title: Resection of Motor Eloquent Metastases Aided by Preoperative nTMS-Based Motor Maps-Comparison of Two Observational Cohorts.
abstract: BACKGROUND
  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.
  
  
  OBJECTIVE
  To investigate the impact of nTMS on surgical outcomes for peri-Rolandic metastatic lesions, various clinical parameters were analyzed in our international study group.
  
  
  METHODS
  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.
  
  
  RESULTS
  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 cm2vs. 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).
  
  
  CONCLUSIONS
  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.
authors.affiliation: Department of Neurosurgery, Klinikum rechts der Isar, Technische Universität München , Munich , Germany.
authors.forename: Sandro M
authors.initials: SM
authors.lastname: Krieg
authors.affiliation: Department of Neurosurgery, Charité - Universitätsmedizin Berlin , Berlin , Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Picht
authors.affiliation: Department of Neurosurgery, Klinikum rechts der Isar, Technische Universität München , Munich , Germany.
authors.forename: Nico
authors.initials: N
authors.lastname: Sollmann
authors.affiliation: Department of Neurosurgery, Charité - Universitätsmedizin Berlin , Berlin , Germany.
authors.forename: Ina
authors.initials: I
authors.lastname: Bährend
authors.affiliation: Department of Neurosurgery, Klinikum rechts der Isar, Technische Universität München , Munich , Germany.
authors.forename: Florian
authors.initials: F
authors.lastname: Ringel
authors.affiliation: Biomagnetic Imaging Laboratory, Department of Radiology, University of California San Francisco , San Francisco, CA , USA.
authors.forename: Srikantan S
authors.initials: SS
authors.lastname: Nagarajan
authors.affiliation: Department of Neurosurgery, Klinikum rechts der Isar, Technische Universität München , Munich , Germany.
authors.forename: Bernhard
authors.initials: B
authors.lastname: Meyer
authors.affiliation: Department of Neurological Surgery, University of California San Francisco , San Francisco, CA , USA.
authors.forename: Phiroz E
authors.initials: PE
authors.lastname: Tarapore
keywords: Rolandic region; brain metastases; matched pair; preoperative mapping; transcranial magnetic stimulation