Abstract
STUDY DESIGN: A retrospective observational study. PURPOSE: To assess the clinical and radiological outcomes of unilateral laminotomy for bilateral decompression (ULBD) using biportal endoscopic spinal surgery (BESS) in patients with low-grade degenerative lumbar spondylolisthesis (DLS) and central canal stenosis. OVERVIEW OF LITERATURE: DLS with central canal stenosis frequently requires surgical intervention to alleviate symptoms. Although traditional fusion surgeries are effective, they are associated with risks such as adjacent segment disease and increased postoperative morbidity. BESS presents a minimally invasive alternative that aims to achieve adequate decompression while preserving segmental stability. METHODS: A total of 68 patients with symptomatic, low-grade DLS and moderate-to-severe central canal stenosis underwent ULBD using BESS. Patients were followed for at least 2 years. Clinical outcomes were measured using the Visual Analog Scale (VAS) for back and leg pain, the Oswestry Disability Index (ODI), and the modified Macnab criteria for patient satisfaction. Radiological outcomes were assessed on the basis of sagittal translation from dynamic flexion-extension radiographs. RESULTS: The mean VAS score for back pain decreased from 3.8±2.4 preoperatively to 1.9±2.0 at the final follow-up, and the leg pain scores decreased from 6.4±1.8 to 2.3±2.0 (both p<0.05). The ODI score improved significantly from 48.9±15.7 preoperatively to 23.1±17.5 at the final follow-up (p<0.05). According to the modified Macnab criteria, 27.9%, 42.6%, 22.1%, and 7.4% of the patients reported excellent, good, fair, and poor outcomes. Radiological assessments indicated no significant changes in sagittal translation, supporting the preservation of spinal stability. CONCLUSIONS: BESS with ULBD represents a safe and effective minimally invasive approach for treating low-grade DLS with central canal stenosis. It offers substantial symptom relief and functional improvement without jeopardizing spinal stability, making it a viable alternative to conventional fusion surgery.