Implant device used in minimally invasive facet joint hemi-arthroplasty

Abstract

A metallic inverted L-shaped implant is used to resurface the superior facet of the inferior vertebrae limited to the facet joints located on the spine, Occiput-C1 through L5-S1. The metallic implant is highly polished on its exterior and textured on its interior surface. It is mechanically crimped in place without the use of cement or pedicle screws. Permanent fixation occurs when bone in-grows onto a rough, porous surface on the inside of the implant. The implant employed in a hemi-arthroplasty method resurfaces half of the facet joint to provide for smooth, pain free joint articulation in deteriorated or diseased spinal facet joints without the need for major surgery or rehabilitation at considerably less risk to the patient.

1 - 17 . (canceled) 
   
   
       18 . A prosthetic implant for use in minimally invasive facet joint hemi-arthroplasty, the implant comprising:
 an inverted L-shaped a metallic body comprising a convex top portion integral at a rear edge with a concave downwardly descending portion, the top and downwardly descending portions having a highly polished exterior surface of a material biocompatible with bone;   a concave lower surface under the top portion and convex inner textured surface on the downwardly descending portion; and   at least one blade integral with the convex inner textured surface and a pair of teeth descending from a front edge of the convex top portion, wherein the at least one blade is positioned and configured to provide lateral stability when the implant is inserted into the facet joint and wherein the pair of teeth provides temporary fixation of the implant into the bone when the implant is inserted.   
   
   
       19 . The implant of  claim 18  wherein the highly polished exterior surface of the implant is a cobalt-chrome alloy. 
   
   
       20 . The implant of  claim 18  wherein the highly polished exterior surface of the implant is a titanium alloy. 
   
   
       21 . The implant of  claim 18  wherein the convex inner textured surface of the implant is porous and compatible with bone. 
   
   
       22 . The implant of  claim 18  further comprising two blades integral with the convex inner textured surface, wherein the two blades are positioned and configured to provide lateral stability when the implant is inserted into the facet joint. 
   
   
       23 . The implant of  claim 18  further configured to be mounted within the facet joint such that the highly polished exterior surface is juxtaposed to oppositely positioned bones in the facet joint. 
   
   
       24 . The implant of  claim 18  further configured to be mounted within the facet joint such that the textured surface conforms to the shape of a juxtaposed bone. 
   
   
       25 . The implant of  claim 22  further configured to be mounted within a facet joint such that the textured surface conforms to the shape of a juxtaposed bone and the two blades cut into the juxtaposed bone, and wherein the two blades are positioned and configured to provide lateral stability when the implant is inserted into the facet joint. 
   
   
       26 . The implant of  claim 18  further configured to be crimped into place in the facet joint. 
   
   
       27 . The implant of  claim 26  wherein the pair of teeth are configured to be pressed to downwardly into the bone to crimp the implant into place. 
   
   
       28 . The implant of  claim 26  further configured to be crimped into place using an impactor to impact the implant into place in the facet joint. 
   
   
       29 . The implant of  claim 26  further configured to be crimped into place without the use of screws or cement. 
   
   
       30 . An apparatus for performing minimally-invasive facet joint arthroplasty, comprising:
 an inverted L-shaped prosthetic implant comprising:
 a metallic body having a convex top portion integral at a rear edge with a concave downwardly descending portion, the top and downwardly descending portions having a highly polished exterior surface of a material biocompatible with bone; 
 a concave lower surface under the top portion and convex inner textured surface on the downwardly descending portion; and 
 at least one blade integral with the convex inner textured surface and 
 a pair of teeth descending from a front edge of the convex top portion; 
   the implant configured to be mounted within the facet joint such that the highly polished exterior surface is juxtaposed to oppositely positioned bones in the facet joint and such that the textured surface conforms to the shape of a juxtaposed bone, wherein the at least one blade is positioned and configured to provide lateral stability when the implant is inserted into the facet joint and wherein the pair of teeth provides temporary fixation of the implant into the bone when the implant is inserted into the facet joint; and   the implant further configured to be crimped into place in the facet joint.   
   
   
       31 . The apparatus of  claim 30  wherein the highly polished exterior surface of the implant is a cobalt-chrome alloy. 
   
   
       32 . The apparatus of  claim 30  wherein the highly polished exterior surface of the implant is a titanium alloy. 
   
   
       33 . The apparatus of  claim 30  wherein the convex inner textured surface of the implant is porous and compatible with bone.