OBJECTIVES: To investigate if intraoperative focused high frequency repetitive transcranial magnetic stimulation (rTMS) can localise the primary motor cortex without exposure of the cortical surface. METHODS: A high frequency train (357 Hz) of four suprathreshold magnetic stimuli was delivered transcranially to the region of the rolandic area during @entity1313 operations in 12 @entity1 . To induce a focal magnetoelectric field, the flat figure of eight coil (outer diameter of each loop 7 cm) was used. Motor evoked potentials (MEP) were recorded in eight muscles of the upper and lower contralateral extremities. The first stimulation site was 2.5 cm behind the bregma, the second site 2 cm, and the third site 4 cm dorsal to the first stimulation site. If no MEP were obtainable, stimulation was repeated in anteroposterior direction at more laterally located sites. Using neuronavigation, each positive stimulation site was correlated with the underlying cortical anatomy. RESULTS: Stimulation was performed at a total of 42 sites (in two @entity1 , maximum stimulation at the three initial sites failed to evoke a motor response). In four @entity1 , MEP were obtained only from one stimulation site. This site exactly overlayed the primary motor cortex. In eight @entity1 , MEP could be elicited from more than one stimulation site. In seven of the eight @entity1 , the site from which MEP with peak amplitudes were elicited, corresponded to the primary motor cortex. In total, the primary motor cortex was correctly identified on the basis of electrophysiological findings in 11 of 12 @entity1 (92 %). In two @entity1 , only the more lateral stimulation sites permitted MEP recording. CONCLUSION: Intraoperative focused rTMS is highly sensitive for localisation of the primary motor cortex. Focused rTMS as a localising instrument alleviates the need of motor cortex exposure and, thereby, can contribute to minimise the surgical @entity1313 in the rolandic area.

Focused high frequency repetitive transcranial magnetic stimulation for localisation of the unexposed primary motor cortex during XXXX surgery.

@entity1 :: ('9606', 'Species') :: ['patients'] @entity1313 :: ('MESH:D001932', 'Disease') :: ['brain tumour', 'approach to brain tumours']
@entity1313 :: (MESH:D001932,Disease) :: ['brain tumour']
