Background Successful treatment of gliomas in or adjacent to language areas constitutes a major challenge to neurosurgery. The present study was performed to evaluate the procedure of language mapping via intraoperative direct cortical electrical stimulation under awake anaesthesia when performed prior to resective glioma surgery. Methods Thirty patients with gliomas and left-hemisphere dominance and, who underwent language mapping via intraoperative direct cortical electrical stimulation under awake anaesthesia before resective glioma surgery, were analyzed retrospectively. All patients had tumors in or adjacent to cortical language areas. The brain lesions were removed according to anatomic-functional boundaries with preservation of areas of language function. Both preoperative and postoperative functional findings were evaluated. Results Intraoperative language areas were detected in 20 patients but not in four patients. Language mapping failure for reasons attributable to the anaesthesia or to an intraoperative increase in intracranial pressure occurred in six cases. Seven patients presented with moderate or severe language deficits after six months of follow-up. Total resection was achieved in 14 cases, near-total resection in 12 cases and subtotal resection in four cases. Conclusions Intraoperative cortical electrical stimulation is an accurate and safe approach to identification of the language cortex. Awake craniotomy intraoperative cortical electrical stimulation, in combination with presurgical neurological functional imaging to identify the anatomic-functional boundaries of tumor resection, permits extensive tumor excision while preserving normal language function and minimizing the risk of postoperative language deficits.
