Lateral lumbar interbody fusion without intraoperative neuromonitoring: a single-center consecutive series of 157 surgeries

OBJECTIVE Lateral lumbar interbody fusion (LLIF) is frequently used for anterior column stabilization. Many authors have reported that intraoperative neuromonitoring (IONM) of the lumbar plexus nerves is mandatory for this approach. However, even with IONM, the reported motor and sensory deficits are still considerably high. Thus, the authors' approach was to focus on the indication, trajectory, and technique instead of relying on IONM findings per se. The objective of this study therefore was to analyze the outcome of our large cohort of patients who underwent LLIF without IONM. METHODS The authors report on 157 patients included from 2010 to 2016 who underwent LLIF as an additional stabilizing procedure following dorsal instrumentation. LLIF-related complications as well as clinical outcomes were evaluated. RESULTS The mean follow-up was 15.9 +/- 12.0 months. For 90.0% of patients, cage implantation by LLIF was the first retroperitoneal surgery. There were no cases of surgery-related hematoma, vascular injury, CSF leak, or any other visceral injury. Between 1 and 4 cages were implanted per surgery, most commonly at L2-3 and L3-4. The mean length of surgery was 92.7 +/- 35 minutes, and blood loss was 63.8 +/- 57 ml. At discharge, 3.8% of patients presented with a new onset of motor weakness, a new sensory deficit, or the deterioration of leg pain due to LLIF surgery. Three months after surgery, 3.5% of the followed patients still reported surgery-related motor weakness, 3.6% leg pain, and 9.6% a persistent sensory deficit due to LLIF surgery. CONCLUSIONS The results of this series demonstrate that the complication rates for LLIF without IONM are comparable, if not superior, to those in previously reported series using IONM. Hence, the authors conclude that IONM is not mandatory for LLIF procedures if the surgical approach is tailored to the respective level and if the visualization of nerves is performed.