Minimally invasive facet joint hemi-arthroplasty

Abstract

A minimally invasive facet joint hemi-arthroplasty method using a unique metallic overlay, instrumentation and surgical protocol to resurface the superior facet of the inferior vertebrae limited to the facet joints located on the lumbar spine, Occiput-C1 through L5-S1. Using related new instrumentation and a surgical protocol invented to prepare the joint, a metallic overlay 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. This 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. This procedure may also be used to prophylactically resurface the joint to minimize or eliminate future deterioration caused by the additional stress to facet joints from disc replacements or instrumented vertebral fusion. Instrumentation includes a newly invented planer, director probe with slap-hammer, vertebral separator, osteotome, broach, crimper and facet joint prosthetic implant for use in surgically resurfacing facet joints located from Occiput-C1 through L5-S1 using a minimally invasive outpatient facet joint hemi-arthroplasty method developed specifically for that purpose.

1 . A metallic overlay constructed of cobalt-chrome or any other biocompatible metal or metallic alloy presenting a smooth, polished surface on its outside allowing for virtually frictionless joint articulation and rough or porous construction on its inside that is amenable to natural bone in growth to provide a permanent fixation. Said inlay is generally shaped to fit the natural contour of the facet joint and sized to fit any or all of the forty-eight facet joints located vertebral segments Occuput-C1 through L5-S1.  
   
   
       2 . The Device of  claim 1  has a porous inner surface made of the same material as the device.  
   
   
       3 . The Device of  claim 1  has a porous inner surface made of a different material as the device.  
   
   
       4 . The Device of  claim 1  wherein said component contains one or more fins on its inner portion to provide lateral fixation.  
   
   
       5 . The Device of  claim 1  wherein said component contains one or more teeth that may be crimped into the cortical bone to prevent migration of the Device.  
   
   
       6 . The Device if  claim 1  wherein said component is constructed of a non-metallic, non-degradable biocompatible material presenting the same durability as its metallic version.