天幕下脳動静脈奇形が原因をなした症候性三叉神経痛の1例

A CASE OF SYMPTOMATIC TRIGEMINAL NEURALGIA CAUSED BY ARTERIOVENOUS MALFORMATION IN THE POSTERIOR FOSSA

いとぐち

　三叉神経痛は日常の臨床においてしばしば遭遇する疾患であり，明らかな原因疾病を有しない特発性三叉神経痛と他の疾病の一症状として出現する症候性三叉神経痛とに大別される。

　症候性三叉神経痛の原因としては中頭蓋窩および小脳橋角部の髄膜腫，神経鞘腫，epidermoid,cholesteatomasなどの脳腫瘍，天幕下脳動静脈奇形，脳底動脈瘤，内頸動脈瘤などの血管奇形，その他閉塞性血管障害および中頭蓋窩侵潤癌が報告されているが，これらのうち天幕下脳動静脈奇形が三叉神経痛の原因であつた症例はきわめて稀であり，文献中に10数例の報告をみるにすぎない。症候性三叉神経痛症例では三叉神経痛とともに当然ながら原疾患である脳腫瘍や血管奇形にもとずく神経症状を併有することが多いが，中には症候性三叉神経痛でありながら他に神経症状なくWhite　＆　Sweet^26）よつて提案された5条件を完全に具備している症例もある。

The most important point of treatment in the trigeminal neuralgia is to differentiate the idiopa-thic trigeminal neuralgia form the symptomatic trigeminal neuralgia. The criteria of the idiopa-thic trigeminal neuralgia had been reported by White & Sweet but some cases of the symptomatic trigeminal neuralgia who showed the typical feat ures of the idiopathic trigeminal neuralgia in their early stage were reported in the literatures. The authors experienced a case, 43 year-old male, in whom an arteriovenous malformation in the area adjacent to pons was a cause of the trigeminal neuralgia and was treated as idiopathic trigeminal neuralgia for long time before the attak of subar-achnoid hemorrhage. By review the literatures, the authors found 12 cases of arteriovenous malf-ormation in the posterior fossa caused the trigem-inal neuralgia and emphasized the following points ;

1) The age of onset in case of the symptomatic trigeminal neuraglia caused by the arteriove- nous malformation in the posterior fossa is younger than that of the idiopathic trigeminal neusalgia and the average age of former is 24.8 year old.

2) In cases of the trigeminal neuralgia who had their onset under 40 year old, the detail neu- rological examination including the cerebral angiography should be done.

3) Removal of arteriovenous malformation in the posterior fossa is a principal treatemnt but pain relief of the trigeminal neuralgia is possible by neurotomy alone when removal of arteriovenous malformation is not indicated.