Comparison of clinical and radiological outcomes between microscope-assisted tubular unilateral laminectomy for bilateral decompression and bilateral laminotomy for crossover decompression in single-level lumbar spinal stenosis.

OBJECTIVE: To compare the clinical and radiological outcomes of microscope-assisted unilateral laminectomy for bilateral decompression (ULBD) and bilateral laminotomy for crossover decompression (BLCD) in the treatment of single-level lumbar spinal stenosis (LSS). METHODS: This retrospective comparative study included 65 patients with single-level LSS who underwent microscope-assisted tubular decompression between July 2023 and August 2024. Thirty-five patients underwent ULBD, and 30 underwent BLCD. The operative approach was selected in routine clinical practice without a predefined standardized anatomy-based allocation protocol. Baseline characteristics, operative time, and postoperative hospital stay were compared between the two groups. Clinical outcomes were assessed using visual analogue scale (VAS) scores for low back pain and leg pain and the Oswestry Disability Index (ODI) preoperatively and at postoperative follow-up time points. Radiological outcomes included changes in segmental lordosis and global lordosis, ipsilateral and contralateral facet joint preservation rates, postoperative dural sac cross-sectional area (DSCA), and DSCA change rate. RESULTS: Baseline demographic and clinical characteristics were comparable between the two groups. The ULBD group had a significantly shorter operative time than the BLCD group (105.3 ± 9.5 min vs.128.7 ± 11.3 min, P < 0.001), whereas postoperative hospital stay did not differ significantly. VAS scores for low back pain and leg pain and ODI scores improved significantly after surgery in both groups at all follow-up time points compared with baseline (P < 0.05), with no significant between-group differences. Changes in segmental lordosis and global lordosis were not significantly different between groups. The ipsilateral facet joint preservation rate was significantly lower in the ULBD group than in the BLCD group (67.55% ± 4.72% vs. 89.23% ± 7.89%, P < 0.001), while the contralateral preservation rate showed no significant difference. Postoperative DSCA and DSCA change rate were significantly greater in the BLCD group than in the ULBD group (P < 0.001). CONCLUSION: Both microscope-assisted ULBD and BLCD provide effective symptom relief and functional improvement in patients with single-level LSS. ULBD is associated with a shorter operative time, whereas BLCD provides better ipsilateral facet joint preservation and a greater radiological decompression effect. BLCD may therefore offer potential advantages in preserving posterior bony structures and achieving more extensive spinal canal decompression, while maintaining comparable short-term clinical efficacy.