Methods and apparatus for treating back pain

Abstract

Apparatus and methods for treating back pain of a patient by denervation of an intervertebral disc or a region of the posterior longitudinal ligament by the controlled application of heat to a target tissue. In one embodiment, the invention may include a procedure combining both decompression of a disc, and denervation of the annulus fibrosus. In one embodiment, a method of the invention includes positioning an active electrode of an electrosurgical instrument in at least close proximity to an intervertebral disc, and applying at least a first high frequency voltage between the active electrode and a return electrode, wherein nervous tissue within the annulus fibrosus is inactivated, and discogenic pain of the patient is alleviated. In one embodiment, the invention includes positioning a first electrode of a dual-shaft electrosurgical instrument at a first location in relation to a target disc, positioning a second electrode of the instrument at a second location, and applying a high frequency voltage between the first and second electrodes, wherein the first and second electrodes are disposed on separate shafts of the instrument.

What is claimed is:  
     
         1 . A method for treating discogenic pain, comprising: 
 a) advancing an active electrode of an electrosurgical probe from a location outside an intervertebral disc towards an annulus fibrosus of the disc;    b) positioning the active electrode in at least close proximity to the annulus fibrosus; and    c) electrosurgically denervating at least a portion of the annulus fibrosus, 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 a) comprises steering the shaft distal end towards the posterior of the annulus fibrosus.  
     
     
         3 . The method of  claim 1 , wherein the active electrode is at a working end of the probe, and said step b) comprises positioning the active electrode within the posterior of the annulus fibrosus.  
     
     
         4 . The method of  claim 1 , wherein said step b) comprises positioning the active electrode within or adjacent to the annulus fibrosus without contacting or passing through a nucleus pulposus of the disc.  
     
     
         5 . The method of  claim 1 , wherein said step c) comprises applying a high frequency voltage between the active electrode and a return electrode.  
     
     
         6 . The method of  claim 5 , further comprising: 
 d) after said step c), repositioning the active electrode with respect to the annulus fibrosus; and    e) reapplying the high frequency voltage between the active electrode and the return electrode.    
     
     
         7 . 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 active electrode and a return electrode, and wherein said step c) comprises applying a high frequency voltage between the active electrode and the return electrode.  
     
     
         8 . The method of  claim 1 , wherein said step c) comprises electrosurgically heating a portion of the annulus fibrosus to a temperature sufficient to inactive unmyelinated nerve fibers within the annulus fibrosus.  
     
     
         9 . The method of  claim 8 , wherein the temperature is insufficient to cause contraction of collagen fibers within the annulus fibrosus.  
     
     
         10 . The method of  claim 1 , wherein said step c) comprises inactivating one or more branches of the sinuvertebral nerve within the annulus fibrosus.  
     
     
         11 . The method of  claim 1 , wherein said step c) comprises electrosurgically heating a portion of the annulus fibrosus to a temperature in the range of from about 43° C. to 53° C.  
     
     
         12 . The method of  claim 1 , wherein said step c) comprises electrosurgically heating a portion of the annulus fibrosus to a temperature in the range of from about 45° C. to 50° C.  
     
     
         13 . The method of  claim 1 , wherein said step c) comprises coagulating nervous tissue within the annulus fibrosus.  
     
     
         14 . The method of  claim 1 , wherein said step c) comprises inactivating nociceptors within the annulus fibrosus.  
     
     
         15 . The method of  claim 1 , wherein said step c) comprises ablating nervous tissue within the annulus fibrosus.  
     
     
         16 . The method of  claim 5 , 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 active electrode and the return electrode in response to a sensed temperature.  
     
     
         17 . The method of  claim 1 , wherein said step b) comprises positioning the active electrode within a posterior region of the annulus fibrosus, and the method further comprising positioning a return electrode adjacent to an external surface of the posterior region of the annulus fibrosus.  
     
     
         18 . The method of  claim 17 , wherein said step g) comprises positioning the return electrode at a location external to the disc.  
     
     
         19 . The method of  claim 17 , wherein said step b) comprises positioning the active electrode within the annulus fibrosus adjacent to the nucleus pulposus.  
     
     
         20 . The method of  claim 18 , wherein the active electrode is disposed on a first shaft and the return electrode is disposed on a second shaft.  
     
     
         21 . A method for denervating an intervertebral disc, comprising: 
 a) advancing an active electrode of an electrosurgical instrument from a location outside the disc towards a posterior region of an annulus fibrosus of the disc;    b) positioning the active electrode in at least close proximity to the posterior region of the annulus fibrosus; and    c) applying a high frequency voltage between the active electrode and a return electrode, wherein the posterior region of the annulus fibrosus is denervated.    
     
