Abstract
Preoperative mapping of motor areas with navigated transcranial magnetic stimulation (nTMS) has been shown to improve surgical outcomes for peri-Rolandic lesions and, in particular, for gliomas. However, the impact of this technique on surgical outcomes for peri-Rolandic metastatic lesions is yet unknown. To investigate the impact of nTMS on surgical outcomes for peri-Rolandic metastatic lesions, various clinical parameters were analyzed in our international study group. Two prospectively enrolled cohorts were compared by investigating patients receiving preoperative nTMS (2010-2015; 120 patients) and patients who did not receive preoperative nTMS (2006-2015; 130 patients). Tumor location, pathology, size, and preoperative deficits were comparable. The nTMS group showed a lower rate of residual tumor on postoperative magnetic resonance imaging (odds ratio 0.3025; 95% confidence interval 0.1356-0.6749). On long-term follow-up, surgery-related paresis was decreased in the nTMS group (nTMS vs. non-nTMS; improved: 30.8 vs. 13.1%, unchanged: 65.8 vs. 73.8%, worse: 3.4 vs. 13.1% of patients; p = 0.0002). Moreover, the nTMS group received smaller craniotomies (nTMS: 16.7 ± 8.6 cm2 vs. non-nTMS: 25.0 ± 17.1 cm2; p < 0.0001). Surgical time differed significantly between the two groups (nTMS: 128.8 ± 49.4 min vs. non-nTMS: 158.0 ± 65.8 min; p = 0.0002). This non-randomized study suggests that preoperative motor mapping by nTMS may improve the treatment of patients undergoing surgical resection of metastases in peri-Rolandic regions. These findings suggest that further evaluation with a prospective, randomized trial may be warranted.
Highlights
One indication for surgical resection of cerebral metastases is a focal motor deficit
For supratentorial lesions located in motor eloquent areas, especially gliomas, three prior studies have demonstrated improvement in outcomes when preoperative functional mapping of motor areas is performed by navigated transcranial magnetic stimulation (nTMS) [2,3,4]
NTMS opens up the potential for tracking tumor-induced plasticity and reorganization of the motor system. The occurrence of such functional reorganization has been described using Intraoperative neuromonitoring (IOM); gaining this information non-invasively, would allow a clinician to identify the earliest time point after an initial subtotal resection (STR) when a repeat resection might confer maximal benefit with minimal risk [5, 43,44,45,46,47]. This non-randomized study suggests that preoperative motor mapping by nTMS may improve the treatment of patients undergoing surgical resection of metastases in peri-Rolandic regions
Summary
One indication for surgical resection of cerebral metastases is a focal motor deficit In these patients, early surgery is often recommended so as to preserve existing function and, hopefully, to allow recovery of lost function. Continuous motor-evoked potential (MEP) monitoring and subcortical electrical stimulation are two well-established techniques to monitor and map functional integrity of the motor system. Another technique, navigated transcranial magnetic stimulation (nTMS), which uses magnetic pulses to activate small regions of cortex, has demonstrated the ability to map the motor system in the preoperative setting. For supratentorial lesions located in motor eloquent areas, especially gliomas, three prior studies have demonstrated improvement in outcomes when preoperative functional mapping of motor areas is performed by nTMS [2,3,4]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
