Lumbar Facet Resurfacing: First Experience With the FENIX™ Implant.

STUDY DESIGN: This is a feasibility study to confirm the design, the patient population and the surgical technique for FENIX™ implants.

OBJECTIVE: This study evaluated the safety, the clinical and radiological performance of bilaterally implanted FENIX™ facet resurfacing device.

INTRODUCTION: Facet joint osteoarthritis is responsible for up to 30% of chronic low back pain. Arthroplasty is a surgical treatment option that aims to relieve pain while maintaining or restoring motion.

METHODS: Eight consecutive patients with proven single segmental bilateral lumbar facet-joint osteoarthritis as unique pain generator received a bilateral implantation of the FENIX ™ device. Correct device placement and mobility preservation were assessed by X-ray, 6 weeks, 6, 12 and 24 months after implantation. MRI at 12 and 24 months post-surgery assessed the bony ingrowth and CT-SPECT was repeated at 6 months to assess evolution of the pre-operative inflamed facet joints. Oswestry Disability Index, the pain Visual Analogue Scale and need for analgesic medication were the parameters used for clinical assessment.

RESULTS: Seven of the eight patients had all implants in place, 24 months after surgery and all assessed parameters were normal. Patients experienced significant pain relief and functionality improvement. Mobility was maintained and no Mobic changes were noted at the index nor at the adjacent levels. No 'hot' lesions at the implanted levels were observed on CT-SPECT. One of the 48 (2%) implants was dislocated at 6 months follow-up.

CONCLUSION: The FENIX ™ facet resurfacing technique might be considered in the future as surgical treatment of well selected patients suffering from chronic low back pain due to facet joint osteoarthritis. A modification of the superior implant should provide an initial firm fixation preventing implant dislocation.