The utility of intraoperative neuromonitoring on simple posterior lumbar fusions—analysis of the national inpatient sample

Background: Several studies have demonstrated the utility of intraoperative neuromonitoring (IOM) including somatosensory evoked potentials (SSEPs), motor-evoked potentials (MEPs), and electromyography (EMG), in decreasing the risk of neurologic injury in spinal deformity procedures. However, there is limited evidence supporting the routine use of IOM in elective posterolateral lumbar fusion (PLF). Methods: The National Inpatient Sample (NIS) was analyzed for the years 2012–2015 to identify patients undergoing elective PLF with (n=22,404) or without (n=111,168) IOM use. Statistical analyses were conducted to assess the impact of IOM on length of stay, total charges, and development of neurologic complications. These analyses controlled for age, gender, race, income percentile, primary expected payer, number of reported comorbidities, hospital teaching status, and hospital size. Results: The overall use of IOM in elective PLFs was found to have increased from 14.6% in the year 2012 to 19.3% in 2015. The total charge in hospitalization cost for all patients who received IOM increased from $129,384.72 in 2012 to $146,427.79 in 2015. Overall, the total charge of hospitalization was 11% greater in the IOM group when compared to those patients that did not have IOM (P<0.001). IOM did not have a statistically significant impact on the likelihood of developing a neurological complication. Conclusions: While there may conceivably be benefits to the use of this technology in complex revision fusions or pathologies, we found no meaningful benefit of its application to single-level index PLF for degenerative spine disease.