CORPUS CALLOSOTOMY FOR MEDICALLY INTRACTABLE SEIZURES

To identify factors influencing outcome and morbidity in patients sele cted for corpus callosotomy, we retrospectively reviewed 23 patients w ith intractable generalized seizures who underwent corpus callosotomy between 1991 and 1994. Three patients had a complete corpus callosotom y, while 20 had an anterior callosotomy. Three of those patients subse quently had completion of the anterior callosotomy. Overall, 41% of pa tients were nearly or completely free of the seizure types targeted fo r surgical treatment, while another 45% had seizures less than half as frequently. Four patients developed simple partial motor seizures aft er callosotomy. A transient disconnection syndrome was observed in 57% of patients. The best predictor of good outcome was a normal preopera tive MRI. Mentally retarded patients had poorer outcomes. Outcome was not predicted by extent of callosal section or lateralization on neuro logical examination, EEG, MRI, and SPECT. Completion of anterior callo sotomy resulted in significant reductions in seizure frequency. Though most patients do not become seizure-free after corpus callosotomy, wo rthwhile palliation of an otherwise intractable illness can be achieve d. An analysis of prognostic factors should lead to better selection o f patients for surgery.