Table 2.

Clinical studies evaluating MEP utilization during LLIF

Study	Sample Size, treatment, study design	Key findings—benefits of MEP	Key findings—limitations of MEP
Riley et al. [33] (2018)	479 Patients; LLIF with or without posterior decompression and fusion at any level; Retrospective review	Patients who received additional transcranial electric MEP (tcMEP) monitoring had a lower rate of postoperative neurologic deficits compared to patients receiving EMG monitoring only. tcMEP monitoring was associated with decreases in both sensory and motor deficits; tcMEP has potential to monitor sensory function indirectly via monitoring of mixed sensory-motor nerves.	-
Berends et al. [34] (2016)	23 Patients; LLIF at various levels from L1–4; Prospective, single-centered	In 9% of patients, MEP amplitude decreased due to psoas retractor deployment, without a corresponding change in EMG signals.	-
Chaudhary et al. [35] (2015)	3 Patients; LLIF at L4–5; Case series	Intraoperative MEP changes detected without corresponding abnormal EMG activity.	-
Houten et al. [25] (2011)	2 Patients; LLIF at L3–5; Case series	-	Postoperative motor deficits not detected by either EMG or MEP. Motor potentials may vary depending on depth and choice of anesthetic agents.

MEP, motor-evoked potential; EMG, electromyography; LLIF, lateral lumbar interbody fusion.