Preoperative navigated transcranial magnetic stimulation in patients with motor eloquent lesions with emphasis on metastasis.

Navigated transcranial magnetic stimulation (nTMS) is a frequently used, non-invasive method to map the motor cortex. It is of great value in the preoperative workup of patients that suffer from motor eloquent brain lesions. Here, we present a single-center experience using preoperative nTMS in cortical motor eloquent lesions with emphasis on metastasis. All patients that underwent preoperative nTMS between June 2013 and January 2016 were evaluated. A total of 61 patients underwent nTMS before undergoing surgery for a motor eloquent brain lesion. Patients suffered from cerebral metastasis (23), glioblastoma (16), high grade glioma WHO III (4), low grade glioma WHO II (4), lymphoma (2), meningioma (8), cavernous hemangioma (3), or arteriovenous malformation (1). Thirty patients (49.2%) presented with a preoperative motor deficit. One week after surgery, paresis had resolved or improved in 56.7% of the patients. Out of the patients with postoperative paresis, 89.5% experienced an improvement of motor status at follow-up. All metastatic lesions were completely resected compared to 78.9% of non-metastatic lesions (P = 0.02). Only 4.3% of patients with a metastatic lesion, but 26.3% of patients with a non-metastatic lesion experienced deterioration of motor function after surgery (P = 0.04). Preoperative nTMS is suitable for mapping of a variety of motor eloquent brain lesions resulting in favorable neurological outcome. Particularly in metastatic motor eloquent lesion, motor function appears to be preserved after surgery. Clin. Anat. 29:925-931, 2016.