Mobility-Maintaining Facet Arthroplasty of the Lumbar Spine With the Second-Generation TOPS System: A Case Series

Lumbar spinal stenosis results from spinal canal narrowing and can lead to pain and dysfunction. Until recently, surgical treatment for lumbar spinal stenosis requiring an extensive decompression, with or without spondylolisthesis, had to balance pain relief with the long-term risks of spinal instability after decompression and adjacent segment disease (ASD) after spinal fusion. Spinal motion-preserving devices aim to reduce the incidence of ASD after posterolateral fusion and consequent need for revision surgery. OBJECTIVE: To present a single-center experience with a facet replacement implant (TOPS System [TOtal Posterior Spine System], Premia Spine) designed to stabilize the spine and prevent further degeneration while maintaining a normal range of motion (ROM). METHODS: Seventeen patients received the implant after a laminotomy. Clinical assessments included surgery duration, complication rates, and visual analog score for back pain. Radiographs were used to measure ROM changes from flexion to extension and assess for any repositioning of a degenerative spondylolisthesis and segment lordosis. RESULTS: The average operative time was 102 minutes. The average visual analog score reduction was 7.5 at 3 months, 6.8 at 12 months, and 6.7 at the longest follow-up (average: 51 months, range: 26-77), demonstrating an average improvement of 81%. The preoperative and postoperative average ROMs were 8.2° and 7.4°, respectively. CONCLUSION: This series shows that the TOPS System has the potential to relieve back pain and maintain close-to-normal ROM over longer time periods without inducing ASD. The TOPS System is the first to allow the patient to settle into physiological lordosis adjustment thus presenting new treatment possibilities with mobility-maintaining dorsal instrumentation.