[P2-110] A case of intractable hemispheric epilepsy successfully treated by the combination of VNS and total callosotomy
In our department, callosotomy is the first choice for drop attack, and Vagus Nerve Stimulation (VNS) is selected for other seizure types because of its less invasiveness. However if the first operation is not effective, sometimes both operations are performed in combination. We present a case of intractable hemispheric epilepsy obtained a good outcome by the combination of both operations. The patient was a 12-year-old boy with a past history of asplenia and single ventricle. He suffered from pneumococcal meningitis and a right middle cerebral artery infarction at 5 years old. His first seizure was at the age of 8 years. Because his seizures were variable, frequent and resistant to many antiepileptic drug, he was referred to our department. The seizure focus was thought to be in the extended right hemisphere with preoperative evaluation. He was performed VNS system implantation at 10 years old. Subsequently, the stimulation current was gradually increased in regular visits to assess efficacy. However, seven months after first surgery, a new seizure type was described as drop attack occurring several times a week (1.5mA, duty cycle 25%). Because video- electroencephalogram showed bilateral synchronized discharges, he was performed one-stage total callosotomy at 12 years old. Recently, he had only an atypical absence once a month. Several hypotheses have been proposed, including: callosotomy has an effect on propagation, and VNS has an effect on seizure onset. Due to their different mechanisms, it was suggested that good outcome could be obtained by performing both operations on the same patient.