Methods and apparatus for treating back pain

1. A method for treating discogenic pain, comprising:

a) advancing an electrosurgical probe comprising an energy-applying element from a location outside an intervertebral disc towards a nucleus pulposus of the disc;

b) positioning said energy-applying element within the nucleus pulposus of the disc;

c) electrosurgically treating the nucleus pulposus of the disc by applying a first high frequency voltage at the energy-applying element;

d) positioning said energy-applying element within the posterior of the annulus fibrosus; and

e) electrosurgically coagulating nerve tissue within the posterior of the annulus fibrosus by applying heat using said energy-applying element, whereby the pain is alleviated.

2. The method of claim 1 , wherein the probe includes a shaft having a steerable shaft distal end, and said step d) comprises steering the shaft distal end towards the posterior of the annulus fibrosus.

3. The method of claim 1 , wherein said step d) comprises positioning the energy-applying element without contacting or passing through the nucleus pulposus of the disc.

4. The method of claim 1 , wherein said step e) comprises applying a high frequency voltage between the energy-applying element and a return electrode.

5. The method of claim 4 , wherein the probe includes a temperature sensor for monitoring a temperature of the annulus fibrosus, and the method further comprises adjusting the high frequency voltage applied between the energy-applying element and the return electrode in response to a sensed temperature.

6. The method of claim 1 , wherein the probe includes a shaft and an electrode assembly disposed at the shaft distal end, the electrode assembly including the energy-applying element and a return electrode, and wherein said step c) comprises applying a high frequency voltage between the energy-applying element and the return electrode.

7. The method of claim 1 , wherein said step e) comprises electrosurgically heating a portion of the posterior of the annulus fibrosus to a temperature sufficient to inactive unmyelinated nerve fibers within the posterior of the annulus fibrosus.

8. The method of claim 7 , wherein the temperature is insufficient to cause contraction of collagen fibers within the annulus fibrosus.

9. The method of claim 1 , wherein said step e) comprises inactivating one or more branches of the sinuvertebral nerve within the annulus fibrosus.

10. The method of claim 1 , wherein said step e) comprises electrosurgically heating a portion of the annulus fibrosus to a temperature in the range of from about 43° C. to about 53° C.

11. The method of claim 1 , wherein said step e) comprises electrosurgically heating a portion of the annulus fibrosus to a temperature in the range of from about 45° C. to about 50° C.

12. The method of claim 1 , wherein said step e) comprises inactivating nociceptors within the annulus fibrosus.

13. The method of claim 1 further comprising:

positioning said energy applying element within the annulus fibrosus and ablating nervous tissue within the annulus fibrosus.

14. The method of claim 1 , wherein the energy-applying element comprises an active electrode.

15. A method for treating discogenic pain, comprising:

a) advancing an electrosurgical probe comprising an energy-applying element from a location outside an intervertebral disc towards an annulus fibrosus of the disc;

b) positioning said energy-applying element within the posterior of the annulus fibrosus and positioning a return electrode adjacent to an external surface of the posterior region of the annulus fibrosus; and

c) electrosurgically coagulating nerve tissue within the posterior of the annulus fibrosus by applying heat using said energy-applying element, whereby the pain is alleviated.

16. The method of claim 15 , wherein said step b) comprises positioning the return electrode at a location external to the disc.

17. The method of claim 15 , wherein said step b) comprises positioning the energy-applying element within the annulus fibrosus adjacent to the nucleus pulposus.

18. The method of claim 16 , wherein the energy-applying element is disposed on a first shaft and the return electrode is disposed on a second shaft.

19. A method for denervating an intervertebral disc, comprising:

a) advancing an electrosurgical probe comprising an energy-applying element from a location outside an intervertebral disc towards a nucleus pulposus of the disc;

b) positioning said energy-applying element within the nucleus pulposus of the disc;

c) electrosurgically treating the nucleus pulposus of the disc by applying a first high frequency voltage at the energy-applying element;

d) advancing the energy-applying element of an electrosurgical instrument from a location outside the disc towards a posterior region of an annulus fibrosus of the disc;

e) positioning the energy-applying element within the annulus fibrosus; and

f) applying a high frequency voltage between the energy-applying element and a return electrode to coagulate tissue within the annulus fibrosus, wherein the posterior region of the annulus fibrosus is denervated.

20. The method of claim 19 , wherein said step a) comprises accessing the disc in an open procedure.

21. The method of claim 20 , wherein accessing the disc comprises:

forming an incision in the patient's back;

dissecting the underlying tissue to the lamina; and

removing a portion of the lamina.

22. The method of claim 20 , wherein the open procedure comprises stabilizing the spine.

23. The method of claim 22 , wherein stabilizing the spine comprises fusing together two or more adjacent vertebrae.

24. The method of claim 19 , wherein said step a) comprises accessing the disc percutaneously.

25. The method of claim 19 , wherein said step a) comprises advancing the energy-applying element towards the disc via a posterolateral approach.

