A Retrospective Study of Surgical Correction for Spinal Deformity with and without Osteotomy to Compare Outcome Using Intraoperative Neurophysiological Monitoring with Evoked Potentials

BACKGROUND This study aimed to evaluate the effects of different combined evoked potentials monitoring modes for non-osteotomy and osteotomy surgery of spinal deformity, and to select individualized modes for various surgeries. MATERIAL AND METHODS We retrospectively reviewed a total of 188 consecutive cases undergoing spinal deformity correction. All patients were classified into 2 cohorts: non-osteotomy (Group A) and osteotomy (Group B). According to intraoperative evoked potential monitoring mode, Group A was divided into 2 sub-groups: A1 [spinal somatosensory evoked potential (SSEP)/motor evoked potential (MEP), n=67)] and A2 [SSEP/MEP/descending neurogenic evoked potential (DNEP), n=52]. Group B was classified as B1 (SSEP/MEP, n=27) and B2 (SSEP/MEP/DNEP, n=42). The demographics, surgical parameters, and evoked potential events of different combined monitoring modes were analyzed within each group. RESULTS The baselines of SSEP/MEP/DNEP in all cases were elicited successfully. Three cases with evoked potential (EP) events (2 with MEP changes and 1 with SSEP/MEP change) were noted in Group A1 and 1 with SSEP change in Group A2, with no neurological complications. Thirteen cases in Group B1 were positive for MEP intraoperatively, including 16 EP events (13 with MEP change and 3 with both SSEP+MEP changes), with no neural complications. In Group B2, 15 cases had 21 EP events, including 12 with MEP change and 2 with SSEP+MEP changes, with no complications. Postoperative neurological complications were observed in 5 of the 7 cases with SS4EP/DNEP changes. CONCLUSIONS Intraoperative simultaneous SSEP/MEP can effectively reflect neurological function in non-osteotomy spinal surgery patients. Simultaneous SSEP/MEP/DNEP can effectively avoid the unnecessary interference by false-positive results of MEP during osteotomy.