gms | German Medical Science

Objective: Surgical decompression is extremely effective at relieving pain symptoms due to lumbar spinal stenosis. Decompression with interlaminar stabilization (D+ILS) is as effective as decompression with posterolateral fusion for stenosis, as shown in a US FDA pivotal trial. This study reports a multi-center, randomized controlled trial comparing D+ILS to decompression alone (DA) for treatment of moderate to severe lumbar spinal stenosis.

Methods: Under approved institutional ethics review, six sites in Germany treated 230 patients (1:1 ratio) randomized to either DA or D+ILS (Coflex, Paradigm Spine, New York, NY). Patients had moderate to severe lumbar spinal stenosis at one or two adjacent segments from L3 to L5. Outcomes were evaluated up to two years postoperatively, including Oswestry disability index (ODI), presence of secondary surgery or lumbar injections, neurologic status, and the presence of device or procedure-related severe adverse events. Composite clinical success (CCS) was defined as combining all four of these outcomes, a success-definition validated in a US FDA pivotal trial. Additional secondary endpoints included visual analog scales, Zurich claudication questionnaire, narcotic usage, walking distance, and radiographs.

Results: The follow-up rate was 91% at 2 years. There were no significant differences in patient-reported outcomes (PROs) at 24 months (p > 0.05). The CCS was superior for D+ILS (p = 0.017). The risk of secondary intervention was 1.75 times higher among DA patients compared to D+ILS patients (p = 0.055). The DA arm had 228% more lumbar injections (P=0.0065) compared to D+ILS. DA patients had a numerically higher rate of narcotic use at every time point post-surgically (16.7% D+ILS vs. 23% DA at 24 month). Walking distance test results were statistically significantly different from baseline where D+ILS had greater than 5 times improvement compared to only a 2 times improvement for DA from baseline. Foraminal height and disc height was largely maintained in D+ILS patients, while DA patients showed a significant decrease at 24 months postoperative (p<0.001).

Conclusion: Our study showed no significant difference in the individual PROs between the treatments when viewed in isolation. The CCS is statistically superior for interlaminar stabilization. D+ILS increases walking distance, decreases compensatory pain management, and maintains foraminal height extending the durability and sustainability of a decompression procedure.