     
         22 . The method of  claim 21 , wherein said step a) comprises accessing the disc in an open procedure.  
     
     
         23 . The method of  claim 22 , wherein accessing the disc comprises: 
 d) forming an incision in the patient's back;    e) dissecting the underlying tissue to the lamina; and    f) removing a portion of the lamina.    
     
     
         24 . The method of  claim 22 , wherein the open procedure comprises stabilizing the spine.  
     
     
         25 . The method of  claim 24 , wherein stabilizing the spine comprises fusing together two or more adjacent vertebrae.  
     
     
         26 . The method of  claim 21 , wherein said step a) comprises accessing the disc percutaneously.  
     
     
         27 . The method of  claim 21 , wherein said step a) comprises advancing the active electrode towards the disc via a posterolateral approach.  
     
     
         28 . The method of  claim 21 , wherein said step c) comprises applying the high frequency voltage in the range of from about 20 volts RMS to about 90 volts RMS.  
     
     
         29 . The method of  claim 21 , wherein said step c) effects heating of the annulus fibrosus in a region adjacent to the active electrode to a temperature in the range of from about 45° C. to 50° C.  
     
     
         30 . The method of  claim 21 , wherein the active electrode is disposed on a distal end of a first shaft, and wherein said step b) 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.  
     
     
         31 . The method of  claim 30 , wherein the return electrode is disposed on a distal end of a second shaft, and the method further comprises: g) advancing the distal end of the second shaft to a location adjacent to an outer wall of the annulus fibrosus.  
     
     
         32 . The method of  claim 31 , wherein the return electrode is positioned external to the disc.  
     
     
         33 . A method for treating an intervertebral disc, comprising: 
 a) advancing an active electrode of an electrosurgical instrument from a location outside an intervertebral disc towards the annulus fibrosus; and    b) electrosurgically inactivating nervous tissue within the annulus fibrosus.    
     
     
         34 . The method of  claim 33 , wherein said step b) comprises inactivating nociceptors within the annulus fibrosus.  
     
     
         35 . The method of  claim 33 , wherein said step b) comprises applying a high frequency voltage between the active electrode and a return electrode, wherein the instrument is operating in a sub-ablation mode.  
     
     
         36 . The method of  claim 33 , wherein said step b) comprises coagulating nerve fibers within the annulus fibrosus.  
     
     
         37 . The method of  claim 36 , wherein said step b) comprises electrosurgically heating a posterior region of the annulus fibrosus to a temperature in the range of from about 45° C. to 50° C.  
     
     
         38 . A method for treating an intervertebral disc, comprising: 
 a) electrosurgically decompressing the disc; and    b) denervating the annulus fibrosus of the disc.    
     
     
         39 . The method of  claim 38 , wherein said step a) comprises electrosurgically ablating or shrinking a portion of the nucleus pulposus.  
     
     
         40 . The method of  claim 38 , wherein said step b) comprises electrosurgically heating a portion of the annulus fibrosus to a temperature sufficient to inactivate unmyelinated nerve fibers.  
     
     
         41 . The method of  claim 38 , wherein said step a) comprises introducing a first electrosurgical instrument within a nucleus pulposus of the disc, and said step b) comprises positioning a second electrosurgical instrument in at least close proximity to a posterior region of the annulus fibrosus.  
     
     
         42 . The method of  claim 38 , wherein said step b) comprises heating at least a portion of the annulus fibrosus to a temperature in the range of from about 45° C. to 50° C.  
     
     
         43 . A method for treating an intervertebral disc, comprising: 
 a) providing an electrosurgical instrument, the instrument including a shaft having a shaft distal end and an electrode assembly disposed at the shaft distal end, the electrode assembly including an active electrode and a return electrode;    b) positioning the active electrode within a nucleus pulposus of the disc;    c) electrosurgically decompressing the disc;    d) positioning the active electrode in at least close proximity to a posterior region of an annulus fibrosus of the disc; and thereafter    e) electrosurgically denervating the posterior region of the annulus fibrosus.    
     
     
         44 . The method of  claim 43 , wherein said step c) comprises applying a first high frequency voltage between the active electrode and the return electrode.  
     
     
         45 . The method of  claim 44 , wherein the first high frequency voltage effects ablation of at least a portion of the nucleus pulposus.  
     
     
         46 . The method of  claim 44 , wherein the first high frequency voltage effects shrinkage of at least a portion of the nucleus pulposus.  
     
