Apparatus for thermal treatment of an intervertebral disc

1. A method for relieving pain associated with an intervertebral disc having a nucleus pulposus and an annulus fibrosus surrounding the nucleus pulposus, comprising the steps of:

introducing a thermal transmitting element of a thermal probe into the annulus fibrosus of the intervertebral disc, the thermal probe defining proximal and distal ends and having a guidable region adjacent the distal end thereof the guidable region characterized by having sufficient rigidity to advance within the annulus fibrosus of the intervertebral disc in response to an axial force exerted on the proximal end of the thermal probe while having sufficient flexibility to substantially follow and conform to an azimuthal course defined by the natural striata of the annulus fibrosus;

advancing the thermal transmitting element of the thermal probe within the annulus fibrosus while avoiding the nucleus pulposus; and

supplying thermal energy from a thermal energy source to the thermal transmitting element to heat the annulus fibrosus adjacent the transmitting element while avoiding directly heating the nucleus pulposus sufficiently to relieve pain associated with the intervertebral disc.

2. The method according to claim 1 wherein the thermal probe includes a flexible probe portion, whereby the flexible probe portion follows a generally arcuate path within the annulus fibrosus.

3. The method according to claim 2 wherein the step of advancing the thermal transmitting element of the thermal probe includes passing the flexible probe portion generally along an arcuate path defined by natural striata of the annulus fibrosus.

4. The method according to claim 1 wherein the step of advancing includes positioning the thermal transmitting element adjacent at least one of a posterior section, lateral section and posterior-lateral section of the annulus fibrosus.

5. The method according to claim 4 , including the step of accessing the annulus fibrosus from a posterior-lateral section of the intervertebral disc.

6. The method according to claim 1 further including the step of positioning a cannula adjacent the intervertebral disc and passing the thermal probe through a lumen of the cannula into the annulus fibrosus.

7. The method according to claim 6 wherein the cannula includes an arcuate portion adjacent a distal end thereof and wherein, during the step of advancing the thermal probe, the arcuate cannula portion guides the flexible probe portion along the path through the the annulus fibrosus.

8. The method according to claim 7 wherein the step of positioning includes at least partially introducing the distal end of the cannula into the annulus fibrosus.

9. The method according to claim 8 further including the step of angulating the arcuate portion to a desired orientation within the annulus fibrosus.

10. The method according to claim 1 further including the step of monitoring impedance of tissue to detect variations in tissue-type to thereby facilitate positioning of the thermal transmitting element in the annulus fibrosus.

11. The method according to claim 1 further including the step of monitoring the position of at least the thermal transmitting element with imaging means.

12. A method for relieving pain associated with an intervertebral disc, the intervertebral disc having a disc nucleus and an annulus fibrosus surrounding the disc nucleus, the method comprising the steps of:

accessing an intervertebral disc with a cannula;

advancing a thermal probe having a heat transmitting region through the cannula into the intervertebral disc and within the annulus fibrosus while avoiding the disc nucleus to, position the heat transmitting region of the thermal probe in at least one of posterior, lateral and posterior-lateral areas of the annulus fibrosus, the thermal probe defining proximal and distal ends and having a guidable region adjacent the distal end thereof, the guidable region characterized by having sufficient rigidity to advance within the annulus fibrosus of the intervertebral disc in response to an axial force exerted on the proximal end of the thermal probe while having sufficient flexibility to substantially follow and conform to an azimuthal course defined by the natural striata of the annulus fibrosus; and

supplying thermal energy from a thermal energy source to the heat transmitting region to heat the annulus fibrosus while avoiding directly heating the disc nucleus to treat pain associated with the intervertebral disc.

13. The method according to claim 12 wherein the step of accessing includes advancing a distal end of the cannula through the intervertebral disc to position the distal end within the annulus fibrosus.

14. The method according to claim 13 wherein the cannula includes an arcuate portion adjacent the distal end thereof and further including the step of manipulating the arcuate portion to a desired orientation with respect to the annulus fibrosus.

15. The method according to claim 14 wherein the heat transmitting region of the thermal probe is substantially flexible and wherein during the step of advancing, the heat transmitting region bends within the arcuate portion of the cannula.

16. The method according to claim 13 wherein the cannula includes impedance means and wherein the step of accessing includes monitoring impedance of tissue to ascertain a location of the distal end of the cannula in relation to the intervertebral disc.

17. The method according to claim 16 wherein the step of monitoring impedance of tissue further includes monitoring a plurality of impedance interfaces including the tissue and a cortex of the intervertebral disc, the cortex and the annulus fibrosus of the intervertebral disc, and the annulus fibrosus and the disc nucleus of the intervertebral disc.