P025 Resection of highly language-eloquent brain lesions purely based on rTMS language mapping without awake surgery

Abstract

Introduction The resection of left-sided perisylvian brain lesions harbors the risk of postoperative language impairment. Therefore the individual patient’s language distribution is investigated by intraoperative direct cortical stimulation (DCS) during awake surgery. Yet, not all patients qualify for awake surgery. Non-invasive language mapping by repetitive navigated transcranial magnetic stimulation (rTMS) has frequently shown a high correlation in comparison with the results of DCS language mapping in terms of language-negative brain regions. Objective To analyze the oncological and functional outcome of patients who underwent left-sided perisylvian resection of brain lesions purely based on rTMS language mapping. Patients & methods Four patients with left-sided perisylvian brain lesions (2 gliomas WHO III, 1 glioblastoma, 1 cavernous angioma) underwent rTMS language mapping prior to surgery. Data from rTMS language mapping and rTMS-based diffusion tensor imaging fiber tracking (DTI-FT) were transferred to the intraoperative neuronavigation system. Preoperatively, 5 days after surgery (=POD5), and 3 months after surgery (=POM3) clinical follow-up examinations were performed. Results No patient suffered from a new surgery-related aphasia at POM3. Three patients underwent complete resection immediately, while one patient required a second rTMS-based resection some days later to achieve the final, complete resection. Conclusion The present study shows for the first time the feasibility of successfully resecting language-eloquent brain lesions purely based on the results of negative language maps provided by rTMS language mapping and rTMS-based DTI-FT. In very select cases this technique can provide a rescue strategy with an optimal functional and oncological outcome when awake surgery is not feasible.