後大脳動脈瘤（P3 Portion）の1経験例

P3 Portion Aneurysm of the Posterior Cerebral Artery:A case report

I．はじめに

　後大脳動脈瘤は，椎骨脳底動脈領域の動脈瘤の15％^14），また全脳動脈瘤の1％^14,21），2.7％^9）など比較的稀といわれる．今回われわれは，後大脳動脈の，後側頭動脈と頭頂後頭動脈の分岐部，即ちP₃部の動脈瘤を経験したので，若干の文献的考察を加えて，これを報告する．

Abstract

A case was reported of surgically treated saccular aneurysm located at the right posterior temporal-parietooccipital artery junction (P₃ portion of PCA) . An aneurysm of this portion is said to he rare, and only 7 cases have been described so far.

A 74-year-old female was transferred to our clinic, af-ter 3, 5 months of sustaining aneurysmal rupture, for surgical treatment. The patient had been treated conser-vatively because of her severe condition in the early stage. She was in nearly apallic state with left hemi-paresis at the time of admission to our clinic. During the acute stage of her illness, moderate hema-toma in the right ambient cistern without hydrocepha-lus, and an aneurysm at P₃ portion of the right post-erior cerebral artery with marked arteriosclerosis were delineated by CT, and by right vertebral angiography respectively. However, in the CT taken 3, 5 months af-ter the onset, moderate hydrocephalus and a low densi-ty area in the right internal capsule were detected.

Aneurysmal neck clipping was performed using the right posterior subtemporal approach, without any de-formity of the parent arteries. Occlusion of the right parietooccipital artery occurred, however, probably on the 2nd postoperative day. Despite the newly developed left homonymous hemianopsia, general condition, in-cluding consciousness level, improved postoperatively particulary after the ventriculo-peritoneal shunt was carried out.