Lumbar Endoscopic Unilateral Laminotomy for Bilateral Decompression for Lumbar Spinal Stenosis Provides Comparable Clinical Outcomes in Patients with and without Degenerative Spondylolisthesis

OBJECTIVE: To investigate and compare the clinical and radiological outcomes of lumbar endoscopic unilateral laminotomy for bilateral decompression (LE-ULBD) for lumbar spinal stenosis (LSS) patients with and without degenerative spondylolisthesis (DS). METHODS: A total of 129 patients who underwent LE-ULBD for single-level LSS were retrospectively reviewed. The patients were classified into 2 groups based on the presence of DS. Clinical outcomes were assessed with the Japanese Orthopaedic Association Back Pain Evaluation Questionnaire and numeric rating scale (NRS) for low back pain, lower limb pain, and lower limb numbness. Scores were obtained at baseline and final follow-up (mean follow-up, 28.6 months [range, 24-63 months]). RESULTS: The follow-up rate was 77.5% (103 patients). All domains of the Japanese Orthopaedic Association Back Pain Evaluation Questionnaire and NRS evaluations significantly improved during the follow-up period in both groups; group differences were not significant except for the postoperative NRS limb numbness score, which was higher in patients with DS. The Macnab outcome classification was excellent or good in 80% of patients without DS and 77.1% of patients with DS. During the follow-up period, the increase of vertebral slip was observed in 31% of the patients with DS that includes vertebral slip progression defined as percent slip >5% in 4% of the patients. The increase of vertebral slip was not related to a clinical outcome. Segmental motion of the affected intervertebral disc did not increase after surgery. CONCLUSIONS: LE-ULBD provides a comparably favorable outcome in LSS patients with and without DS. Postoperative segmental instability did not occur in patients with DS.