Abstracts

In pediatric epilepsy surgery, seizure-free rate of callosotomy is lower than that of vagal nerve stimulation. And cost-effectiveness of callosotomy is also controversial. In the present study, experimental callosotomy was performed in cats and in rats. Electrophysiological and metabolic approaches were made. Six adult cats and 19 Wistar rats were used. Exp.1. Under intraperitoneal pentobarbital anesthesia, craniotomy was made in all cats and the dura was opened unilaterally. Bipolar electrodes were implanted and EEG recording was made. Three micrograms of kainite was injected into unilateral sensori-motor cortex and focal cortical seizures were elicited. Callosal section was performed using stereotactic coordinates. EEG analysis was made. Exp. 2. Under intraperitoneal pentobarbital anesthesia, femoral artery and femoral veins were canulated. Craniotomy was made in all rats and the dura was opened unilaterally. Two micrograms of kainite was injected into unilateral sensori-motor cortex and focal cortical seizures were elicited. Callosal section was performed using stereotactic coordinates. Intravenous injection of 14C-deoxyglucose was made and the rats were processed for autoradiography. All cats and rats exhibited focal cortical seizures after kainite injection. Exp. 1. Seizure propagation to contralateral cortex was clearly suppressed after callosotomy. But, kainite-induced seizures remained in the focus and seizure propagation was observed in the contralateral thalamus. Exp. 2. After callosotomy, seizure propagation to contralateral cortex(hypermetabolic area) was suppressed. Hypermetabolic area in the focus, ipsilateral basal ganglia and thalamus, and contralateral basal ganglia remained even after callosotomy. Callosotomy may be a surgical option only to reduce seizure activities in the contralateral cortex. But seizure activities of the focus remained even after the callosotomy.