Prone Endoscopic Lateral Lumbar Interbody Fusion: Operative Technique and Functional Outcomes in 35 Patients

Background Lateral lumbar interbody fusion is a widely used technique to address degenerative lumbar conditions but can be associated with injury to the psoas, lumbar plexus, and abdominal wall owing to retractor usage. We describe a minimally invasive endoscopic lateral lumbar interbody fusion (ELLIF) procedure that aims to reduce these complications by avoiding prolonged muscle retraction, preparing the disc space under direct endoscopic vision, and shortening the surgical time. Methods Between 2019 and 2024, 35 patients underwent ELLIF at a single center. Discectomy, endplate preparation, and iliac crest harvest were done via a working-channel endoscope without expandable retractors. Neurophysiological monitoring was used to minimize nerve injury. Outcomes included complications, visual analog scale scores for pain, and Oswestry Disability Index (ODI). Results Of the 35 patients (mean age 60 years), 26 had preoperative radicular pain and 9 had neurological deficits. Six minor complications occurred in 4 patients (11.4%), all managed conservatively without permanent deficits. No patients developed new radiculopathy or paresis, and there were no infections or reoperations. ODI improved by 57% at 1 month and by 88% at 1 year (both P < 0.001). By the 3-year follow-up in 9 patients, ODI scores remained near normal, and visual analog scale was reduced by 93% from baseline. Clinical Relevance We present a minimally invasive, ELLIF, and decompression technique that provides patients with minimal complications and excellent functional recovery. Conclusion ELLIF offers a safe, minimally invasive alternative for patients with lumbar degenerative disease. This technique minimizes direct retraction on the psoas and lumbar plexus, resulting in a low complication rate and substantial functional recovery at short- and medium-term follow-up. Level of Evidence 4.