Clinical Outcomes of Selective Single-Level Lumbar Endoscopic Unilateral Laminotomy for Bilateral Decompression of Multilevel Lumbar Spinal Stenosis and Risk Factors of Reoperation

Study Design: Retrospective cohort study. Objectives: To investigate the usefulness of selective single-level lumbar endoscopic unilateral laminotomy for bilateral decompression (LE-ULBD) in patients with radiological multilevel lumbar spinal stenosis (LSS) and clarify the predictive factors of reoperation. Methods: A total of 128 patients who underwent LE-ULBD of radiological multilevel LSS were retrospectively examined. Single-level decompression was selected clinically and supplemented radiologically. Clinical outcomes were assessed with the Japanese Orthopaedic Association Back Pain Evaluation Questionnaire (JOABPEQ), numeric rating scale (NRS), and Macnab criteria (mean follow-up period, 28.6 months [range, 24-63 months]). Stenosis severity was classified as grades M (moderate) and S (severe) based magnetic resonance imaging findings. Multilevel LSS was classified as SS, SM, and MM according to the number of grade S levels. Results: The follow-up rate was 74.2%. All domains of the JOABPEQ and NRS significantly improved during follow-up. The Macnab outcome classification was "excellent" or "good" in 77.9% of the patients. The reoperation rate was 10.2%. None of the patients with unilateral symptoms required reoperation. The SS type was a significant risk factor of reoperation for multilevel LSS with bilateral symptoms. Additional LE-ULBD was performed for all the reoperation with the "excellent" or "good" results of the Macnab criteria in 69% of the patients. Conclusions: Selective single-level LE-ULBD provided favorable results for multilevel LSS. However, information about the risks of reoperation for multilevel severe stenosis with bilateral symptoms should be shared between surgeons and patients.