Cartilage treatment probe

• US 20050245925A1
• Filed: 11/30/2004
• Published: 11/03/2005
• Est. Priority Date: 01/31/2003
• Status: Active Grant

• Current Assignee: Smith & Nephew Incorporated (Smith & Nephew PLC)
• Original Assignee: Smith & Nephew Incorporated (Smith & Nephew PLC)
• Inventors: Lu, Yan, Iki, Kobi, Ranalli, Richard M., Mitchell, Mathew E., Ambrisco, William M., Edwards, Ryland B. III, Lorang, Douglas M., Markel, Mark, Gannon, Alan P., Meyer, Marie
• Granted Patent: US 8,066,700 B2
• Time in Patent Office: Days
• US Class Current: 606/41
• CPC Class Codes: A61B 18/1402 Probes for open surgery

Abstract

An electrosurgical instrument includes a shaft, a flexible portion, and a head coupled to the shaft through the flexible portion and pivotably coupled to the flexible portion. The head includes a non-conductive surface and an electrically conductive surface. The flexible portion is configured to bias the non-conductive surface and the electrically conductive surface towards a tissue surface, such as cartilage. The non-conductive surface may include a material having a thermal conductivity less than or equal to about 30 W/m*K and/or a volume resistivity greater than or equal to about 1×10¹⁴ ohm*cm. The non-conductive surface may include a ceramic such as Macor® ceramic, ZTA ceramic, and/or 99.5% alumina ceramic.

Claims

1. An electrosurgical instrument comprising:

a shaft;

a flexible portion; and

a head coupled to the shaft through the flexible portion and pivotably coupled to the flexible portion, the head including a non-conductive surface and an electrically conductive surface,

wherein the flexible portion is configured to bias the non-conductive surface and the electrically conductive surface towards a tissue surface.

2. The electrosurgical instrument of claim 1 wherein the non-conductive surface and the electrically conductive surface form a substantially planar tissue contact surface.

3. The electrosurgical instrument of claim 2 wherein the non-conductive surface is adjacent at least a portion of the electrically conductive surface.

4. The electrosurgical instrument of claim 1 wherein the non-conductive surface comprises a material having a thermal conductivity less than or equal to about 30 W/m*K.

5. The electrosurgical instrument of claim 1 wherein the non-conductive surface comprises a material having a volume resistivity greater than or equal to about 1×

10¹⁴ ohm*cm.

6. The electrosurgical instrument of claim 1 wherein the non-conductive surface comprises a ceramic.

7. The electrosurgical instrument of claim 1 wherein the non-conductive surface comprises Macor®

ceramic.

8. The electrosurgical instrument of claim 1 wherein the non-conductive surface comprises ZTA ceramic.

9. The electrosurgical instrument of claim 1 wherein the non-conductive surface comprises 99.5% alumina ceramic.

10. The electrosurgical instrument of claim 1 wherein the tissue surface comprises cartilage and the non-conductive surface comprises a material selected so that when the electrically conductive surface is used to apply about 10 to 15 watts of radiofrequency energy in an ablative mode to a one square centimeter area of the cartilage for about 15 seconds in a paintbrush treatment pattern with the head being moved at approximately 5 mm/sec, a mean depth of chondrocyte death is less than or equal to about 176 μ

m.

11. The electrosurgical instrument of claim 1 wherein the tissue surface comprises cartilage and the non-conductive surface comprises a material selected so that when the electrically conductive surface is used to apply about 10 to 15 watts of radiofrequency energy in an ablative mode to a one square centimeter area of the cartilage for about 15 seconds in a paintbrush treatment pattern with the head being moved at approximately 5 mm/sec, a maximum depth of chondrocyte death than is less than or equal to about 231 μ

m.

12. An electrosurgical instrument comprising:

a shaft;

a resiliently flexible portion; and

a head coupled to the shaft through the resiliently flexible portion, the head being pivotably coupled to the resiliently flexible portion, the head including a substantially planar tissue contact surface including a non-conductive portion and an electrically conductive portion.

13. The electrosurgical instrument of claim 12 wherein the non-conductive portion comprises a material having a thermal conductivity less than or equal to about 30 W/m*K and a volume resistivity greater than or equal to about 1×

10¹⁴ ohm*cm.

14. The electrosurgical instrument of claim 12 wherein the non-conductive portion comprises Macor®

ceramic.

15. The electrosurgical instrument of claim 12 wherein the non-conductive portion comprises ZTA ceramic.

16. The electrosurgical instrument of claim 12 wherein the non-conductive portion comprises 99.5% alumina ceramic.

17. A method of treating chondromalacia comprising:

positioning a non-conductive surface and an electrically conductive surface adjacent to a cartilage surface, where both the non-conductive surface and the electrically conductive surface are part of a head of an instrument, the head being pivotable relative to a shaft of the instrument;

moving the shaft relative to the cartilage surface, whereby the head pivots relative to the cartilage surface; and

applying electrical energy to the electrically conductive surface to treat chondromalacia.

18. The method of claim 17 wherein moving the shaft results in the head sliding across the cartilage surface as the head pivots.

19. The method of claim 17 wherein the non-conductive surface comprises a material having a thermal conductivity less than or equal to about 30 W/m*K.

20. The method of claim 19 wherein the material has a volume resistivity greater than or equal to about 1×

10¹⁴ ohm*cm.

21. The method of claim 17 wherein the material comprises a ceramic.

22. The method of claim 17 wherein the non-conductive surface comprises Macor®

ceramic.

23. The method of claim 17 wherein the non-conductive surface comprises ZTA ceramic.

24. The method of claim 17 wherein the non-conductive surface comprises 99.5% alumina ceramic.