Research Fellow NYU Langone Medical Center Paterson, NJ, US
Introduction: The single position MIS lateral approach allows access to the anterior and posterior columns with the patient positioned in the lateral decubitus position. The purpose of this approach was to mitigate complications associated with open procedures while achieving circumferential fusion. More recently, an alternative prone-lateral technique has been developed streamlining surgical access with potential advantages. The purpose of this study was to identify differences in intraoperative neurophysiological monitoring (IOM) rates between single position lateral decubitus and prone-lateral patients during MIS spine surgery.
Methods: MIS patients with available surgical positioning and IOM data were included if they were in a single position. Patients were stratified into 2 groups based on operative positioning: Lateral decubitus [Lat] and Prone Lateral [PL]. IOM was performed using somatosensory evoked potentials (SSEPs) and electromyography (EMG) techniques. An abnormal event was defined as any confirmed loss of signal during the operative period. Means comparison tests and regression analysis assessed differences between patient groups.
Results: 226 (42%) had available positioning and IOM data. Of these, 88 met inclusion criteria (52 Lat and 36 PL). The majority were male (49, 55.7%), mean age of 49.2 yrs and 2.0 levels fused and 18 (20.5%) undergoing an osteotomy. In total, 19 (21.6%) patients had an abnormal IOM event. There was a significant difference in abnormal IOM event rates for patients who were in Lat (31%) and PL (8%) positioning, p=0.012. Multivariate regression adjusting for surgical invasiveness showed that PL patients were 76.8% less likely to experience an abnormal IOM event than Lat patients (OR .232 [CI .060-.905], p=.035).
Conclusion : Lateral decubitus positioning appears to be independently associated with abnormal intraoperative neurophysiological monitoring events when compared to prone lateral positioning during minimally invasive spine surgery. This has the potential to help with risk stratification in the future when determining patients undergoing a single position procedure.
