Anesthesia in surgery for epilepsy

OBJECTIVES: To evaluate the efficacy of general anesthesia during epileptic surgery. MATERIAL AND METHODS: A retrospective study of 64 patients who received general anesthesia during epileptic surgery. In the preoperative period, anticonvulsive medication was adjusted in accordance with plasma levels and withdrawn entirely 8 hours before surgery. After premedication with droperidol and fentanyl, a balanced anesthetic technique was applied, based on pentothal, pancuronium (or vecuronium), fentanyl, N2O and isoflurane. Continuous monitoring of ECG, arterial blood pressure, pulse oximetry, ET CO2 and neuromuscular function. Isoflurane was stopped for 10 min after the opening of the duramadre so that ECoG could be recorded and methohexital or propofol was given in some cases in order to activate the epileptogenic focus. Muscular relaxation was restored intraoperatively following the study of somatosensory evoked potentials. Immediate and later complications related to anesthesia or surgery were recorded. RESULTS: The surgical procedure performed in most cases was temporal or frontal resection, with a mean duration for anesthesia of 377 +/- 50 min and for surgery of 318 +/- 50 min. Only one patient received local anesthesia and no hemodynamic changes were observed. Perioperative complications were cerebral edema (4 cases), arrhythmia (2 cases) and bronchospasm (1 case). Postoperative complications were as follows: 3 of 9 patients undergoing callosotomy required mechanical ventilation for 24 hours, 4 patients experienced language alterations, 3 wounds were infected, 2 cases of hemiplegia were observed, 1 status epilepticus occurred after administration of propofol and there was 1 case of respiratory distress. Anticonvulsive medication was given parenterally after surgery. CONCLUSIONS: General anesthesia is a safe and effective method for epileptic surgery, with local anesthesia providing additional sedation for isolated cases. Appropriate treatment requires an understanding of the pharmacokinetics and pharmacodynamics of the drugs used, as well as knowledge of the condition and the anticonvulsive medications used.