Lumbar Plexus Injury after MIS Lateral Transpsoas Interbody Fusion at L4/5 Level: A Review of 62 Consecutive Cases

Presented at SMISS Annual Forum 2016
By Jacob Januszewski
With Juan Uribe MD, FACS, Andrew Vivas MD, Jason Paluzzi , Konrad Bach , Po Chun ,

Disclosures: Jacob Januszewski None Juan Uribe MD, FACS A; Nuvasive. B; Nuvasive. C; Nuvasive. D; Nuvasive. F; Nuvasive, Andrew Vivas MD None, Jason Paluzzi None, Konrad Bach None, Po Chun None,


The MIS lateral transpsoas approach (MIS-LIF) has become an increasingly popular means of fusion. Its most frequent complication is lumbar plexus injury. Reported complication rates at the L4/5 disc space vary widely in the literature, bringing into question the safety of MIS-LIF for the L4/5 region. Single level complication rates have been rarely reported alone. 


We report our experience with lumbar plexus injuries, safety, and efficacy of MIS-LIF at the L4/5 disc space. 


A retrospective analysis of our MIS-LIF database was performed over a period of approximately 5 years from October 2011 to April 2016. Inclusion criteria were any patient with a standalone or supplemental lateral plate or posterior percutaneous pedicle screw MIS-LIF at the L4/5 level. Exclusion criteria included any patient with a multi level fusion. We analyzed lumbar plexus injuries (sensory and/or motor), and the date of resolution. 


A total of 62 patients out of 303 matched our inclusion criteria. Twelve of these patients (19%) had an immediate postoperative complication, and almost all were transient and sensory in nature. One patient had a delayed contralateral sensory and motor (2/5) femoral nerve injury from psoas heatoma. All patient complications except for 2 have completely resolved by the 12-month follow up resulting in long-term complication rate of 3.2%. The mean hospital stay and follow-up were 2.1 days and 15 months, respectively. The average score on the ODI improved from 60 preoperatively to 37 at the last follow-up. The VAS score improved from 7 preoperatively to 3 at the last follow-up. There were no reoperations secondary to hardware failure or symptomatic pseudoarthrosis. 


MIS-transpoas LIF at the L4/L5 disc space is a safe, reproducible, and effective technique with low rate of lumbar plexus injury. When careful surgical technique is applied, patient outcomes may be better than in multi level MIS-LIF operations above the L4/L5. MIS-LIF at L4/5 also offers lower intraoperative and wound complications than other popular techniques for this levelMost complications that do occur are transient neuropraxia or mild axonotmesis which resolves within 6 months. Thorough anatomical knowledge of the lumbar plexus and meticulous surgical technique must be taken when operating at this level.