脳梁離断術が有用であったepileptic spasmを主症状とする難治性小児てんかんの1例

A Case of Intractable Epilepsy Presenting Epileptic Spasm Treated with Callosotomy in Childhood

　Ⅰ．はじめに

現在，難治性てんかんに対する外科手術の中で脳梁離断術は遮断手術の1つとして用いられており，手術例の70％近くで発作が軽減することが報告されている⁷⁾．しかし，脳梁離断術は発作型では脱力失立発作，てんかん分類ではLennox-Gastaut症候群，両側の前頭葉てんかんなどがよい適応とされているものの，厳密な手術適応基準がないことが問題として挙げられる．今回われわれは脳梁離断術が有効であったepileptic spasmを主症状とする難治性小児てんかんの1症例を経験し，手術適応に関して若干の知見を得たので文献的考察を加え報告する．

　We present a case of intractable epilepsy presenting epileptic spasm successfully treated with anterior callosotomy in childhood. A 12-year-old boy had seizures frequently since the age of 11 months which were diagnosed as an infantile spasm. He underwent various treatments including ACTH therapy,but the seizures were intractable. Characteristics of his seizures were an abrupt axial movement leading to sustained posturing,most often truncal,and neck flexion with pronounced arm extension and abduction. He lost consciousness transiently and these seizures frequently occured in clusters and the duration of seizure was 1 to 3 seconds. Neurologically he had no deficit,but his intelligence was below the standard level. Magnetic resonance image (MRI) showed no abnormalities in the brain. Electroencephalogram (EEG) demonstrated secondary bilateral synchrony (SBS) with left frontal dominance in amplitude. Subdural strip electrodes were implanted bilaterally over the frontal lobes to detect an epileptogenic region. However intracranial ictal-EEG demonstrated an abrupt bilateral desynchronization for 1-3 seconds. As the epileptogenic zone was not clearly identified and an abrupt bilateral desynchronization was identified,anterior callosotomy was performed. Since surgery,he has remained seizure-free for two years while taking anticonvulsants and the SBS has disappeared. This case may indicate that the corpus callosum influences the occurrence of epileptic spasm and SBS on EEG.