Comparison of biportal endoscopic technique and uniportal endoscopic technique in Unilateral Laminectomy for Bilateral Decomprssion (ULBD) for lumbar spinal stenosis.

Objective: Unilateral laminotomy for bilateral decompression (ULBD) has been adopted widely to treat lumbar spinal stenosis (LSS). The objective of the study is to investigate clinical and radiological outcomes of the biportal endoscopic ULBD (BE-ULBD) and uniportal endoscopic ULBD (UE-ULBD).

Methods: We collected retrospectively 65 patients' data who met the inclusion criteria (July 2019-June 2021). 33 patients underwent BE-ULBD surgery, and 32 patients underwent the UE-ULBD surgery, and were followed up for at least 1 year. The following preoperative and postoperative outcomes were compared between groups: the visual analog scale (VAS) for pain, the Oswestry disability index (ODI) for nerve function, and modified Macnab criteria for satisfaction, the cross-sectional area of the dural sac (DSCSA), the mean angle of facetectomy.

Results: Age, BMI, gender, levels of involvement and duration of symptoms were not significantly different at baseline in this study. Clinical data showed that postoperative ODI, VAS scores and Modified Macnab Criteria were not statistically different between the two groups. The BE-ULBD group had a shorter operation time than the UE-ULBD group (P < 0.001). Patients in the BE-ULBD group had a larger postoperative expansion of DSCSA expansion postoperatively (85.58 ± 3.16 mm VS 71.43 ± 3.35 mm, P < 0.001) and a larger contralateral facetectomy angle (63.95 ± 3.34° vs 57.80 ± 3.43°, P < 0.001) compared with patients in the UE-ULBD group. There were no statistical differences in the incidence of postoperative complications between the two groups.

Conclusion: Both the BE-ULBD and the UE-ULBD yielded clinical improvement in terms of pain and stenosis symptoms. The BE-ULBD technique has the advantages of the shorter operation time, larger DSCSA expansion and larger contralateral facetectomy angle.