Navigated transcranial magnetic stimulation for preoperative functional diagnostics in brain tumor surgery.
OBJECTIVE
Transcranial magnetic stimulation (TMS) is a noninvasive method for analyzing cortical function. To utilize TMS for presurgical functional diagnostics, the magnetic impulse must be precisely targeted by stereotactically positioning the coil. The aim of this study was to evaluate the usefulness of TMS for operation planning when combined with a sensor-based electromagnetic navigation system (nTMS).


METHODS
Preoperative functional mapping with nTMS was performed in 10 patients with rolandic tumors. Intraoperative mapping was performed with the "gold standard" of direct cortical stimulation. Stimulation was performed in the same predefined 5-mm raster for both modalities, and the results were compared.


RESULTS
In regard to the 5-mm mapping raster, the centers of gravity of nTMS and direct cortical stimulation were located at the same spot in 4 cases and at neighboring spots in the remaining 6 cases. The mean distance between the tumor and the nearest motor response ("safety margin") was 7.9 mm (range, 5-15 mm; standard deviation, 3.2 mm) for nTMS and 6.6 mm (range, 0-12 mm; standard deviation, 3.4 mm) for direct cortical stimulation.


CONCLUSIONS
nTMS allowed for reliable, precise application of the magnetic impulse, and the peritumoral somatotopy corresponded well between the 2 modalities in all 10 cases. nTMS is a promising method for preoperative functional mapping in motor cortex tumor surgery.
Picht
Thomas
T
Department of Neurosurgery, Charité-Universitaetsmedizin, Berlin, Germany. thomas.picht@charite.de
Mularski
Sven
S
Kuehn
Bjoern
B
Vajkoczy
Peter
P
Kombos
Theodoros
T
Suess
Olaf
O
D000328:Adult; D000368:Aged; D015415:Biomarkers; D001931:Brain Mapping / Q000295:instrumentation / Q000379:methods; D001932:Brain Neoplasms / Q000175:diagnosis* / Q000503:physiopathology / Q000601:surgery*; D003952:Diagnostic Imaging / Q000295:instrumentation / Q000379:methods*; D019054:Evoked Potentials, Motor / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009044:Motor Cortex / Q000033:anatomy & histology / Q000502:physiology / Q000601:surgery*; D038361:Neuronavigation / Q000295:instrumentation / Q000379:methods*; D017063:Outcome Assessment, Health Care / Q000379:methods; D011183:Postoperative Complications / Q000209:etiology / Q000503:physiopathology / Q000517:prevention & control; D011237:Predictive Value of Tests; D011300:Preoperative Care / Q000295:instrumentation / Q000379:methods*; D050781:Transcranial Magnetic Stimulation / Q000295:instrumentation / Q000379:methods*; D016896:Treatment Outcome
D015415:Biomarkers