Callosotomy has been considered as a palliative therapy for refractory epilepsy patients with non-focal onset seizures. Residual partial seizures and unilateral epileptiform discharges on electroencephalography (EEG) are sometimes observed after callosotomy. These findings suggest that some patients may be candidates for subsequent resective surgery. Of 149 children who received a callosotomy, resective/disconnective surgery was subsequently performed in 19 patients. Most patients had generalized seizures and epileptiform discharges on EEG before callosotomy. Two-third had normal neuroimaging studies at initial presurgical evaluation. After callosotomy, ictal symptoms evolved into asymmetric features suggesting partial onset seizures. Post-callosotomy EEG showed completely lateralized or localized epileptiform discharges responsible for residual partial seizures in 16 of 19 patients. Fifteen patients underwent resective surgery of the unilateral frontal lobe, and the remaining received hemispherotomy or posterior quadrantectomy. After subsequent surgery, favorable seizure outcomes were obtained in 11 patients (57.9%). Favorable seizure outcomes may be achieved with callosotomy and subsequent surgery in selected patients who are not candidates for a conventional resective surgery at initial presurgical evaluation.
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