[Anesthesia for the intraoperative electrocorticography of patients with uncontrollable epilepsy]

For the surgical treatment of uncontrollable epilepsy, it is essential to delineate the epileptogenic focus by the use of intraoperative electrocorticography. Most general anesthetic agents, however, suppress the epileptogenic focus. Therefore, such a patient is usually kept awake during the procedure using local anesthesia. We experienced 15 cases for these procedures. Anesthesia was induced with thiamylal and pancuronium was administered for tracheal intubation. Anesthesia was maintained with nitrous oxide, oxygen and enflurane or isoflurane. After the brain was exposed, volatile anesthetics were discontinued and replaced with intermittent fentanyl administration. Approximately 15 minutes before the start of intraoperative electrocorticography, nitrous oxide concentration was reduced to 30% or less. A resective epileptogenic focus was identified in every patients. In 2 patients, electrocorticographical focal seizure status was identified following the intraoperative electrocorticography. After the focus resection, seizure attacks were controlled only by the application of regular medical regimen in these patients. Low nitrous oxide and intermittent fentanyl administration can be recommended as a superior anesthesia technique for intraoperative electrocorticography.