Unilateral biportal endoscopy-unilateral laminectomy bilateral decompression for lumbar spinal stenosis: Imaging parameters and clinical outcomes
Authors: Li Dongyue , Tao Luming , Zhang Xinuo , Su Qingjun 
Published: August 2024

Background:Unilateral biportal endoscopy-unilateral laminectomy bilateral decompression (UBE-ULBD) has been increasingly performed for the treatment of lumbar spinal stenosis (LSS). However, few researchers have investigated the relationship between the imaging parameters and clinical outcomes following UBE-ULBD. This study aimed to report the imaging parameters and clinical outcomes following UBE-ULBDin LSS patients and their possible relationship.
Method: From July 2020 to December 2022, 46 LSS patients who received UBE-ULBD were retrospectively analyzed. Two patients were operated at the L3/4 segment, 27 patients at the L4/5 segment, and 17 patients at the L5/S1 segment. The operation time, intraoperative blood loss, and associated complications were recorded. The patients were assessed before surgery, at 1 month after surgery, and upon the last follow-up using the visual analog scale (VAS) for leg and lower back pain. The clinical outcomes of patients were assessed by using the Oswestry Disability Index (ODI) and the modified Macnab criteria. Imaging parameters were recorded, including the angle of the medial surface of facetectomy (MSF), residual rate of the facet joint (FJ), decompression rate of the lateral recess (LR), increase in the dural sac cross-sectional area (DSCA), and motion range of the operated lumbar segment.
Result: Surgeries were performed on 46 patients. The average operation time was 93.59±13.73 min, and the average follow-up was 24.54±6.71 months. The preoperative VAS score for lower back pain was 5.87±0.94. At 1 month after surgery and at the last follow-up, the VAS score for lower back pain decreased to 2.30±0.66 and 0.61±0.54, respectively (P<0.05). The preoperative VAS score for leg pain was 6.78±0.89. At 1 month after surgery and at the last follow-up, the VAS score for leg pain decreased to 1.67±0.60 and 0.50±0.59, respectively (P<0.05). The preoperative ODI was 64.48±7.47. At 1 month after surgery and at the last follow-up, ODI decreased to 26.09±2.80 and 10.96±2.30, respectively (P<0.05). According to the modified MacNab criteria during the last follow-up, the results were excellent in 33 (71.7%), good in 8 (17.4%), fair in 5 (10.9%), with the excellent and good rate of 89.1%. As for the radiological evaluation, the average angle of MSF after surgery was below 90°, and the average residual rate of FJ was above 70%. There was no significant difference in the motion range of the operated segment before and after surgery (P>0.05). The average increase in DSCA was 95.19±22.54% (P<0.05). However, there were no significant differences in the imaging parameters between patients achieving excellent and good outcomes and those achieving fair and poor outcomes according to the modified MacNab criteria (P>0.05).
Conclusion: UBE-ULBDachieved satisfactory clinical and imaging outcomes in LSS patients, resulting in a desired increase in DSCA. Postoperative stability of lumbar facet joints was effectively preserved by this procedure, which further ensured lumbar spine stability. There was no significant correlation between the imaging parameters and the improvement of clinical outcomes.