Background: In patients with lesions located around or within eloquent motor or speech cortex, surgical resection is a challenge; because of high risk of development of postoperative deficits and incomplete resection. intraoperative neurophysiological monitoring (IONM) paves the way to complete resection in these patients along with functional preservation postoperative. Aim of the study: To assess the utility and effectiveness of IONM techniques in resection of lesions located in eloquent motor speech cortex (intrinsic brain tumors and epileptic zones), regarding the extent of resection and functional preservation postoperative. Patients and Methods: we conducted prospective observational
study on 30 patients with different types of lesions located within eloquent motor or speech cortex, by the use of low frequency direct cortical and subcortical stimulation technique,12 patients were operated under general anaesthesia and 18 patients were operated by awake craniotomy technique.All patients were assessed clinically and do MRI brain with contrast and FLAIR study postoperatively, those who developed new onset neurological deficits were assessed at 3
months postoperative. Results: complete resection was achieved in 17 patients (56.6%). Immediate postoperative new onset or worsened neurological deficits were encountered in 18 patients (60%), however 3 months postoperative the deficits were persistent only in 4 patients (13.3%). Conclusion: direct cortical stimulation is an easy safe and reliable
method for detection of cortical and subcortical functionally eloquent structures during resection of brain tumors and epileptic lesions