Learning curve and complications of unilateral biportal endoscopy-unilateral laminectomy bilateral decompression for lumbar spinal stenosis.

Introduction: The unilateral biportal endoscopic (UBE) technique has been widely adopted for treat‑ ment of lumbar disc herniation and lumbar spinal stenosis. Understanding its learning curve, as well as the factors that influence perioperative complications, is crucial for mastering and effectively learning this technique.

Aim: Our aim was to analyze the learning curve of UBE‑unilateral laminectomy bilateral decompression (ULBD) and risk factors associated with perioperative complications.

Materials and methods: Consecutive patients who underwent UBE from June 2021 to December 2023 at the Department of Orthopedics, Beijing Friendship Hospital, were retrospectively analyzed. Baseline information, perioperative data, and preoperative and postoperative subjective scores were recorded for all patients. The learning curve and identified risk factors for complications were analyzed.

Results: A total of 122 consecutive patients who underwent single‑segment UBE‑ULBD were included in this study. The surgical time curve fitting indicated that the surgeon nearly mastered the technique by the 38th case. Consequently, the cohort was divided into 2 distinct phases: a learning phase (cases 1-38) and a mastery phase (cases 39-122). Operative time, estimated blood loss, and drainage volume were higher in the learning phase group than in the mastery phase group, although hidden blood loss in the learning phase group was lower than in the mastery phase group. The visual analogue scale and Oswestry Disability Index scores at the last follow‑up showed significant improvement in both groups as compared with the preoperative period (P <0.05). Complication rate was 7.9% in the learning phase and 3.6% in the mastery phase. Univariate analysis showed that age, body mass index, alcohol consumption, and estimated blood loss were significantly associated with complication rate.

Conclusions: UBE is an effective minimally‑invasive spinal endoscopic technique for treating lumbar spinal stenosis, offering short time to achieving surgical mastery and a low complication rate.