Consecutive Case Series of Uniportal Full-endoscopic Unilateral Laminotomy for Bilateral Decompression in Lumbar Spinal Stenosis: Relationship between Decompression Range and Functional Outcomes.

Abstract

Uniportal full-endoscopic unilateral laminotomy for bilateral decompression (UFE-ULBD) has been used to treat lumbar spinal stenosis (LSS) with satisfactory outcomes. However, a limited number of studies have investigated the relationship between decompression range and clinical outcomes. This study aimed to investigate the efficacy of UFE-ULBD for single-segment LSS and to explore the relationship between the decompression range and functional outcomes. Single-segment LSS patients who had undergone UFE-ULBD using an interlaminar approach between November 2021 and February 2023 were retrospectively analyzed. Patient demographics, visual analogue scale (VAS) scores for leg and back pain, Oswestry disability index (ODI) scores, modified MacNab grades, and radiological outcomes, including the decompression ratio of the disc-flava ligament space and osseous lateral recess, the enlargement ratio of superior articular process interval, lamina interval dural sac cross-sectional area (DSCA), were collected. The independent sample t-tests, paired sample t-tests, chi-square tests, Fisher's exact tests, and Pearson's and Spearman's correlation analyses were used. Forty patients (23 males, and 17 females) were retrospectively enrolled in this study. The mean follow-up period was 12 months. At the last follow-up, VAS scores for leg pain and back pain decreased from 6.0 ± 0.8 to 1.0 ± 1.9 (p < 0.001), and from 6.0 ± 0.8 to 1.2 ± 1.8 (p < 0.001) respectively; ODI score decreased from 71.7 ± 6.2 to 24.3 ± 21.3 (p < 0.001). According to the modified MacNab criteria, the results were excellent in 28 (70%), good in 5 (12.5%), fair in 6 (15%), and poor in 1 (2.5%), with an excellent-good rate of 82.5%. The postoperative DSCA enlarged from 57.69 ± 21.86 to 150.75 ± 39.33 mm2 (p < 0.001), with an enlargement ratio of 189.43 ± 107.83%. No difference in clinical or radiological parameters was detected between patients with excellent, good, fair, or poor outcomes based on the modified MacNab criteria. UFE-ULBD can provide satisfactory clinical and radiological outcomes in single-segment LSS patients. With sufficient exposure to the dural sac boundary, the functional outcome was not related to the radiological decompression range in LSS patients who had undergone UFE-ULBD.