     
         47 . The method of  claim 46 , wherein the first high frequency voltage effects heating of at least a portion of the nucleus pulposus to a temperature in the range of from about 60° C. to 70° C.  
     
     
         48 . The method of  claim 44 , further comprising the step of: 
 f) providing an electrically conductive fluid to the electrode assembly, wherein the electrically conductive fluid provides a current flow path between the active electrode and the return electrode.    
     
     
         49 . The method of  claim 48 , wherein the electrically conductive fluid comprises a gel.  
     
     
         50 . The method of  claim 43 , wherein said step e) comprises applying a second high frequency voltage between the active electrode and the return electrode.  
     
     
         51 . The method of  claim 50 , wherein the second high frequency voltage effects coagulation of unmyelinated nervous tissue within the annulus fibrosus.  
     
     
         52 . The method of  claim 50 , wherein the second high frequency voltage effects heating of the posterior region of the annulus fibrosus to a temperature in the range of from about 45° C. to 50° C., whereby nociceptors within the annulus fibrosus are inactivated.  
     
     
         53 . The method of  claim 52 , further comprising g) during said step e), monitoring a temperature of the annulus fibrosus in the vicinity of the shaft distal end.  
     
     
         54 . The method of  claim 50 , further comprising: 
 h) adjusting the second high frequency voltage in response to the temperature monitored in said step g).    
     
     
         55 . A method for treating back pain, comprising: 
 a) positioning an active electrode of an electrosurgical probe in at least close proximity to a target tissue of a patient's spine, wherein the target tissue comprises a region of a posterior longitudinal ligament; and    b) electrosurgically denervating the region of the posterior longitudinal ligament, whereby the back pain is alleviated.    
     
     
         56 . The method of  claim 55 , wherein said step b) comprises applying a high frequency voltage between the active electrode and a return electrode.  
     
     
         57 . The method of  claim 56 , wherein said step b) comprises applying the high frequency voltage in the range of from about 20 volts RMS to 90 volts RMS.  
     
     
         58 . The method of  claim 55 , wherein said step b) comprises electrosurgically heating the target tissue to a temperature sufficient to inactive unmyelinated nerve fibers within the target tissue.  
     
     
         59 . The method of  claim 58 , wherein the temperature is insufficient to cause contraction of collagen fibers within the target tissue.  
     
     
         60 . The method of  claim 58 , wherein the temperature is insufficient to cause shrinkage of the posterior longitudinal ligament.  
     
     
         61 . The method of  claim 55 , wherein said step b) comprises electrosurgically heating the target tissue to a temperature in the range of from about 43° C. to 53° C.  
     
     
         62 . The method of  claim 55 , wherein said step b) comprises electrosurgically heating the target tissue to a temperature in the range of from about 45° C. to 50° C.  
     
     
         63 . The method of  claim 55 , wherein said step b) comprises coagulating nervous tissue within the posterior longitudinal ligament.  
     
     
         64 . The method of  claim 55 , further comprising: 
 c) prior to said step a), introducing the probe into the patient endoscopically, percutaneously, or via an incision.    
     
     
         65 . The method of  claim 55 , wherein said step a) involves a laminotomy.  
     
     
         66 . A method for treating an intervertebral disc, comprising: 
 a) providing an apparatus adapted for the controlled heating of a target tissue;    b) via the apparatus, heating a posterior region of an annulus fibrosus of the disc; and    c) as a result of said step b), denervating at least a portion of the annulus fibrosus, whereby discogenic pain is alleviated, and wherein the apparatus does not contact or pass through a nucleus pulposus of the intervertebral disc.    
     
     
         67 . The method of  claim 66 , wherein said step b) comprises heating a portion of the disc to a temperature sufficient to inactivate unmyelinated nerve fibers but insufficient to contract collagen fibers of the annulus fibrosus.  
     
     
         68 . The method of  claim 66 , wherein said step b) comprises heating a portion of the disc to a temperature in the range of from about 43° C. to 53° C.  
     
     
         69 . A method for treating back pain, comprising: 
 a) providing an apparatus adapted for the controlled heating of a target tissue;    b) via the apparatus, applying heat to a region of the posterior longitudinal ligament; and    c) as a result of said step b), at least partially denervating the region of the posterior longitudinal ligament, whereby the back pain is alleviated.    
     
     
         70 . The method of  claim 69 , wherein said step b) effects heating of a portion of the posterior longitudinal ligament to a temperature in the range of from about 43° C. to 53° C.  
     
     
         71 . A method for treating back pain, comprising: 
 a) applying heat to a target tissue of a patient's spine;    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, whereby the pain is alleviated.    
     
