[Short-term effectiveness of unilateral biportal endoscopy technique in treatment of lumbar lateral saphenous fossa combined with intervertebral foramina stenosis via contralateral sublaminar approach].

Objective: To investigate the short-term effectiveness of unilateral biportal endoscopy (UBE) in treatment of lumbar lateral saphenous fossa combined with intervertebral foramina stenosis via contralateral sublaminar approach.

Methods: A clinical data of 15 patients with lumbar lateral saphenous fossa combined with intervertebral foramina stenosis, who were admitted between September 2021 and December 2023 and met selective criteria, was retrospectively analyzed. There were 5 males and 10 females with an average age of 70.3 years (range, 46-83 years). Surgical segment was L _{4, 5} in 12 cases and L ₅, S ₁ in 3 cases. The disease duration was 12-30 months (mean, 18.7 months). All patients were treated by UBE via contralateral sublaminar approach. The operation time, intraoperative blood loss, postoperative hospital stay, and the occurrence of complications were recorded. The visual analogue scale (VAS) score was used to evaluate the degree of lower back and leg pain before and after operation; the Japanese Orthopaedic Association (JOA) score and the Oswestry disability index (ODI) were used to evaluate the lumbar function; and the clinical outcome was evaluated using the MacNab criteria at 6 months after operation. Postoperative MRI and CT were taken to observe whether the lateral saphenous fossa and intervertebral foramen stenosis were removed or not, and the cross-sectional area of the spinal canal (CSA-SC), cross-sectional area of the intervertebral foramen (CSA-IVF), and cross-sectional area of the facet joint (CSA-FJ) were measured.

Results: The operation time was 55-200 minutes (mean, 127.5 minutes); the intraoperative blood loss was 10-50 mL (mean, 27.3 mL); the length of postoperative hospital stay was 3-12 days (mean, 6.8 days). All patients were followed up 6-12 months (mean, 8.9 months). At 1 day, 1 month, 3 months, and 6 months after operation, the VAS scores of low back and leg pain and ODI scores after operation were significantly lower than preoperative scores and showed a gradual decrease with time; the JOA scores showed a gradual increase with time; the differences in the above indexes between different time points were significant ( P<0.05). The clinical outcome was rated as excellent in 10 cases, good in 4 cases, and poor in 1 case according to the MacNab criteria at 6 months after operation, with an excellent and good rate of 93.33%. Imaging review showed that the compression on the lateral saphenous fossa and intervertebral foramina had been significantly relieved, and the affected articular process joint was preserved to the maximum extent; the CSA-SC and CSA-IVF at 3 days after operation significantly increased compared to the preoperative values ( P<0.05), and the CSA-FJ significantly reduced ( P<0.05).

Conclusion: The UBE via contralateral sublaminar approach can effectively reduce pressure in the lateral saphenous fossa and the intervertebral foramina of the same segment while preserving the bilateral articular process joints. The short-term effectiveness is good and it is expected to avoid fusion surgery caused by iatrogenic instability of the lumbar spine. However, further follow-up is needed to clarify the mid- and long-term effectiveness.