Neuromonitoring in Lateral Approaches for Lumbar Interbody Fusion: A Systematic Review

Background: The modality of intraoperative neuromonitoring (IONM) in lateral approaches for interbody fusion varies. We aim to examine the types of neuromonitoring used in lateral approaches for lumbar interbody fusion and associated neurologic complications.

Methods: A systematic review was performed using the Preferred Reporting Items for Systematic Reviews and Meta Analyses guidelines. PubMed and Embase databases were searched from inception to July 2022 for articles examining lateral approaches for lumbar interbody fusion of lateral lumbar interbody fusion (LLIF) or oblique lateral interbody fusion (OLIF) with IONM modalities. Lateral approaches for lumbar interbody fusion with/without IONM was included. Articles without original patient data, case reports with fewer than 2 patients, non-English articles, nonlateral procedures, and nonhuman studies were excluded. The Risk of Bias in Non-randomized Studies-of Interventions tool was used to assess for bias.

Results: A total of 34 studies were included. Twenty LLIF articles had IONM, whereas 1 LLIF article did not have IONM. Three OLIF articles specified IONM, whereas 6 OLIF articles did not have IONM. Two articles had patients undergoing either LLIF or OLIF. For LLIF, overall neurologic complications, motor weakness, and sensory deficits were 19.8%, 7.6%, and 10.6%, respectively. OLIF overall neurologic complications, motor weakness, and sensory deficits were 5.9%, 2.9%, and 3.2%, respectively. Neurologic outcomes with IONM were not superior compared to without IONM in either LLIF or OLIF.

Conclusions: Neurologic complication rates in LLIF remain high despite utilization of IONM. Use of IONM did not benefit neurologic outcomes. More prospective studies with different IONM modalities and without IONM are needed before determining specific benefits or shortcomings of each IONM modality.