Navigated transcranial magnetic stimulation-guided resection of a left parietal tumor: case report.

BACKROUND: Operating on tumors with close margins to the primary motor cortex requires a precise preoperative planning. Transcranial magnetic stimulation (TMS) is the only preoperative technique for detecting eloquent cortical regions that is directly comparable to direct cortical stimulation (DCS). Combining this well established method in neurological diagnostics with a non-invasive navigation system using the patient's preoperative MRI scans in the NEXTSTIM system might be a promising tool in preoperative planning. CASE REPORT: We used preoperative navigated TMS to localize the motor strip in a 75-year-old female patient with a central lesion suspected to be a meningeoma. The elicited data were fused to the navigation MRI in the Brainlab IPLAN system. Following the preoperatively acquired MEP data, a posterior approach to the tumor was planned. After craniotomy, DCS and phase reversal were performed to verify the preoperative results. The motor strip could be located in the same cortical area where the motor response was elicited preoperatively CONCLUSION: Navigated transcranial cortical stimulation via the NEXTSTIM system is a helpful tool for preoperative planning.