Posterior dynamic stabilization of spine

Abstract

The present invention provides various interspinous vertebral implants and methods for using the same for dynamic stabilization of a spine. The interspinous vertebral implants of the present invention comprise a resiliently compressible body that is adapted for position between adjacent superior and inferior spinous processes, and an anchoring member that is affixed to the superior and the inferior spinous processes posterior to the resiliently compressible body. The anchoring member provides a compressive force while the resiliently compressible body provides a distraction. Without being bound by any theory, it is believed that the combination of the distraction and compressive forces created by interspinous vertebral implants of the present invention result in a rotational moment, which alleviates compression on the intervertebral disk.

1 . A method of stabilizing adjacent superior and inferior vertebrae, each vertebra including a spinous process, the method comprising:
 placing an interspinous vertebral implant between the spinous process of the superior vertebra and the spinous process of the inferior vertebra such that the interspinous vertebral implant simultaneously exerts a compressive force on posterior portions of the superior and inferior spinous processes while exerting opposing distraction forces on anterior portions of the superior and inferior spinous processes.   
     
     
         2 . The method of  claim 1 , wherein the interspinous vertebral implant includes a distraction member positioned between the superior and inferior spinous processes exerting the opposing distraction forces. 
     
     
         3 . The method of  claim 2 , wherein the interspinous vertebral implant includes a first anchoring member secured to the superior spinous process and a second anchoring member secured to the inferior spinous process. 
     
     
         4 . The method of  claim 3 , wherein the first anchoring member is secured to the superior spinous process posterior of the distraction member. 
     
     
         5 . The method of  claim 4 , wherein the second anchoring member is secured to the inferior spinous process posterior of the distraction member. 
     
     
         6 . The method of  claim 5 , wherein the interspinous vertebral implant provides a rotational moment to the superior and inferior spinous processes relatively posterior to the distracting member. 
     
     
         7 . The method of  claim 5 , wherein the first and second anchoring members are joined by a spring portion. 
     
     
         8 . The method of  claim 2 , wherein the distraction member is a compressible body contacting surfaces of each of the superior and inferior spinous processes. 
     
     
         9 . The method of  claim 1 , wherein the combination of the distraction and compressive forces results in a reduction of compressive forces on an intervertebral disk between the superior and inferior vertebrae. 
     
     
         10 . The method of  claim 1 , wherein simultaneously exerting a compressive force on posterior portions of the superior and inferior spinous processes while exerting opposing distraction forces on anterior portions of the superior and inferior spinous processes restores a normal curvature between the superior and inferior vertebrae. 
     
     
         11 . A method of dynamically stabilizing adjacent superior and inferior vertebrae, each vertebra including a spinous process, the method comprising:
 applying a distraction force to the spinous processes of the superior and inferior vertebrae by placing a compressible body between the spinous processes, wherein the compressible body contacts a surface of each of the spinous processes; and   simultaneously providing a rotational moment to the superior and inferior spinous processes at a location posterior to the compressible body, thereby reducing the amount of compressive force on an intervertebral disk between the superior and inferior vertebrae.   
     
     
         12 . The method of  claim 11 , wherein the rotational moment is provided by securing first and second anchoring members to the superior and the inferior spinous processes, respectively, posterior to the compressible body. 
     
     
         13 . The method of  claim 12 , wherein the first and second anchoring members exert a compressive force on posterior portions of the superior and inferior spinous processes. 
     
     
         14 . The method of  claim 12 , wherein the first and second anchoring members are joined by a spring portion. 
     
     
         15 . The method of  claim 14 , wherein the spring portion is at least partially enclosed in the compressible body. 
     
     
         16 . The method of  claim 15 , wherein the compressible body comprises an elastomeric material. 
     
     
         17 . The method of  claim 11 , wherein providing a rotational moment restores a normal curvature between the superior and inferior vertebrae.