Literature Review of Subcortical Mapping Techniques in Glioblastoma Surgeries

Subcortical mapping of glioblastoma is an intraoperative technique used during tumor resection to identify the motor and language pathways in the central nervous system of the brain that are possibly affected by glioblastoma, an aggressive type of brain tumor that develops from glial cells with poor prognosis. This technique involves using electrical probes in varying brain tissues in an awake patient to stimulate different brain regions and critical areas responsible for language and movement. Combining intraoperative modalities like somatosensory evoked potential (SSEP), direct electrical stimulation (DES), electromyography (EMG), and electrocorticography (ECoG), Electroencephalography (EEG), Train of four (TOF) and Phase reversal, the surgical team can monitor neural activity. Penfield and Taniguchi have developed two methods to map the corticospinal tracts intraoperatively. One of these approaches may be used depending on the tumor's location, the patient's medical history, the surgery, and other considerations. Like other intraoperative monitoring techniques, the use of subcortical mapping during tumor resection in glioblastoma helps surgeons minimize the risk of postoperative deficits with the possibility of improving surgical outcomes for patients with this disease.