Prosthetic facet and facet joint replacement device

Abstract

Spinal stabilization devices, systems, and methods are described. Foramenal spacers including a rigid member adapted to maintain the integrity of the foramenal space. Facet joint stabilizing members and prosthetic facet joints that augment or replace the native facet joint are also described. Lateral spinal stabilization systems that may be attached to the lateral surfaces of adjacent vertebral bodies are described. Also described are anterior spinal stabilization systems that are to be attached to the anterior surfaces of adjacent vertebral bodies. Several variations of dynamic spinal stabilization devices and systems are described. Each of the foregoing devices, systems, and methods may be used independently, in combination with the other devices, systems, and methods described herein, and/or in combination with prosthetic intervertebral discs.

We claim as our invention: 
     
         1 . A facet stabilizing member having a size and shape suitable for placement in a spinal facet joint and to provide stabilization to the facet joint comprising:
 a.) a core member comprising a polymeric material for providing shock absorbing and spacing in the facet joint, and   b.) a woven jacket encasing the core member, selected to maintain the shape of the core member.   
     
     
         2 . The facet stabilizing member of  claim 1  where the polymeric material of the core member is selected from hydrogel and urethane. 
     
     
         3 . The facet stabilizing member of  claim 1  where the jacket is a woven fabric. 
     
     
         4 . A facet stabilizing member having a size and shape suitable for placement in a spinal facet joint and to provide stabilization to the facet joint comprising:
 a. an upper end plate with a fixation member configured to be fixed to a facet,   b. a lower end plate with a fixation member configured to be fixed to a facet, and   c. a core member extending between and interconnecting the upper and lower end plates comprising a polymeric material for providing shock absorbing and spacing in the facet joint and further comprising fibers wound between the upper and lower end plates.   
     
     
         5 . The facet stabilizing member of  claim 4  where the polymeric material of the core member is selected from hydrogel and urethane. 
     
     
         6 . An inter-spinous process, dynamic stabilizing device interposable between spinous processes associated with a first vertebral body with a first spinous process and a second vertebral body with a second spinous process, the second vertebral member being adjacent said first vertebral body, said device comprising:
 a. upper and lower spinous process attachment members for attachment, respectively, to the first spinous process and to the second spinous process, and   b. two spring members, each spring member extending between, attached to, and lateral of both of the upper and lower spinous process attachment members.   
     
     
         7 . The inter-spinous process, dynamic stabilizing device of  claim 6  wherein the upper and lower spinous process attachment members are U-shaped to accept first and second spinous process members. 
     
     
         8 . The inter-spinous process, dynamic stabilizing device of  claim 7  wherein the upper and lower spinous process attachment members further comprise screws to secure the upper and lower spinous process attachment members to the first and second spinous process members. 
     
     
         9 . The inter-spinous process, dynamic stabilizing device of  claim 6  wherein the spring members comprise a shape-memory alloy. 
     
     
         10 . The inter-spinous process, dynamic stabilizing device of  claim 6  wherein the spring members comprise nitinol. 
     
     
         11 . The inter-spinous process, dynamic stabilizing device of  claim 10  wherein the spring members comprise a nitinol alloy chosen to allow adjustment of spring shapes, spring size, or performance characteristic upon application of heat to the spring members. 
     
     
         12 . A dynamic stabilizing system interposable between an upper vertebral body and a lower vertebral body, the lower vertebral body being adjacent said first vertebral body, said system comprising:
 a. a posterior stabilization device attachable both to the posterior of the upper vertebral body and to the posterior of the lower vertebral body, and comprising one or more members selected from springs and dampers, and   b. an anterior stabilization device attachable both to the anterior of the upper vertebral body and to the anterior of the lower vertebral body, and comprising a member constrainable by rolling or folding for implantation onto the anterior of the upper vertebral body and onto the anterior of the lower vertebral body and further, upon release of the constraint, for attachment to the anterior of the upper vertebral body and to the anterior of the lower vertebral body.   
     
     
         13 . The dynamic stabilizing device of  claim 12  wherein the posterior stabilization device is attached both to the posterior of the upper vertebral body and to the posterior of the lower vertebral body. 
     
     
         14 . The dynamic stabilizing device of  claim 12  wherein the anterior stabilization device is attached both to the anterior of the upper vertebral body and to the anterior of the lower vertebral body. 
     
     
         15 . The dynamic stabilizing device of  claim 12  further comprising bone screws for attaching the posterior stabilization device both to the posterior of the upper vertebral body and to the posterior of the lower vertebral body and for attaching the anterior stabilization device both to the anterior of the upper vertebral body and to the anterior of the lower vertebral body. 
     
     
         16 . A dynamic stabilizing system interposable between an upper vertebral body with upper transverse processes and a lower vertebral body with lower transverse processes, the lower vertebral member being adjacent the upper vertebral body, the system comprising:
 a. two inter-transverse process stabilization members each extendable between and attachable to an upper transverse process and a lower transverse process, and   b. upper and lower bone screws for attaching the two inter-transverse process stabilization members to the upper transverse process and to the lower transverse process.   
     
     
         17 . The dynamic stabilizing system of  claim 16  where each of the inter-transverse process stabilization members comprises one or more members selected from springs and dampers.