Navigated transcranial magnetic stimulation for mapping the motor cortex in patients with rolandic brain tumors

Abstract

<jats:sec> <jats:title>Object</jats:title> <jats:p>Navigated transcranial magnetic stimulation (nTMS) is a novel technology in the field of neurosurgery for noninvasive delineation of cortical functional topography. This study addresses the spatial accuracy and clinical usefulness of nTMS in brain tumor surgery in or near the motor cortex based on a systematic review of observational studies.</jats:p></jats:sec> <jats:sec> <jats:title>Methods</jats:title> <jats:p>A systematic search retrieved 11 reports published up to October 2012 in which adult patients were examined with nTMS prior to surgery. Quality criteria consisted of documentation of the influence of nTMS brain mapping on clinical decision making in a standardized prospective manner and/or performance of intraoperative direct electrical stimulation (DES) and comparison with nTMS results. Cross-observational assessment of nTMS accuracy was established by calculating a weighted mean distance between nTMS and DES.</jats:p></jats:sec> <jats:sec> <jats:title>Results</jats:title> <jats:p>All studies reviewed in this article concluded that nTMS correlated well with the “gold standard” of DES. The mean distance between motor cortex identified on nTMS and DES by using the mean distance in 81 patients described in 6 quantitatively evaluated studies was 6.18 mm. The nTMS results changed the surgical strategy based on anatomical imaging alone in 25.3% of all patients, based on the data obtained in 87 patients in 2 studies.</jats:p></jats:sec> <jats:sec> <jats:title>Conclusions</jats:title> <jats:p>The nTMS technique spatially correlates well with the gold standard of DES. Its functional information benefits surgical decision making and changes the treatment strategy in one-fourth of cases.</jats:p></jats:sec>

Bringing transcranial mapping into shape: Sulcus-aligned mapping captures motor somatotopy in human primary motor hand area

“…Subject to further confirmation in large-scale studies, our mapping approach constitutes a valuable research tool for studies addressing non-invasive assessments of representational plasticity in M1 HAND since the linear shape-aligned mapping approach reliably captured the homuncular representation within-M1 HAND . The stereotactic guidance of coil placement also renders it possible to take into account dislocation or distortion of the shape of the central sulcus due to brain pathologies, for example in patients with peri-rolandic brain tumours or after motor stroke (Prashantha et al, 2013;Takahashi et al, 2013).…”

A compact theory of magnetic nerve stimulation: predicting how to aim

“…When coils are placed over the motor strips of cerebral cortex, just above the ears, TMS can be used to test the function of motor tracts extending from head to toe or from head to fingertips [8,10,11]. Such testing can be useful in monitoring the functional integrity of the spinal cord during neurosurgery, helping to avoid the dreaded complication of postoperative paralysis [3,12]. When coils are placed further forward over pre-frontal cortex TMS can be used treat psychic depression [8].…”

Navigated Transcranial Magnetic Stimulation for “Somatotopic” Tractography of the Corticospinal Tract

“…Recently, the use of navigated transcranial magnetic stimulation (nTMS) to map the motor cortex has been described. [14][15][16][17][18][19][20][21][22][23][24] In nTMS, conventional transcranial magnetic stimulation (TMS) is combined with sophisticated neuronavigation software that allows the navigation of every "stimulated" point in the cortex. 16,17,20,21 Several studies have already demonstrated the accuracy of this technique by comparing nTMS with functional MRI and direct cortical stimulation.…”