port from the chamber.

17. The instrument of claim 13, wherein the active electrode defines an opening into the chamber.

18. The instrument of claim 13, wherein active electrode at least partly surrounds the return electrode.

19. The instrument of claim 17, wherein the active electrode comprises one or more holes opening into the chamber for fluid flows between the active and return electrodes.

20. The instrument of claim 16, wherein the return electrode comprises the suction lumen.

21. The instrument of claim 13, wherein the active electrode comprises the tissue-contacting surface.

22. The instrument of claim 13, wherein the active electrode has an annular configuration around the shaft.

23. The instrument of claim 13, wherein the active and return electrodes are coupled to the radio-frequency power supply by one or more connectors.

24. The instrument of claim 13, wherein return electrode extends to a return electrode cap on the shaft at a location sufficiently spaced from the tissue-contacting surface to prevent an electrical circuit between the active electrode and the return electrode cap.

25. A system for performing an electrosurgical procedure on a body tissue using plasma, the system comprising:

an electrosurgical instrument comprising a shaft;

an electrically conductive fluid supply having a discharge port on a distal end of the shaft; and

a radio-frequency voltage supply connected to the electrosurgical instrument, wherein the shaft comprises;

an active electrode on the distal end;

a return electrode recessed within the shaft;

an electrical insulator separating the active and return electrode; and

a chamber in communication with the active and return electrodes within the shaft, wherein on applying the radio-frequency voltage supply to the active and return electrodes in the presence and electrically conductive fluid, plasma is generated on the active electrode, and electric fields generated between the active and return electrodes are mostly contained within the shaft.

26. The system of claim 25, wherein the body tissue comprises an intervertebral disc.

27. The system of claim 25, wherein the conductive fluid supply comprises a fluid delivery element that forms an electrically conductive fluid path in contact with the active electrode and the return electrode.

28. The system of claim 25, wherein the distal end portion of the shaft is sized for insertion into an intervertebral disc.

29. The system of claim 25, wherein the active electrode comprises a portion of the external surface of the shaft.

30. The system of claim 27, wherein the fluid delivery element comprises a fluid supply lumen extending through the shaft, the fluid supply lumen comprising an inlet port into the conductive fluid supply, and a discharge port in the proximity of the active electrode.

31. The system of claim 27, wherein the fluid delivery element comprises a fluid supply instrument separate from the shaft.

32. The system of claim 25, wherein a fluid aspiration lumen for aspirating fluid from a region around the active electrode is provided for removing fluid in the vicinity of the active electrode.

33. The system of claim 32, wherein the fluid aspiration element comprises a suction lumen extending through the shaft, the suction lumen having an inlet in the vicinity of the active electrode.

34. The apparatus of claim 25, wherein the active electrode comprises one or more openings positioned over the chamber for passing electrically conductive fluid into the chamber.

35. The apparatus of claim 25, wherein an electrically insulating support member is located within the shaft for isolating the active electrode from the return electrode.

36. A method of treating nerve-sensitive tissue in the body, comprising:

positioning a distal end portion of an electrosurgical instrument in close proximity to the tissue, the distal end comprising an active electrode and a return electrode, wherein the active electrode comprises a tissue-contacting surface on the distal end portion, and the return electrode is recessed within the tissue-contacting surface;

applying a radio frequency voltage across the active and return electrodes in the presence of an electrically conductive fluid sufficient to generate plasma on the active electrode; and

contacting the tissue with the plasma.

37. The method of claim 36, wherein the return electrode is enclosed within the shaft, and wherein a fluid passageway is formed within the shaft between the active electrode and the return electrode.

38. The method of claim 36, wherein the conductive fluid is in contact with the active and return electrode through the fluid passageway.

39. The method of claim 36, wherein the conductive fluid is supplied from a fluid supply lumen located on the instrument.

40. The method of claim 36, wherein the conductive fluid is selected from the group consisting of isotonic saline, Ringer'"'"'s solution, and body fluids.

41. The method claims 36, wherein fluids in the vicinity of the active and return electrodes are removed by a suction lumen comprising a suction port located in the proximity of the active electrode.

42. The method of claim 36, wherein the body tissue comprises an intervertebral disc.

43. The method of claim 36, wherein treating nerve-sensitive tissue comprises coblating, heating, ablation, coagulation, cutting, removal, puncturing, probing, and otherwise stimulating the tissue.