BACKGROUNDThe goal of surgery in the treatment of intrinsic cerebral tumors is to resect the maximum tumor volume, and to spare the eloquent areas. However, it is difficult to discover the eloquent areas intraoperatively due to individual anatomo-functional variability both for sensori-motor and language functions. Consequently, the surgery of intrinsic cerebral tumors frequently results in poor extent of resection or permanent postoperative deficits, or both, and remains a difficult problem for neurosurgeons.

METHODSFrom January 2003 to January 2010, 112 patients with neuroepithelial tumors in/close to the eloquent areas were operated on under awake anesthesia with the intraoperative direct electrical stimulation for functional mapping of the eloquent areas. The extent of the tumors was verified by intraoperative ultrasonography. The maximal resection of the tumors and minimal damage of the eloquent areas were the surgical goal of all patients.

RESULTSTotally 356 cortical sites in 99 patients were detected for motor response by intraoperative direct electrical stimulation, 50 sites in 16 patients for sensory, 72 sites in 48 patients for language. Sixty-six patients (58.9%) achieved total resection, 34 (30.4%) subtotal and 12 (10.7%) partial. Fifty-eight patients (51.8%) had no postoperative deficit, while 37 patients (33.0%) had transitory postoperative paralysis, 26 patients (23.2%) with transitory postoperative language disturbance and 3 patients (2.7%) with permanent neurological deficits. No patient complained of pain recollection following operation.

CONCLUSIONSAwake anesthesia, intraoperative direct electrical stimulation and ultrasonography are three core techniques for the resection of intrinsic cerebral tumors near the eloquent areas. This new concept allows an improvement in the quality of surgery for neuroepithelial tumors in/adjacent to eloquent areas.