Comparative efficacy of uniportal and biportal endoscopic decompression within 3 decompression boundaries for degenerative lumbar spinal stenosis: a retrospective cohort study

To compare the clinical and radiological outcomes of uniportal endoscopic unilateral laminotomy for bilateral decompression (UE-ULBD) versus biportal endoscopic unilateral laminotomy for bilateral decompression (BE-ULBD) within 3 predefined decompression boundaries for degenerative lumbar spinal stenosis (DLSS).

This study adopted a retrospective cohort study design. Medical records of DLSS patients who underwent UE-ULBD or BE-ULBD at the Department of Orthopedics, Daping Hospital, Army Medical University from January 2022 to October 2023 were collected. After applying inclusion and exclusion criteria, 69 patients who completed follow-up and had complete medical records were enrolled and divided into 2 groups according to surgical approach: the UE-ULBD group (n=34) and the BE-ULBD group (n=35). All patients had more than 6 months of follow-up, with a mean followup duration of (9.84±2.25) months. Three decompression boundaries were strictly followed intraoperatively. Clinical outcomes were assessed using VAS and ODI; operative time was also recorded. Radiological outcomes were evaluated by measuring the dural sac cross-sectional area, multifidus cross-sectional area, medial facet angle, facet joint width, and articular surface length on imaging.

No statistically significant differences were found between the two groups in demographic parameters including age, sex, disease duration, surgical approach side, and surgical segment. ODI and VAS scores improved significantly in both groups compared with preoperative values (P<0.05). The BE-ULBD group had a shorter operative time than the UE-ULBD group (P<0.001), whereas the latter showed significantly less postoperative paraspinal multifidus swelling (15.41±7.20 vs 111.3±26.08 mm², P<0.001). No statistically significant differences were observed between the two groups in dural sac expansion area (90.29±16.07 vs 92.83±11.93 mm², P=0.459), bilateral medial facet angle increase (ipsilateral: 40.82±4.41 vs 41.47±4.19°, P=0.529; contralateral: 16.96±6.81 vs 18.18±5.05°, P=0.401), facet joint articular surface length resection range (ipsilateral: 2.17±1.06 vs 2.64±1.01 mm, P=0.061; contralateral: 1.38±0.64 vs 1.41±0.77 mm, P=0.838), or facet joint width resection range (ipsilateral: 1.98±1.02 mm vs 1.87±1.01 mm, P=0.678; contralateral: 2.02±1.07 vs 2.07±0.66 mm, P=0.833).

When three decompression boundaries are strictly adhered to intraoperatively, both UE-ULBD and BE-ULBD can achieve equivalent radiological decompression effects and similar facet joint resection rates, with both yielding good clinical outcomes. BE-ULBD offers higher surgical efficiency, whereas UE-ULBD causes less paraspinal soft tissue damage.