Facet arthroplasty devices and methods

Abstract

A prosthesis system replaces facet joints on adjoining vertebral bodies. The prosthesis system employs a caudal prosthesis for fixation to a first vertebral body and a cephalad prosthesis for fixation to the second vertebral body. The caudal and cephalad prostheses have, respectively a first artificial caudal facet joint structure and an artificial cephalad facet joint structure, to replace all or a portion of, respectively a caudal and cephalad portions of the natural facet joint (i.e., superior and inferior articular processes, respectively) between the adjoining first and second vertebral bodies. The prosthesis system further employs a second artificial caudal facet joint structure fixed superior to the artificial cephalad facet joint structure on the second vertebral body. The second artificial caudal facet joint structure replaces all or a portion of a caudal portion of a natural facet joint (i.e., a superior articular process) between the second vertebral body and an adjoining third vertebral body superior to the second vertebral body.

1 - 49 . (canceled)  
     
     
         50 . A prosthesis system for replacing facet joints on adjoining vertebral bodies, comprising: 
 an implantable first facet joint structure configured for fixation to a first vertebral body at or near a pedicle without support by a lamina wherein the implantable first facet joint structure is configured to selectively replace the natural facet joint between the first vertebral body and an adjoining second vertebral body;    an implantable second facet joint structure configured for fixation to the second vertebral body at or near a pedicle without support by a lamina wherein the implantable second facet joint structure is configured to selectively replace the natural facet joint between the first vertebral body and an adjoining second vertebral body and form an articulating joint with the first implantable facet joint structure; and    an implantable third facet joint structure configured for fixation to a third vertebral body at or near a pedicle without support by a lamina wherein the implantable third facet joint structure is configured to selectively replace the natural facet joint between the third vertebral body and the first vertebral body or the natural facet joint between the third vertebral body and the second vertebral body.    
     
     
         51 . A prosthesis system according to  claim 50  wherein the implantable first facet joint structure, the implantable second facet joint structure or the implantable third facet joint structure is adapted and configured to replace at least some of a pedicle of the first vertebral body, the second vertebral body or the third vertebral body.  
     
     
         52 . A prosthesis system according to  claim 50  wherein at least one of the implantable first facet joint structure, the implantable second facet joint structure or the implantable third facet joint structure is made of at least one selected prosthetic material.  
     
     
         53 . A prosthesis system according to  claim 52  wherein the selected prosthetic material includes polyethylene, rubber, tantalum, titanium, chrome cobalt, surgical steel, bony in-growth material, ceramic, artificial bone, or a combination thereof.  
     
     
         54 . A prosthesis system according to  claim 50  wherein at least one of the implantable first facet joint structure, the implantable second facet joint structure or the implantable third facet joint structure includes a fastening element installed at or near the pedicle of the first vertebral body, the second vertebral body or the third vertebral body.  
     
     
         55 . A prosthesis system according to  claim 54  wherein the fastening element includes a screw.  
     
     
         56 . A prosthesis system according to  claim 54  wherein the fastening element includes means for resisting rotation.  
     
     
         57 . A prosthesis system according to  claim 55  wherein the fastening element includes a stem.  
     
     
         58 . A prosthesis system for replacing facet joints on adjoining vertebral bodies, comprising: 
 an implantable first facet joint structure configured for fixation to a first vertebral body at or near a pedicle without support by a lamina wherein the implantable first facet joint structure forms part of an articulating joint with a vertebral body adjoining the first vertebral body;    an implantable second facet joint structure configured for fixation to a second vertebral body at or near a pedicle without support by a lamina wherein the implantable second facet joint structure forms part of an articulating joint with a vertebral body adjoining the second vertebral body; and    an implantable third facet joint structure configured for fixation to a third vertebral body at or near a pedicle without support by a lamina wherein the implantable third facet joint structure forms part of an articulating joint with a vertebral body adjoining the third vertebral body.    
     
     
         59 . A prosthesis system according to  claim 58  further comprising an implantable fourth facet joint structure configured for fixation into a vertebral body adjoining the first vertebral body and forming part of an articulating joint with the implantable first facet joint structure.  
     
     
         60 . A prosthesis system according to  claim 58  further comprising an implantable fourth facet joint structure configured for fixation into a vertebral body adjoining the second vertebral body and forming part of an articulating joint with the implantable second facet joint structure.  
     
     
         61 . A prosthesis system according to  claim 58  further comprising an implantable fourth facet joint structure configured for fixation into a vertebral body adjoining the third vertebral body and forming part of an articulating joint with the implantable third facet joint structure.  
     
     
         62 . A prosthesis system for replacing facet joints on adjoining vertebral bodies, comprising: 
 an implantable first facet joint structure configured for fixation to a first vertebral body at or near a pedicle without support by a lamina wherein the implantable first facet joint structure is configured to selectively replace the natural facet joint between the first vertebral body and an adjoining second vertebral body;    an implantable second facet joint structure configured for fixation to the second vertebral body at or near a pedicle without support by a lamina wherein the implantable second facet joint structure is configured to selectively replace the natural facet joint between the first vertebral body and an adjoining second vertebral body and form an articulating joint with the first implantable facet joint structure; and    an implantable third facet joint structure configured for fixation to a third vertebral body at or near a pedicle without support by a lamina wherein the implantable third facet joint structure is configured to form part of an articulating joint with the first vertebral body or to form part of an articulating joint with the second vertebral body.    
     
     
         63 . A prosthesis system for replacing facet joints on adjoining vertebral bodies according to  claim 62  wherein the implantable third facet joint structure is configured to form part of an articulating joint with an artificial facet joint structure on the first vertebral body.  
     
     
         64 . A prosthesis system for replacing facet joints on adjoining vertebral bodies according to  claim 62  wherein the implantable third facet joint structure is configured to form part of an articulating joint with an artificial facet joint structure on the second vertebral body.  
     
     
         65 . A prosthesis system for replacing facet joints on adjoining vertebral bodies according to  claim 62  wherein at least one of the implantable first facet joint structure, the implantable second facet joint structure or the implantable third facet joint structure is made of at least one selected prosthetic material.  
     
     
         66 . A prosthesis system for replacing facet joints on adjoining vertebral bodies according to  claim 65  wherein the selected prosthetic material includes polyethylene, rubber, tantalum, titanium, chrome cobalt, surgical steel, bony in-growth material, ceramic, artificial bone, or a combination thereof.  
     
     
         67 . A prosthesis system for replacing facet joints on adjoining vertebral bodies according to  claim 62  wherein the implantable third facet joint structure is configured to form the caudal part of an articulating joint with an artificial facet joint structure on the first vertebral body.  
     
     
         68 . A prosthesis system for replacing facet joints on adjoining vertebral bodies according to  claim 62  wherein the implantable third facet joint structure is configured to form the cephalad part of an articulating joint with an artificial facet joint structure on the first vertebral body.  
     
     
         69 . A prosthesis system for replacing facet joints on adjoining vertebral bodies according to  claim 62  wherein the implantable third facet joint structure is configured to form the caudal part of an articulating joint with an artificial facet