Background: Traditional surgical options for the treatment of symptomatic lumbar spinal stenosis include decompression alone vs decompression and fusion; both options have potential limitations.

Objective: To report the 36-month follow-up analysis of the coflex Interlaminar Stabilization (Paradigm Spine, LLC, New York, New York) after decompression, examined under a Food and Drug Administration investigational device exemption clinical trial, which is intended to provide stabilization after decompression while preserving normal segmental motion at the treated level.

Methods: The coflex trial was a prospective, randomized investigational device exemption study conducted at 21 clinical sites in the United States. Baseline and follow-up visits collected demographics, clinical, and radiographic status. The primary endpoint was a measure of composite clinical success 24 months postoperatively. For this current 36-month analysis, composite clinical success was calculated using analogous methods.

Results: Composite clinical success at 36 months was achieved by 62.2% among 196 coflex Interlaminar Stabilization patients and 48.9% among 94 fusion patients (difference = 13.3%, 95% confidence interval, 1.1%-25.5%, P = .03). Bayesian posterior probabilities for noninferiority (margin = -10%) and superiority of cofle Interlaminar Stabilization vs fusion were >0.999 and 0.984, respectively. Substantial and comparable improvements were observed in both groups for patient-reported outcomes, although the percentage with a clinically significant improvement (≥15) in the Oswestry Disability Index seemed larger for the coflex Interlaminar Stabilization group relative to the fusion group (P = .008). Radiographic measurements maintained index level and adjacent level range of motion in coflex Interlaminar Stabilization patients, although range of motion at the level superior to fusion was significantly increased (P = .005).

Coflex Interlaminar Stabilization for stenosis is proven to be effective and durable at improving overall composite clinical success without altering normal spinal kinematic motion at the index level of decompression or adjacent levels.

Abbreviations: CCS, composite clinical successCEC, clinical events committeeFDA, Food and Drug AdministrationIDE, investigational device exemptionILS, Coflex Interlaminar StabilizationODI, Oswestry Disability IndexSF-12, Short-Form 12VAS, visual analogue scalesZCQ, Zurich Claudication Questionnaire.