Clinical outcomes of uni-portal non-coaxial spinal endoscopic surgery versus unilateral biportal endoscopic surgery for lumbar spinal stenosis: a retrospective cohort study

Objective To compare the clinical efficacy and safety of uni-portal non-coaxial spinal endoscopic surgery (UNSES) with unilateral biportal endoscopic technique (UBE) for the treatment of lumbar spinal stenosis (LSS). Methods We retrospectively analyzed 195 patients with LSS (96 in the UNSES group and 99 in the UBE group) from January 2022 to December 2023. The two groups were compared regarding operative time, postoperative hemoglobin decrease, incision length, length of hospital stay, complication rate, functional scores (VAS, JOA, ODI), and imaging parameters, including dural sac cross-sectional area (DCSA), lumbar range of motion (ROM), and sagittal translation (ST). Results No significant differences were observed in baseline characteristics between the UNSES and UBE groups. Compared with the UBE group, the UNSES group showed shorter operative time (65.2 ± 8.1 vs. 72.5 ± 9.3 min, P < 0.001), lower hemoglobin decrease (6.2 ± 1.4 vs. 6.8 ± 2.5 g/L, P = 0.039), a smaller incision length (1.8 ± 0.3 vs. 2.5 ± 0.4 cm, P < 0.001), and fewer fluoroscopy exposures (3.1 ± 1.2 vs. 4.5 ± 2.0, P < 0.001). Both groups showed postoperative improvement in pain, functional scores, and DCSA compared with preoperative values ( P < 0.05), whereas ROM and ST remained unchanged. No intergroup differences were observed in these parameters or in complication rates at any time point (all P > 0.05). Conclusion At the 1-year follow-up, UNSES and UBE were associated with comparable clinical and radiographic outcomes in patients with single-segment lumbar spinal stenosis. Compared with UBE, UNSES was associated with differences in several perioperative parameters, including operative time, hemoglobin decrease, incision length, and fluoroscopy exposure. These findings should be interpreted with caution, given the retrospective design and limited follow-up duration.