ELECTROSURGICAL APPARATUS WITH LOW WORK FUNCTION ELECTRODE

• US 20120083782A1
• Filed: 10/04/2010
• Published: 04/05/2012
• Est. Priority Date: 10/04/2010
• Status: Abandoned Application

• Current Assignee: ArthroCare Corporation (Smith & Nephew PLC)
• Original Assignee: ArthroCare Corporation (Smith & Nephew PLC)
• Inventors: Stalder, Kenneth R., Woloszko, Jean, Christensen, Richard
• Application Number:
  US12/897,311
• Publication Number:
  US 20120083782A1
• Time in Patent Office: Days
• US Class Current: 606/41
• 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 2018/00125 with nanostructure
• CPC Class Codes: A61B 2018/00577 Ablation
• CPC Class Codes: A61B 2018/1472 for use with liquid electrolyte, e.g. virtual electrodes

Abstract

An electrosurgical apparatus includes an active electrode with a low-work function coating to improve ablation performance. Low-work function coatings include compounds of alkali metals and alkali earth metals. Additionally, the active electrode may include various micro-structures or asperities or nano-structures or asperities. An array of carbon nanotubes may be aligned and secured on the active electrode. A return electrode comprises a high-work function coating to suppress electrical discharge activity on the return electrode.

Claims

1. An electrosurgical apparatus for treating tissue at a target site comprising:

a shaft having a distal end and a proximal end,

an active electrode disposed near the distal end; and

a return electrode wherein when a voltage difference is applied between the active electrode and the return electrode in the presence of an electrically conductive fluid a current path is formed therebetween and wherein the active electrode comprises a low-work function surface to enhance electrical discharge activity.

2. The electrosurgical apparatus of claim 1 wherein said low-work function surface further comprises at least one of micro-structures, micro-asperities, nano-asperities, and nano-structures.

3. The electrosurgical apparatus of claim 2 wherein said low-work function surface comprises nano-structures and said nano-structures comprise tubular shapes.

4. The electrosurgical apparatus of claim 3 wherein said nano-structures are disposed in an aligned formation.

5. The electrosurgical apparatus of claim 1 wherein said low-work function surface is biocompatible and insoluble in a saline.

6. The electrosurgical apparatus of claim 1 wherein said low-work function surface has a work function less than or equal to 3 eV.

7. The electrosurgical apparatus of claim 1 wherein said low-work function surface comprises a layer comprising an alkali metal or alkaline earth metal.

8. The electrosurgical apparatus of claim 1 wherein said active electrode is comprised of a metal doped with a rare earth element, thereby forming a low-work function surface.

9. The electrosurgical apparatus of claim 1 wherein said return electrode comprises a high-work function surface for decreasing discharge activity.

10. The electrosurgical apparatus of claim 9 wherein said high-work function material comprises platinum, iridium, osmium, palladium or gold.

11. An electrosurgical apparatus for treating tissue at a target site comprising:

a shaft having a distal end and a proximal end,

an active electrode disposed near the distal end; and

a return electrode wherein when a voltage difference is applied between the active electrode and the return electrode in the presence of an electrically conductive fluid a current path is formed therebetween and wherein the return electrode comprises a high-work function surface to suppress electrical discharge activity.

12. The electrosurgical apparatus of claim 11 wherein said active electrode comprises a surface comprising at least one of micro-structures, micro-asperities, nano-asperities, and nano-structures.

13. The electrosurgical apparatus of claim 12 wherein said nano-structures comprise tubular shapes.

14. The electrosurgical apparatus of claim 12 wherein said active electrode comprises a low-work function layer for increasing discharge activity.

15. The electrosurgical apparatus of claim 14 wherein said low-work function material comprises at least one compound from the group consisting of alkali metals and alkali earth metals.

16. The electrosurgical apparatus of claim 14 wherein said low-work function surface layer is biocompatible and insoluble in a saline.

17. The electrosurgical apparatus of claim 14 wherein said low-work function surface has a work function less than or equal to 3 eV.

18. The electrosurgical apparatus of claim 11 wherein said high-work function material comprises platinum, iridium, osmium, palladium or gold.

19. The electrosurgical apparatus of claim 16 wherein said surface layer comprises barium oxide.

20. The electrosurgical apparatus of claim 11 wherein said return electrode is positioned on the shaft.

21. An electrosurgical apparatus for treating tissue at a target site comprising:

a shaft having a distal end and a proximal end,

an active electrode disposed near the distal end; and

a return electrode wherein when a voltage difference is applied between the active electrode and the return electrode in the presence of an electrically conductive fluid a current path is formed therebetween and wherein said active electrode comprises a surface comprising at least one of micro-structures, micro-asperities, nano-asperities, and nano-structures to enhance electrical discharge activity.

22. The electrosurgical apparatus of claim 21 wherein the active electrode has a low-function surface.

23. The electrosurgical apparatus of claim 22 wherein said low-work function surface comprises nano-structures and said nano-structures comprise tubular shapes.

24. The electrosurgical apparatus of claim 23 wherein said nano-structures are disposed in an aligned formation.

25. The electrosurgical apparatus of claim 21 wherein said low-work function surface is biocompatible and insoluble in a saline.

26. The electrosurgical apparatus of claim 21 wherein said low-work function surface has a work function less than or equal to 3 eV.

27. The electrosurgical apparatus of claim 21 wherein said low-work function surface comprises an element selected from the group consisting of an alkali metal or alkaline earth metals.

28. The electrosurgical apparatus of claim 21 wherein said active electrode is comprised of a metal doped with a rare earth element, thereby forming a low-work function surface.

29. The electrosurgical apparatus of claim 21 wherein said return electrode comprises a high-work function surface for suppressing discharge activity.

30. The electrosurgical apparatus of claim 29 wherein said high-work function material comprises platinum, iridium, osmium, palladium or gold.