Assesment of Functional Results for the Lesions Located in Eloquent Areas with Using Intraoperative Cortical-Subcortical Stimulation and Cortical Mapping

Abstract

AIM: To assess the classical and functional imaging features of patients with pathology located in the eloquent areas of the brain who were admitted to our centre between October 2012 and February 2018. We also studied intraoperative somatosensory evoked potential (SEP), motor evoked potentials (MEP), phase reversal, cortical mapping, the extent of resection and the calculation of postoperative morbidity. MATERIAL and METHODS: We compared our results with previous studies in which this technique was not used. The patient records of 163 patients were reviewed retrospectively after approval by the institutional ethics committee and comparisons were made with reports in the literature. RESULTS: The lesion was localised in the visual cortex in eight of the 163 patients. We did not encounter any abnormality in the VEP recordings, so the surgeries were continued. The remaining 155 cases were followed by intraoperative SEP and MEP monitoring. We observed a greater than 50% decrease in the amplitude and an increase in latencies that was greater than 10% in intraoperative MEP and SEP monitoring in 24 patients of 155. Although 8 of 24 patients with abnormal SEP and MEP values were corrected with manuveurs, 6 patients developed increased neurological deficits postoperatively. CONCLUSION: In conclusion, all of these methods should not be seen as competitive with each other; they could be considered as complementary. All of these methods are helpful for a surgical team regarding loss of neurological function. The rate of loss might be up to 100% and irreversible despite corrective maneveurs.