SURG-36. THE EVALUATION OF POSTOPERATIVE MOTOR FUNCTION DEFICITS AFTER SUPRATENTORIAL BRAIN TUMOR SURGERY THROUGH THE ANALYSIS OF INTRAOPERATIVE MEP AND ISCHEMIC LESION ON POSTOPERATIVE DWI

Abstract BACKGROUND The authors investigated the incidence of ischemic lesions on immediate postoperative diffusion-weighted imaging (DWI) according to the findings of intraoperative motor evoked potential (MEP) and the correlation with postoperative motor function deficits. METHODS From January 2016 to June 2018, total 127 supratentorial brain tumor patients were enrolled in this study. The intraoperative MEP results were analyzed in the following three groups: no decline below 50 % of baseline (A), transient decline below 50 % of baseline (B), no recovery until end stage of surgery (C). Postoperative magnetic resonance imaging was performed within 48 hours after surgery. RESULTS Of the total 127 patients, MEP changes (group B&C) were observed in 25 patients (25/127, 19.7%), DWI positive findings were identified in 31 patients (31/127, 24.4%) and motor function deficits were observed in 19 patients (19/127, 15%), respectively. DWI positive finding rate was higher in gliomas (14/43, 32.6%) than meningiomas (8/51, 15.7%) or other tumors including metastasis (6/32, 18.8%), however, there was no statistical significance. In MEP changes, group B&C (16/25, 64%) showed higher DWI positive rate than group A (13/102, 12.7%). In DWI findings, the DWI positive cases (16/31, 51.6%) showed a higher motor function deficit rates than the DWI negative cases (3/96, 3%). These two results were all statistically significant (P<0.01). In group A, motor function deficits were presented in 3 of 13 DWI positive case, all of which were transient. In group B, motor function deficits were presented in 9 out of 13 DWI positive cases with permanent 4 and transient 5. In group C, motor function deficits were presented in 4 out of 5 DWI positive cases with permanent 3 and transient 1. CONCLUSIONS Both intraoperative MEP changes and postoperative DWI positive findings in supratentorial brain tumor surgery were significant related with postoperative motor function deficits. Even if intraoperative MEP changes occur during supratentorial brain tumor surgery, active and appropriate efforts to prevent irreversible MEP changes may reduce the occurrence of permanent postoperative motor function deficits.