Cartilage treatment probe

• US 8,066,700 B2
• Filed: 11/30/2004
• Issued: 11/29/2011
• 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: Meyer, Marie, 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.
• Primary Examiner(s): Peffley; Michael
• Assistant Examiner(s): HUPCZEY, JR, RONALD JAMES
• Application Number:
  US10/999,230
• Publication Number:
  US 20050245925A1
• Time in Patent Office: 2,555 Days
• Field of Search: 606 41- 50
• 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 having a proximal end and a distal end and defining a first longitudinal axis between the proximal and distal ends;

a flexible portion having a first end and a second end, the first and second ends of the flexible portion directly attached to an end of the shaft; and

a head having a proximal end and a distal end and defining a second longitudinal axis between the proximal and distal ends, the proximal end of the head being closer to the distal end of the shaft than the distal end of the head, a part of the flexible portion received by a portion of the head such that the head is free to pivot about an axis, defined by the part of the flexible portion, that is substantially transverse to the longitudinal axis of the shaft, the head including a substantially planar, flat non-conductive surface and an electrically conductive surface, the non-conductive surface formed from one or more of ceramic, plastic, alumina, aluminum nitride, or zirconia, and the electrically conductive surface having at least a portion recessed in or projecting from the substantially planar, flat non-conductive surface,

wherein the flexible portion is configured to passively bias the non-conductive surface and the electrically conductive surface towards a tissue surface such that, prior to contacting the tissue surface, the second longitudinal axis is offset from the first longitudinal axis by an angle α

.

2. 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.

3. 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.

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

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

ceramic.

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

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

8. 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.

9. 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.

10. The instrument of claim 1, wherein the electrically conductive surface has a first surface area of between about 0.0009 to 0.0036 square inches and the substantially planar, flat non-conductive surface has a second surface area of between about 0.01 to 0.057 square inches.

11. The instrument of claim 1, further comprising a flexible power lead coupled between the shaft and the electrically conductive surface.

12. An electrosurgical instrument comprising:

a shaft having a proximal end and a distal end and defining a first longitudinal axis between the proximal and distal ends;

a resiliently flexible portion having a first end and a second end, the first and second ends of the flexible portion directly attached to the distal end of the shaft; and

a head having a proximal end and a distal end and defining a second longitudinal axis between the proximal and distal ends, the proximal end of the head being closer to the distal end of the shaft than the distal end of the head, a part of the flexible portion received by a portion of the head such that the head is free to pivot about an axis, defined by the part of the flexible portion, that is substantially transverse to the longitudinal axis of the shaft, the head including a substantially planar tissue contact surface including a substantially planar, flat non-conductive portion and an electrically conductive portion, the non-conductive portion formed from one or more of ceramic, plastic, alumina, aluminum nitride, or zirconia, and the electrically conductive portion recessed in or projecting from the non-conductive portion,

wherein the resiliently flexible portion is configured to passively bias the non-conductive portion and the electrically conductive portion towards a tissue surface such that, prior to contacting the tissue surface, the second longitudinal axis is offset from the first longitudinal axis by an angle α

.

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. The instrument of claim 12, wherein the electrically conductive surface has a first surface area of between about 0.0009 to 0.0036 square inches and the substantially planar, flat non-conductive surface has a second surface area of between about 0.01 to 0.057 square inches.

18. The instrument of claim 12, further comprising a flexible power lead coupled between the shaft and the electrically conductive surface.

19. An electrosurgical instrument comprising:

a shaft having a proximal end and a distal end and defining a first longitudinal axis between the proximal and distal ends;

a flexible portion having a first end and a second end, the first and second ends of the flexible portion directly attached to the distal end of the shaft; and

a head having a proximal end and a distal end and defining a second longitudinal axis between the proximal and distal ends, the proximal end of the head being closer to the distal end of the shaft than the distal end of the head, a part of the flexible portion received by a portion of the head such that the head is free to pivot about an axis, defined by the part of the flexible portion, that is substantially transverse to the longitudinal axis of the shaft, the head including a substantially planar, flat non-conductive surface and an electrically conductive surface, the non-conductive surface formed from one or more of ceramic, plastic, alumina, aluminum nitride, or zirconia, and the electrically conductive surface having at least a portion recessed in or projecting from the substantially planar, flat non-conductive surface, the non-conductive surface sized to limit how far the electrically conductive surface can advance into tissue such that the tissue effect is limited to one or more of debriding, smoothing, and sealing the tissue,

wherein the flexible portion is configured to passively bias the non-conductive surface and the electrically conductive surface towards a tissue surface such that, prior to contacting the tissue surface, the second longitudinal axis is offset from the first longitudinal axis by an angle α

.