     
         72 . The method of  claim 71 , wherein the at least a portion of the target tissue is exposed to a temperature in the range of from about 45° C. to 50° C.  
     
     
         73 . The method of  claim 71 , further comprising: 
 d) during said step a), sensing the temperature to which the target tissue is exposed;    e) comparing a sensed temperature value with a pre-set temperature value; and    f) adjusting the rate at which heat is supplied to the target tissue based on a comparison performed in said step e).    
     
     
         74 . The method of  claim 71 , wherein the heat is applied electrosurgically via an electrosurgical probe.  
     
     
         75 . The method of  claim 74 , wherein the probe does not contact, nor pass through, a nucleus pulpous of the disc.  
     
     
         76 . The method of  claim 74 , wherein the probe includes an active electrode disposed on a first shaft of the probe and a return electrode disposed on a second shaft of the probe, and the method further comprises: 
 g) advancing a working end of the first shaft through 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    h) advancing a working end of the second shaft towards the posterior of the annulus fibrosus such that the active electrode is positioned external to the annulus fibrosus at a second location adjacent to the posterior of the disc.    
     
     
         77 . A method for electrosurgically treating a target tissue, 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 with respect to the target tissue;    c) positioning the second electrode at a second location with respect to the target tissue; and    d) applying a high frequency voltage between the first electrode and the second electrode, wherein at least a portion of the target tissue is modified or ablated.    
     
     
         78 . The method of  claim 77 , wherein said step d) effects coagulation of the target tissue.  
     
     
         79 . The method of  claim 77 , wherein said step d) effects contraction of the target tissue.  
     
     
         80 . The method of  claim 77 , wherein said step d) effects denervation of the target tissue.  
     
     
         81 . The method of  claim 77 , wherein the second location is spaced from the first location by a distance in the range of from about 1 mm to 1 cm.  
     
     
         82 . The method of  claim 77 , wherein the first electrode is coupled to a first pole of a high frequency power supply, and the second electrode is coupled to a second pole of the high frequency power supply.  
     
     
         83 . The method of  claim 77 , wherein the first electrode comprises an active electrode, and the second electrode comprises a return electrode.  
     
     
         84 . The method of  claim 77 , wherein the target tissue comprises spinal tissue.  
     
     
         85 . The method of  claim 84 , wherein the target tissue comprises the annulus fibrosus of an intervertebral disc or the posterior longitudinal ligament.  
     
     
         86 . The method of  claim 85 , wherein said step d) effects heating of at least a portion of the target tissue to a temperature in the range of from about 45° C. to 50° C.  
     
     
         87 . The method of  claim 84 , wherein said step c) comprises positioning the second electrode at a location external to a posterior region of the annulus fibrosus, and wherein the posterior of the annulus fibrosus is at least partially denervated.  
     
     
         88 . An electrosurgical apparatus, comprising: 
 a first shaft having a first shaft distal end and a first shaft proximal end;    a first electrode disposed at the first shaft distal end;    a second shaft having a second shaft distal end and a second shaft proximal end;    a second electrode disposed at the second shaft distal end; and    a connection block for coupling the first electrode and the second electrode thereto.    
     
     
         89 . The apparatus of  claim 88 , wherein the connection block is adapted for coupling the first and second electrodes to a high frequency power supply.  
     
     
         90 . The apparatus of  claim 89 , further comprising a connection housing, wherein the first and second shafts are mechanically coupled to the connection housing.  
     
     
         91 . The apparatus of  claim 90 , wherein the first shaft and the second shaft are mechanically coupled to the connection housing via the first shaft proximal end and the second shaft proximal end, respectively.  
     
     
         92 . The apparatus of  claim 91 , wherein the connection block is housed within the connection housing.  
     
     
         93 . The apparatus of  claim 88 , further comprising a high frequency power supply, wherein the first and second electrodes are coupled to the high frequency power supply via the connection block.  
     
     
         94 . The apparatus of  claim 90 , wherein the first and second shafts extend in substantially the same direction from the connection housing.  
     
     
         95 . The apparatus of  claim 90 , wherein the first and second shafts are independently detachable from the connection housing.  
     
     
         96 . The apparatus of  claim 88 , wherein the first and second shafts are adapted for manipulation independently of each other.  
     
     
         97 . 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.    
     
     
         98 . The method of  claim 97 , wherein the second location is spaced from the first location by a distance in the range of from about 1 mm to 1 cm.  
     
     
         99 . The method of  claim 97 , wherein the second electrode is positioned external to the posterior of the disc.