P016 Electrophysiological examination combined with functional intraoperative navigation using TMS of the motor cortex in patients with brain tumors in the vicinity of the central region

Abstract

Question Surgery in the area of the motor cortex demands a combination of different neurological and image based examinations to improve outcome of the patients. Some examinations like intraoperative monitoring (IOM) with sensory evoked potentials (SEP) are established standard procedures. The question of our study is if the combination with presurgical transcranial magnetic brain stimulation (TMS) and its use combined with intraoperative navigation may improve the safety of the surgical procedure and neurological outcome. Obejctive and methods A prospective study including preoperative neurological and electrophysiological examination with SEP and TMS (MagPro R30, 230 V) was conducted. During surgery the TMS data combined with Neuronavigation LOCALITE were correlated with the intraoperative monitoring (IOM). Between 24 h and 96 h after the operation and after 3 months a neurological, electrophysiological examination and an additional TMS stimulation were performed. Results A total of 17 patients, with tumors nearby or in the motor cortex were included in the study. 9 patients completed either the whole study or were included in the pre- and the first postoperative examination. During the IOM including SEP, 5 out of 9 patients showed stable results, 3 showed persistent alterations, 1 showed a temporary change. 6 patients (66%), with the stable results and the temporary change, did not show a new neurological deficit. A preserved continuity of intraoperative SEP‘s leads to an improvement of the postoperative clinical outcome. The intraoperative SEP, as a valid method, matched 100 % with the postoperative outcome. The TMS data included in the intraoperative navigation correlated exactly with the intraoperative electrophysiological examination. A correspondence between the intraoperative findings, postoperative electrophysiological and neurological examination was found. Conclusion In summary the TMS as a nonvasive method provides data for constant representability of the motor cortex during surgery. In addition, with the intraoperative SEP’s, it contributes to a reduced surgical scope and finally an enhanced clinical outcome.