May 13, 2006 - Investigators conducting a clinical study on the outcome of patients receiving the TFAS® Total Facet Arthroplasty System (a patented facet replacement used as an alternative to laminectomy and fusion in the treatment of spinal stenosis) presented their findings at the 6th Annual Meeting of the Spine Arthroplasty Society in Montreal Canada on May 13th, 2006.  Dr. Scott Webb and his colleagues collected data on patients followed up to one year and found that the patients’ neurogenic claudication symptoms were alleviated, post-operative function improved, and the biomechanics of their affected levels were restored.

“This data begins to establish the safety and effectiveness of total joint arthroplasty in the posterior column of the spine, which beyond stabilizing the spine post decompression surgery, effectively restores stability and natural kinematics after excision of the facets and posterior ligamentous structures to a level similar to that of an intact spine.” said Scott Webb, DO, of the Florida Spine Institute, Clearwater, Florida.

Webb and his colleagues prospectively followed the first 13 patients who received the TFAS® implant.  All patients were assessed at six months postoperatively with two patients being assessed out a full year from receiving the implant.

The study population consisted of 13 subjects (8 Male/ 5 Female) of an average age of 60.7 years. Patients had degenerative disease of the facets and up to a Grade I degenerative spondylolisthesis with objective evidence of neurologic impairment, along with central or lateral spinal stenosis.  Four subjects were treated at L3-L4 and nine were treated at L4-L5. No operative adverse events were reported.  One patient was lost to follow-up due to a non-device related death.  The TFAS® device was verified to be intact radiographically. In all cases the TFAS® was well fixed, properly aligned, and functional with correct sizing and placement.

The investigators recorded and presented pre and post operative Zurich Claudication Questionnaire (ZCQ) function and symptom scores as well as Visual Analog Scale (VAS) leg and back pain scores. Webb and colleagues documented a significant increase in function and decrease in pain and sympton scores, which were sustained for all patients at all time points.  Additionally, the mechanical back pain that is usually associated with post-decompression fusion was not seen in these patients.  According to Dr. Webb, “This is preliminary information, but could be significant if this trend continues as the sample population grows.”

The investigators found that the average ZCQ symptom scores and ZCQ function scores improved by an average of 50.2% and 46.0% respectively. VAS leg and VAS back pain scores improved by an average of 78.2% and 63.1% respectively.

Webb said, “Traditionally, patients that are fused after a decompression have been associated with a higher risk of adjacent level disease. This early experience is encouraging as noted by the overall improvement noted in ZCQ and VAS measures. The promise of physiological load sharing and biomechanical restoration of facet movement may pay a significant role in decreasing adjacent level disease.  The TFAS® system has accommodated all anatomic variability, and the instrumentation has allowed for accurate, predictable implantation of the device. Hopefully long term follow-up will show significant benefits from facet joint replacement, both at the operative and adjacent levels.