Comparison of early outcomes of unilateral biportal endoscopic decompression and microscopic unilateral laminotomy for bilateral decompression in lumbar spinal stenosis

Aims: Unilateral biportal endoscopic (UBE) decompression is increasingly used for lumbar spinal stenosis.However, comparative evidence against microscopic unilateral laminotomy for bilateral decompression (ULBD) outside East Asian populations remains limited.This study aimed to compare the short-term clinical and perioperative outcomes of UBE and microscopic ULBD.Methods: This retrospective two-center study included adults with single-level degenerative lumbar spinal stenosis (Schizas grade B or higher) treated with UBE at one center or microscopic ULBD at another and followed for at least six months.Patients with multilevel disease, high-grade spondylolisthesis, or prior index-level surgery were excluded.Co-primary endpoints were hemoglobin decrease and time to first mobilization.The two groups were compared, with Bonferroni-adjusted significance set at p<0.025.Results: Of 102 patients (mean age 65.6±7.1 years; 52.9% female), 46 underwent UBE and 56 ULBD, with comparable baseline characteristics (all p>0.05).UBE yielded less hemoglobin decrease (0.46±0.14 vs. 1.06±0.20 g/dL; p<0.001), and earlier mobilization (3.93±1.10 vs. 12.73±2.70hours; p<0.001).Operative time was longer with UBE (57.00±4.59 vs. 45.05±4.53minutes; p<0.001),and hospital stay was shorter (1.59±0.49vs. 1.96±0.63days; p=0.003).At six months, back visual analog scale (VAS) favored UBE (2.15±0.91 vs. 2.89±0.92;p<0.001), whereas leg VAS (1.71±0.80 vs. 1.78±0.54;p=0.157) and Oswestry disability index (16.24±3.14 vs. 17.18±3.38;p=0.153) were comparable.Dural injury (4.3% vs. 10.7%;p=0.289) and wound discharge (2.2% vs. 5.4%; p=0.625) did not differ.Conclusions: Both techniques improved short-term outcomes.UBE was associated with smaller hemoglobin decrease, earlier mobilization, shorter hospitalization, and lower VAS scores for back pain, with comparable functional outcomes and complications at six months.