26. The method of claim 19 , wherein said step f) comprises applying the high frequency voltage in the range of from about 20 volts RMS to about 90 volts RMS.

27. The method of claim 19 , wherein said step f) effects heating of the annulus fibrosus in a region adjacent to the energy-applying element to a temperature in the range of from about 45° C. to 50° C.

28. The method of claim 19 , wherein the energy-applying element is disposed on a distal end of a first shaft, and wherein said step e) comprises positioning the distal end of the first shaft within the annulus fibrosus at a location adjacent to the posterior of the nucleus pulposus of the disc.

29. The method of claim 19 , wherein said energy-applying element comprises an active electrode.

30. A method for denervating an intervertebral disc, comprising:

a) advancing the energy-applying element of an electrosurgical instrument from a location outside the disc towards a posterior region of an annulus fibrosus of the disc, wherein the energy-applying element is disposed on a distal end of a first shaft;

b) positioning the energy-applying element within the annulus fibrosus at a location adjacent to the posterior of the nucleus pulposus of the disc;

c) applying a high frequency voltage between the energy-applying element and a return electrode to coagulate tissue within the annulus fibrosus, wherein the posterior region of the annulus fibrosus is denervated, and wherein the return electrode is disposed on a distal end of a second shaft; and

d) advancing the distal end of the second shaft to a location adjacent to an outer wall of the annulus fibrosus.

31. The method of claim 30 , wherein the return electrode is positioned external to the disc.

32. A method for treating an intervertebral disc, comprising:

a) advancing a first electrosurgical probe comprising a first energy-applying element from a location outside an intervertebral disc towards a nucleus pulposus of the disc;

b) positioning said first energy-applying element within the nucleus pulposus of the disc;

c) electrosurgically treating the nucleus pulposus of the disc by applying a first high frequency voltage at the first energy-applying element;

d) advancing an energy-applying element of a second electrosurgical instrument from a location outside the intervertebral disc into the annulus fibrosus; and

e) electrosurgically coagulating collagen within the posterior of the annulus fibrosus by applying heat with a second energy-applying element of said second electrosurgical instrument.

33. The method of claim 32 , wherein said step e) comprises inactivating nociceptors within the posterior of the annulus fibrosus.

34. The method of claim 32 , wherein said step e) comprises applying a high frequency voltage between the second energy-applying element and the second return electrode, wherein the second instrument is operating in a sub-ablation mode.

35. The method of claim 32 , wherein said step e) comprises coagulating nerve fibers within the posterior of the annulus fibrosus.

36. The method of claim 35 , wherein said step e) comprises electrosurgically heating a posterior region of the annulus fibrosus to a temperature in the range of from about 45° C. to about 50° C.

37. The method of claim 32 , wherein said energy-applying element is adapted for delivering a controlled depth of thermal heating of the tissue surrounding said disc.

38. A method for treating back pain, comprising:

a) electrosurgically applying heat at a target tissue within a posterior region of an annulus fibrosus of an intervertebral disc via an electrosurgical probe;

b) controlling the temperature to which the target tissue is exposed, such that the target tissue is exposed to a temperature in the range of from about 43° C. to 53° C.; and

c) as a result of said steps a) and b), denervating at least a portion of the target tissue by coagulating nerve tissue therein, whereby the pain is alleviated; and

wherein the probe includes an active electrode disposed on a working end of a first shaft of the probe and a return electrode disposed on a working end of a second shaft of the probe, and, prior to step a), the method further comprises:

d) advancing the working end of the first shaft through a portion of the annulus fibrosus such that the active electrode is positioned within the annulus fibrosus at a first location adjacent to the posterior of the nucleus pulposus; and

e) advancing the working end of the second shaft towards the posterior of the annulus fibrosus such that the return electrode is positioned external to the annulus fibrosus at a second location adjacent to the posterior of the disc.

39. A method for treating an intervertebral disc, comprising:

a) providing an electrosurgical instrument, the instrument having a first shaft and a second shaft, the first shaft having a first electrode disposed at the first shaft distal end, and the second shaft having a second electrode disposed at the second shaft distal end;

b) positioning the first electrode at a first location, the first location within the annulus fibrosus adjacent to a posterior region of a nucleus pulposus of the disc;

c) positioning the second electrode at a second location, the second location spaced from the first location in a direction towards the posterior of the disc; and

d) applying a high frequency voltage between the first electrode and the second electrode, wherein a portion of the annulus fibrosus is at least partially denervated.

40. The method of claim 39 , wherein the second location is spaced from the first location by a distance in the range of from about 1 mm to 1 cm.

41. The method of claim 39 , wherein the second electrode is positioned external to the posterior of the disc.