Coflex Interspinous Stabilization with Decompression for Lumbar Spinal Stenosis: An Average 14-Year Follow-Up

Background: This study aimed to evaluate the long-term clinical usefulness and radiologic changes around the Coflex device following decompression with Coflex insertion for degenerative lumbar spinal stenosis (DLSS), with an average follow-up of 14 years. Methods: This retrospective study included 147 patients who underwent decompression and Coflex insertion for single-level DLSS at a single institution between January 2007 and December 2010. Patients with spinal stenosis unresponsive to 3 months of conservative treatment were treated surgically. The mean follow-up duration was 173.9 ± 23.7 (range, 119–214) months. Results: The mean visual analog scale score decreased from 8.22 ± 1.06 preoperatively to 2.08 ± 1.58 postoperatively. Intervertebral disc height and foramen height at the Coflex insertion site decreased by 5.3% and 2.0%, respectively, after surgery. The reoperation rate at the operated site was 25% (n = 37). A significantly higher reoperation rate was observed in patients with translational instability (odds ratio [OR], 7.77; 95% confidence interval [CI], 2.453–24.658; p < 0.01) and angular instability (OR, 1.59; 95% CI, 0.492–5.133; p < 0.001). Eight patients underwent reoperation due to rapid progression of instability within 2 years of Coflex insertion; thereafter, a similar cumulative incidence rate was consistently observed. The adjacent-segment reoperation rate was 10.8% (n = 16). Conclusions: The Coflex interspinous device helps preserve disc and foramen height but is associated with a high reoperation rate, particularly in patients with spinal instability. Therefore, careful patient selection is crucial when considering its use.