Planning of minimal destructive neurosurgery: preoperative fMRI and intraoperative cortical stimulation

摘要

With intraoperative stimulation of the brain sensori-motoric areas of the cerebral cortex are localized duringthe operation in order to be able to spare them with the extirpation of tumors, vascular malformations orepilepsy-surgical interventions. The direct intraoperative electric stimulation is helpful in order to minimizepostoperative sensori-motoric deficits as well as disturbances of the language and the ability of speaking.The technology of intraoperative cortical stimulation (ICS) is established only at few clinical facilities since thepatient is operated with inferior narcosis depth or in awake condition. Moreover, the dependable localisationof functional areas is time-consuming, the procedure can be incriminating for the patient and causes due tolonger operation times also considerable cost increases.With functional magnet resonance tomography (fMRI) a technology for preoperative localisation offunctionally important brain areas became available in the last years. The agreement between the results ofICS and the representation of preoperative retained information from fMRI-examinations is little examinedyet. Several international research groups examine whether the preoperative functional magnet resonancetomography can localize eloquent brain areas unequivocally and in what way these results agree with theintraoperative stimulation. The answer to these questions is decisive in order to spare the intraoperativestimulation and the operation in awake condition for the patient in the future. Institutes without the possibilityof intraoperative electro physiology could rely on the preoperative retained results of fMRI and could takethese into account in their operation planning. In a study 1997, Yetkin could prove one certain unisonbetween the fMRI-method and the electric stimulation at the sensory and the visual cortex. Discrepancies inlocalisation of up to 20 millimeters emerged on that occasion. Yousry et al. could prove the hand areasteadily in the Gyrus precentralis by the comparison of ICS with functional MRT [40].