Perioperative Complications of Oblique Lateral Interbody Fusion With Unilateral Pedicle Screw Fixation in a Single Lateral Position: A Retrospective Case Series

Study Design Retrospective case series. Objectives To analyze the perioperative complications of oblique lateral interbody fusion (OLIF) combined with unilateral pedicle screw fixation performed in a single lateral position. Methods Clinical data of 258 consecutive patients with lumbar degenerative diseases undergoing OLIF-UPS fixation in a single lateral position from July 2019 to June 2025 were collected. Both single- and multi-segment fusions were included. Demographic, intraoperative and perioperative data were extracted for statistical analysis. Results Among the 258 patients, the overall perioperative complication rate was 17.1%. Neurological deficits (6.2%) and pedicle screw insertion-related complications (5.4%) were the most common. Other complications included endplate injury (3.5%), cage malposition (2.7%), poor incision healing (1.9%), anterior longitudinal ligament injury (1.6%), vascular injury (1.6%), cage subsidence (1.2%), intestinal obstruction (1.2%), and peritoneal injury (0.4%). The complication rate was higher in the Multi-level fusion group than in the single-level group (21.9% vs. 15.5%, P=0.237). The incidences of neurological deficits (7.8% vs. 5.7%, P=0.538) and screw-related complications (7.8% vs. 4.6%, P=0.331) were also higher in the Multi-level group; however, none of these differences reached statistical significance. Conclusions The overall perioperative complication rate in this cohort was 17.1%, and the perioperative complications were manageable. Further controlled studies with long-term follow-up are needed to compare its efficiency and safety with alternative fixation protocols and positioning strategies.