Selective electroencephalograph-guided microsurgical callosotomy for refractory generalized epilepsy.

Between 1978 and 1985, 35 patients with medically refractory multiform seizures were submitted for sections of variable portions of the corpus callosum. Guided by intraoperative electroencephalographic and electrocorticographic monitoring, the section was carried out only in the portion of callosum that was involved in the maintenance of the bilaterally synchronous slow spike and wave discharge (as documented by intraoperative electrocorticography). In our patients, only part of the frontal corpus callosum needed to be sectioned to interrupt the bilateral synchrony of epileptic discharge. Of the 35 patients, operated on, 28 have had an adequate long-term follow up and are presented herein. All had significant improvement in seizure frequency and psychosocial functioning.