Maximally safe resection of gliomas near eloquent areas through intra-operative direct electrical stimulation

Objective To report our experiences of direct electrical stimulation in surgery of gliomas near eloquent areas.Methods A retrospective analysis of the clinical data for 157 patients with supratentorial gliomas that underwent awake craniotomy,with direct electrical stimulation for functional mapping of eloquent areas,was performed.The maximal resection of tumors and the minimal damage of eloquent areas were the surgical goals of all patients.Results Negative cortical stimulation was found in four patients,and positive cortical stimulation was achieved in 153 patients (97.5％).Additionally,496 cortical sites in 139 patients were detected for motor response through direct electrical stimulation,70 sites in 21 patients detected for sensory,and 112 sites in 91 patients detected for language (such as counting and naming).In the 86 cortical sites for counting,41 (47.7％) sites were located on the lower parts of the left precentral gyri,21 on the left pars opercularis,11 on the left pars triangularis,9 on the posterior parts of the left middle frontal lobe,and 4 on the posterior part of the left superior frontal lobe.Post-operative MR showed that 92 patients (58.6％) achieved total resection; with 55 (35.0％) subtotal and 10 partial.Furthermore,77 patients (49.0％) had no postoperative deficits; however,53 patients (33.8％) had transitory post-operative paralysis,39 patients (24.8％) had transitory language disturbances and 4 patients (2.5％) had permanent neurological deficits.Conclusions Intra-operative direct electrical stimulation is a reliable,precise,and safe method for functional mapping of the eloquent areas.This technique allows neurosurgeons to achieve maximally safe resectionin glioma surgery.It can also provide an important new way for Chinese brain mapping. Key words: Gliomas;  Brain mapping;  Direct electrical stimulation;  Awake craniotomy