A Prospective, Observational, Open-Label, Nonrandomized, Multicenter Study Measuring Functional Outcomes in a Novel Interspinous Stabilization Device in Patients With Low Back Pain: 12-Month Results for the REFINE Study.

BACKGROUND

Lumbar spinal stenosis associated with degenerative disc disease is a common source of pain and reduced quality of life in older adults. Current focus has centered on minimally invasive options. Previous reports of the performance of a novel standalone interlaminar fixation device have been previously reported. This cohort represents the 12-month outcomes, looking at safety and efficacy.

METHODS

Ninety-four patients underwent implantation, and 79 completed follow-ups. The primary endpoint was a composite clinical success, incorporating the absence of index-level revision or reoperation, clinically meaningful improvement in pain using the visual analog scale, disability improvement as measured by the Oswestry Disability Index, and better disease-specific status as measured by the Zurich Claudication Questionnaire. Secondary outcomes included changes in PROMIS-29 and Patient Global Impression of Change. Safety assessment included adverse events, readmissions, and reoperations. Analyses used the implanted cohort with paired comparisons for follow-up data and interpretation using prespecified minimal clinically important difference thresholds.

RESULTS

Patients demonstrated statistically significant improvement in disability, pain, and disease-specific function. Mean Oswestry Disability Index improved by 22.0 points; back and leg pain visual analog scale score improved by 35.7 and 36.5 points, respectively. Zurich Claudication Questionnaire symptom severity and physical function also improved, and PROMIS-29 domains were favorable across pain interference, sleep disturbance, fatigue, anxiety, depression, social roles, and physicality. Patient Global Impression of Change responses indicated 83% of patients reported at least minimal improvement. Six adverse events were reported, 3 of which were deemed related to the device or procedure. No index-level reoperations, device explants, or symptomatic spinous process fractures were reported.

CONCLUSIONS

In this prospective multicenter cohort, standalone interlaminar fixation produced clinically meaningful improvement in pain, disability, and patient-reported quality of life.

CLINICAL RELEVANCE: This study represents the first prospectively acquired data for a posterior interspinous fixation device used without other instrumentation to treat systematic spinal stenosis in the presence of degenerative disc disease.

LEVEL OF EVIDENCE: Level 2: prospective, nonrandomized, multicenter trial.