Case Report on Contralateral Neural Complications following OLIF

Oblique Lumbar Interbody Fusion (OLIF) is widely used minimally invasive techniques for lumbar degenerative diseases. While neurological complications are recognized, they predominantly affect the ipsilateral lumbar plexus. Contralateral L4 nerve root compression is an exceptionally rare and often overlooked complication, with limited understanding of its biomechanical mechanisms and sparse radiological evidence linking symptoms to specific causes. A 61-year-old female underwent L3/4 and L4/5 OLIF via a left retroperitoneal approach for degenerative spondylolisthesis and spinal stenosis. Postoperatively, she developed right lower extremity pain and quadriceps weakness. Imaging revealed a malpositioned interbody cage and a fractured L4 osteophyte fragment compressing the contralateral L4 nerve root. Revision surgery via a transforaminal lumbar interbody fusion (TLIF) approach successfully removed the fragment and decompressed the nerve, leading to complete symptom resolution at 5-month follow-up. This case provides direct radiological and intraoperative confirmation of contralateral L4 nerve root compression due to cage malposition and osteophyte fracture-a rarely documented mechanism. Contributing factors likely included asymmetric cage placement and potential patient positioning inaccuracies. The report underscores the importance of precise surgical techniques, including rigorous fluoroscopic verification, optimal patient positioning, and consideration of intraoperative navigation to prevent such complications. Prompt postoperative imaging and timely intervention are crucial for managing unexpected neurological deficits. This case demonstrates that timely revision surgery successfully resolved the contralateral neurological deficits, resulting in complete functional recovery at 5-month follow-up. Enhanced awareness and adherence to preventive strategies can significantly reduce the incidence of this serious, yet preventable, complication in lateral access lumbar surgery.