Transchoroidal-fissure approachを用いて急性期クリッピング術を行った破裂後大脳動脈瘤（P2）の1例

A Case of Clipping of a Ruptured Aneurysm of the Posterior Cerebral Artery （P2）via the Transchoroidal-fissure Approach

Ⅰ．は じ め に

　後大脳動脈（P2）動脈瘤は発生部位としては稀であり，脳神経外科医にとって遭遇する機会が少なく，治療困難な動脈瘤の1つである¹¹⁾．同部位の動脈瘤への到達方法として，過去の報告ではsubtemporal approachが多く用いられているが，側頭葉圧排が過度になる傾向もあり，transchoroidal-fissure approachの有用性を述べている報告も散見される¹¹⁾．しかし，この部の動脈瘤は脳深部に位置しており，解剖学的に複雑であるため，脳血管撮影写真だけでは動脈瘤の形状，および周囲組織との位置関係を把握することが困難である．今回われわれは，重症のくも膜下出血（subarachnoid hemorrhage：SAH）で発症し，left IC-PC aneurysm（AN）を合併したleft P2 ruptured ANの1例を経験し，3D-digital subtraction angiography（DSA）により動脈瘤の形状の詳細な把握を行った後，left pterional approachでIC-PC ANを確認した後に，transchoroidal-fissure approachを用いて急性期手術を行い，良好な経過を得たので報告する．

A 59-year-old female was found to be drawn in a swimming pool and transferred to our hospital. The patient was comatose on admission (Hunt ＆ Kosnk: Grade Ⅳ). Computed tomography (CT) showed diffuse subarachnoid hemorrhage (SAH) with thick hematoma in the left ambient cistern. Conventional cerebral angiography and 3D-digital subtraction angiography revealed aneurysms （ANs） of the left posterior cerebral artery (P2),and bifurcation of the left internal carotid and posterior communicating arteries (IC-PC). Successful neck clipping was performed the same day through the temporal horn via the insula for ruptured P2 AN,and the non-ruptured IC-PC AN was also obliterated using a pterional approach. Postoperative course was uneventful except for initial disturbance of consciousness and aphasia. The patient was discharged with no neurological deficit 1 month after surgery.

　This approach may be preferable in cases involving high positioned PCA AN in the ambient cistern,particularly in the acute phase of severe SAH,as the brain is protected from the detrimental effects of strong temporal retraction and a wider working space is provided.