Background Unilateral biportal endoscopy (UBE)-assisted transforaminal lumbar interbody fusion (TLIF) is an evolving minimally invasive option for lumbar instability. We evaluated outcomes of a lateralized, extra-flaval UBE-TLIF technique that preserves the ligamentum flavum and leverages anatomic/vascular landmarks within Kambin’s triangle. Methods Retrospective series of 58 consecutive cases (single surgeon, January 2024 to January 2025). All procedures were performed under general endotracheal anesthesia with local portal-site infiltration. Interbody preparation and cage insertion were performed through a lateralized extra-flaval corridor under biplanar fluoroscopy with percutaneous pedicle screw–rod fixation in all cases without navigation and intraoperative neuromonitoring. The primary outcomes analysis evaluated Oswestry Disability Index and visual analog scale (VAS) back and leg pain scores preoperatively and at 2 weeks, 1 month, 6 months, and 1 year. Paired t tests assessed within-patient change. Results In the analyzed cohort (n = 58), Oswestry Disability Index improved from 83.28 ± 7.31 preoperatively to 41.48 ± 10.16 (2 weeks), 17.73 ± 5.91 (1 month), 11.17 ± 3.71 (6 months), and 6.31 ± 3.72 (1 year; all P P Conclusion Extra-flaval, lateralized UBE-TLIF with percutaneous pedicle screw fixation, performed under general anesthesia with local infiltration and guided by fluoroscopy without navigation or neuromonitoring, yielded rapid, durable improvements in disability and pain at 12 months with a low complication rate. Flavum preservation and precise corridor definition may enhance neural safety and facilitate large-cage insertion. Prospective studies with standardized fusion assessment are warranted. Clinical Relevance This study provides evidence that endoscope-assisted UBE lumbar TLIF offers significant and sustained improvements in functional disability and pain scores, supporting its use as a minimally invasive treatment option for symptomatic lumbar spondylolisthesis. Level of Evidence 5.
Pestonji et al. (2026) studied this question.