20. The instrument of claim 19, wherein the electrically conductive surface has a first surface area of between about 0.0009 to 0.0036 square inches and the substantially planar, flat non-conductive surface has a second surface area of between about 0.01 to 0.057 square inches.

21. The instrument of claim 19, further comprising a flexible power lead coupled between the shaft and the electrically conductive surface.

22. An electrosurgical instrument comprising:

a shaft having a proximal end and a distal end and defining a first longitudinal axis between the proximal and distal ends;

a flexible portion having a first end and a second end, the first and second ends of the flexible portion directly attached to the distal end of the shaft; and

a head having a proximal end and a distal end and defining a second longitudinal axis between the proximal and distal ends, the proximal end of the head being closer to the distal end of the shaft than the distal end of the head, a part of the flexible portion received by a portion of the head such that the head is free to pivot about an axis, defined by the part of the flexible portion, that is substantially transverse to the longitudinal axis of the shaft, the head including an electrically conductive surface and a substantially planar, flat non-conductive surface, the non- conductive surface formed from one or more of ceramic, plastic, alumina, aluminum nitride, or zirconia, and the electrically conductive surface having at least a portion recessed in or projecting from the substantially planar, flat non-conductive surface, the head being configured and shaped such that the head is free to pivot about the flexible portion such that during use the electrode is maintained in contact with a tissue surface as the head moves across the tissue surface,

wherein the flexible portion is configured to passively bias the non-conductive surface and the electrically conductive surface towards a tissue surface such that, prior to contacting the tissue surface, the second longitudinal axis is offset from the first longitudinal axis by an angle α

.

23. The instrument of claim 22, wherein the electrically conductive surface has a first surface area of between about 0.0009 to 0.0036 square inches and the substantially planar, flat non-conductive surface has a second surface area of between about 0.01 to 0.057 square inches.

24. The instrument of claim 22, further comprising a flexible power lead coupled between the shaft and the electrically conductive surface.

25. An electrosurgical instrument comprising:

a shaft having a proximal end and a distal end and defining a first longitudinal axis between the proximal and distal ends;

a flexible portion having a first end and a second end, the first and second ends of the flexible portion directly attached to the distal end of the shaft; and

a head comprising length, width, and height dimensions, and comprising a proximal end and a distal end and defining a second longitudinal axis between the proximal and distal ends, the length dimension being defined between the proximal and distal ends of the head and the proximal end of the head being closer to the distal end of the shaft than the distal end of the head, the head comprising a substantially planar, flat first surface, a part of the flexible portion received by a portion of the head such that the head is free to pivot about the flexible portion,

wherein the flexible portion is configured to passively bias the substantially planar, flat first surface towards a tissue surface such that, prior to contacting the tissue surface, the second longitudinal axis is offset from the first longitudinal axis by an angle α

and the length of the head is greater than the width or height of the head.

26. The instrument of claim 25, wherein the first surface is non-conductive and the head further comprises an electrically conductive surface having at least a portion recessed in or projecting from the first surface.

27. The instrument of claim 25, wherein the head is free to pivot about an axis, defined by the part of the flexible portion, that is substantially transverse to the shaft.

28. An electrosurgical instrument comprising:

a shaft having a proximal end and a distal end and defining a first longitudinal axis between the proximal and distal ends;

a flexible portion having a first end and a second end, the first and second ends of the flexible portion directly attached to the distal end of the shaft; and

a head having a substantially planar, flat non-conductive first surface and an electrically conductive surface having at least a portion recessed in or projecting from the first surface, a second surface opposing the first surface, and opposing side surfaces extending between the first and second surfaces, the head having a proximal end and a distal end and defining a second longitudinal axis between the proximal and distal ends, the proximal end of the head being closer to the distal end of the shaft than the distal end of the head, the head defining openings in the opposing side surfaces that receive a part of the flexible portion such that the head is free to pivot about the flexible portion,

wherein the flexible portion is configured to passively bias the substantially planar, flat non-conductive first surface and the electrically conductive surface towards a tissue surface such that, prior to contacting the tissue surface, the second longitudinal axis is offset from the first longitudinal axis by an angle α

.

29. The instrument of claim 28, wherein the head defines a slot that is transverse to the longitudinal axis of the shaft and terminates at the openings defined in the opposing side surfaces.

30. The instrument of claim 29, wherein the flexible portion enters a first of the openings in a first of the opposing side surfaces, passes through the slot, and exits through the second of the openings in a second of the opposing side surfaces.