Corpus callosotomy: clinical and electroencephalographic effects.

Six persons (five male, one female), 15-41 years of age (mean, 23 years), with medically intractable epilepsy for 7-35 years (mean, 15 years) underwent total corpus callosum section (anterior commissure to posterior commissure) for treatment of seizures resulting in falls and injuries. Preoperative EEGs demonstrated two or more morphologically distinct interictal discharges, at least one of which was generalized. Generalized ictal EEG discharges were documented in all cases to account for the clinical seizures resulting in injury. A comparison of generalized epileptiform discharges in comparable states of arousal pre- and postoperatively demonstrated a statistically significant (p less than 0.05) reduction of generalized discharges after surgery. Postoperative observation periods have ranged from 10 to 30 months (mean, 17.6 months) and have documented a statistically significant (p less than 0.05) decrease in the number of falling seizures (means: preoperative, 23.2 seizures/month; postoperative, 0.7 seizures/month). A statistically significant difference in pre- and postoperative total (generalized and focal) interictal discharges was not demonstrated. Long-term, clinically apparent complications of surgery did not occur in our patients. Thus, sectioning of the corpus callosum interrupts generalized epileptiform discharges (as documented by the postoperative EEG) and usually results in a significant decrease in generalized seizures.