Implantable device for facet joint replacement

Abstract

Cephalad and caudal vertebral facet joint prostheses and methods of use are provided. The prostheses provide an artificial facet joint structure including an artificial articular configuration unlike the preexisting articular configuration. The radii and material stress values of the prostheses are configured to sustain contact stress. The cephalad prosthesis provides for posterior-anterior adjustment. Both prostheses permit lateral adjustment and adjustment to accomodate interpedicle distance. Further, the prostheses may be customized to provide a pre-defined lordotic angle and a pre-defined pedicle entry angle.

1 - 55 . (canceled)  
   
   
       56 . An implantable device for facet joint replacement comprising: 
 a component sized to be fixed to a first vertebral body and including a joint structure adapted to replace a portion of a natural facet joint and articulate with a second vertebral body.    
   
   
       57 . An implantable device according to  claim 56  further comprising a fixation element sized to accommodate adjustment of the component relative to the first vertebral body.  
   
   
       58 . An implantable device according to  claim 56  wherein the joint structure comprises a generally convex articulating surface.  
   
   
       59 . An implantable device according to  claim 56  wherein the joint structure comprises a generally concave articulating surface.  
   
   
       60 . An implantable device according to  claim 56  wherein the joint structure comprises a biocompatible polymer.  
   
   
       61 . An implantable device according to  claim 56  wherein the joint structure comprises a surface adapted to articulate with a facet structure of a second vertebral body.  
   
   
       62 . An implantable device according to  claim 56  wherein the joint structure comprises a surface adapted to articulate with an artificial structure on a second vertebral body.  
   
   
       63 . An implantable device according to  claim 56  wherein the joint structure is adapted to replace a cephalad portion of the facet joint.  
   
   
       64 . An implantable device according to  claim 56  wherein the joint structure is adapted to replace a caudal portion of the facet joint.  
   
   
       65 . An implantable device according to  claim 56  wherein the joint structure is adapted to replace a caudal portion and a cephalad portion of the facet joint.  
   
   
       66 . An implantable device according to  claim 56  further comprising a fixation element, wherein a fixation region on the fixation element is configured and arranged to support the fixation element at a desired entry angle.  
   
   
       67 . An implantable device according to  claim 56  further comprising a fixation element, the device further comprising a fixation region on the fixation element that is configured and arranged to support the fixation element at an angle that approximates a desired lordotic angle.  
   
   
       68 . An implantable device according to  claim 56  further comprising a first fixation region configured and arranged to fix the component to the first vertebral body at or near a pedicle.  
   
   
       69 . An implantable device according to  claim 56  further comprising a first fixation region configured and arranged to fix the component to the first vertebral body at or near a lamina.  
   
   
       70 . An implantable device according to  claim 56  further comprising a first fixation region configured and arranged to fix the component to the first vertebral body at or near a spinous process.  
   
   
       71 . An implantable device according to  claim 56  further comprising a first fixation region configured and arranged to fix the component to the first vertebral body at or near a spinous process.  
   
   
       72 . A method of replacing, on a vertebral body, a portion of a natural facet joint using the implantable device as defined in  claim 56 , the method comprising the steps of (i) removing at least a portion of the natural facet joint from the vertebral body, and (ii) fixing the implantable device as defined in claim  1  to the vertebral body to replade the removed portion of the natural facet joint with the joint structure.  
   
   
       73 . A device for replacing a portion of a facet joint between adjacent vertebral bodies, the device comprising: 
 a component sized to be fixed to a first vertebral body and including a structure adapted to replace the portion of a facet joint, thereby allowing the first vertebral body to articulate with a second vertebral body.    
   
   
       74 . An implantable device according to  claim 73  further comprising a fixation element sized to accommodate adjustment of the component relative to the first vertebral body.  
   
   
       75 . An implantable device according to  claim 73  wherein the structure comprises a biocompatible polymer.  
   
   
       76 . An implantable device according to  claim 73  wherein the structure comprises a surface adapted to articulate with a facet structure of the second vertebral body.  
   
   
       77 . An implantable device according to  claim 73  wherein the structure comprises a surface adapted to articulate with an artificial structure attached to a second vertebral body.  
   
   
       78 . An implantable device according to  claim 73  wherein the structure is adapted to replace a cephalad portion of the facet joint.  
   
   
       79 . An implantable device according to  claim 73  wherein the structure is adapted to replace a caudal portion of the facet joint.  
   
   
       80 . An implantable device according to  claim 73  wherein the structure is adapted to replace a caudal portion and a cephalad portion of the facet joint.  
   
   
       81 . An implantable device according to  claim 73  further comprising a fixation element, wherein a fixation region on the fixation element is configured and arranged to support the fixation element at a desired entry angle.  
   
   
       82 . An implantable device according to  claim 73  further comprising a first fixation region configured and arranged to fix the component to the first vertebral body at or near a pedicle.  
   
   
       83 . An implantable device according to  claim 73  further comprising a first fixation region configured and arranged to fix the component to the first vertebral body at or near a lamina.  
   
   
       84 . An implantable device according to  claim 73  further comprising a first fixation region configured and arranged to fix the component to the first vertebral body at or near a spinous process.