Instrumented Facet Fusion in the Lumbosacral Spine: Long-Term Clinical and Radiographic Results

Surgical treatments for degenerative lumbar spinal disorders involve decompression of neural structures and arthrodesis to address pain from unstable intervertebral segments. Lumbar instrumented facet fusion (IFF), a less invasive technique, has shown positive short-term outcomes, but reports on its long-term outcomes are scarce. This study aims to report its long-term biomechanical stability and clinical outcomes.

This single-center retrospective observational case series included patients who underwent single- or two-level IFF for degenerative lumbar spinal disorders from January 1996 to January 2021. Patient demographics, Oswestry Disability Index and visual analog scale scores, and radiographic fusion were assessed using flexion-extension radiographs and CT scans. Instrument failures and fusion segment angles were measured.

A total of 494 patients underwent IFF during the studied period. Of those, 208 were followed up for more than 24 months (mean follow-up of 89.96 ± 55.59 months). The overall fusion rate was 92.05%. Revision surgery due to adjacent segmental disease was done in 11.06% of patients. Screw loosening was observed in 6 patients, of whom 2 underwent revision surgery. Significant improvements in Oswestry Disability Index and visual analog scale were observed.

IFF is a safe and less invasive alternative method of lumbar spinal arthrodesis with a comparable fusion rate and clinical outcome. This method shows a relatively low revision rate.