Persistent Trigeminal Artery Variantに合併した海綿静脈洞部内頸動脈瘤破裂による1くも膜下出血例

Intracavernous Internal Carotid Artery Aneurysm Associated with Persistent Trigeminal Artery Variant:Case report

I．はじめに

　1972年Tealら^14）が，内頸動脈より分岐し脳底動脈に直接終わらず小脳動脈へ終枝する異常血管をpersistent trigeminal artery variant（PTAV）と命名して以来今までに多くのPTAV例が報告されている．また，persis—tent trigeminal artery（PTA）に海綿静脈洞内内頸動脈瘤が合併しやすいことは一般に知られているが，PTAVに同部動脈瘤が合併した報告はわれわれが知るかぎり，3例のみである．今回著者らはくも膜下出血にて発症し，PTAVの海綿静脈洞内起始部に動脈瘤を合併した1症例を経験し，直達手術を施したので文献的考察を加えて報告する．

The authors report a case of an intracavernous internal carotid artery aneurysm associated with a persistent trigeminal artery variant (PTAV). A 47-year-old-woman developed a subarachnoid hemorrhage due to the rupture of aneurysm and underwent direct clipping op-eration. PTAV is basically an anomalous anastomosis between the internal carotid artery and the anterior in-ferior cerebellar artery. In this patient, the PTAV origi-nated from the C4 portion of the right internal carotid artery and distributed in the territory of the hemispheric branch of the posterior inferior cerebellar artery. There have been only three reported cases of the internal caro-tid artery aneurysms arising from the crotch of PTAV. It is also unusual that rupture of such a small aneurysm in the cavernous sinus causes subarachnoid hemorrhage. Embryological development of PTAV and possible mechanism of subarachnoid hemorrhage from the intra-cavernous aneurysm are discussed.