Contralateral Nerve Root Injuries after Oblique Lumbar Interbody Fusion: Causes, Treatment, and Prevention.

OBJECTIVE: Oblique lumbar interbody fusion (OLIF) is a minimally invasive technique used to treat degenerative spinal diseases. Although the common complications of OLIF have been well-documented, there is limited research on contralateral root injuries and few comprehensive reviews in the existing literature. This study analyzed the causes, treatment methods, and prevention strategies for contralateral root injuries based on our clinical experience. METHODS: We retrospectively reviewed 1011 OLIF procedures performed at our hospital between April 2018 and November 2024. Patients who underwent OLIF using the anterior to psoas (ATP) approach and developed significant postoperative contralateral nerve root symptoms attributable to OLIF were included. Patients with symptoms attributable to other causes or other confounding conditions were excluded. RESULTS: We identified nine cases (0.9%) of contralateral nerve root injuries. The primary causes were cage malposition (three cases), remnant disc rupture (four cases), and facet synovial rupture (two cases). Such injuries are often associated with severe postoperative pain and motor deficits. In cases of cage malposition, it is crucial to maintain the cage within safe intraoperative margins. Remnant disc ruptures are unpredictable and challenging to diagnose even with postoperative magnetic resonance imaging. Facet synovial rupture is a previously unreported complication that occurs in patients with significant facet hypertrophy and subluxation. CONCLUSION: Although rare, contralateral root injuries can cause severe neurological damage requiring reoperation. Our findings on the three mechanisms of contralateral root injury after OLIF, along with treatment and prevention strategies, provide valuable clinical insights into safer OLIF procedures.