Seizure outcomes after anterior callosotomy in patients with posterior-dominant and with anterior-dominant epileptiform discharges

Objects: We wished to find whether there was any difference in the postoper ative seizure outcome between patients with bisynchronous anterior-dominant and those with posterior-dominant EDs after anterior callosotomy. Methods: Seizure outcomes after anterior callosotomy in 7 patients with bisynchrono us posterior-dominant epileptiform discharges and in 54 patients with anter ior-dominant seizures were compared. All 61 cases had been followed up for more than 2 years after operation. One patient (14.3%) had become seizure f ree. Two patients (28.6%) had more than 50% reduction in seizure frequency, but 4 patients (57.2%) showed no improvement at all. The percentage of cas es with significant improvement (more than 50% reduction of seizure frequen cy) was 43% (3 in 7), which is lower than in the patients with bisynchronou s anterior-dominant EDs (64.8%). Conclusions: Our preliminary results sugge st that anterior partial callosotomy could still be helpful in cases with b isynchronous posterior-dominant epileptiform discharges but the prognosis m ay be less optimistic than for those with anteriorly located discharges.