脳底動脈閉塞に合併したgrowing up aneurysmの1例

A Case of Growing Up Aneurysms with Occlusion of Basilar Artery

I．はじめに

　脳動脈瘤の成因と増大については，動脈壁の先天性または後天性変化と血流動態が重要な因子であるといわれている^1,2,8-10）．われわれは脳血管バイパス後に発見された未破裂脳底動脈瘤が，半年後に血栓縮小化を示さないためクリッピング術を施行した．さらにその2年後に新たに内頸動脈瘤が発生し，これの破裂によるクモ膜下出血をきたした症例を経験した．この興味ある経過を示した症例について考察を加え報告する．

This is a report of unruptured aneurysms with occlu-sion of the basilar artery.

A 61-year-old female was admitted to our hospital because of dysarthria and numbness of her left face. Angiography revealed occlusion of the basilar artery and severe arteriosclerosis of the bilateral cerebral caro-tid arteries. Pcom was not visualized on bilateral caro-tid angiogram.

These neurological signs were considered to be de-rived from vertebrobasilar insufficiency by occlusion of the basilar artery. Right STA-SCA anatomosis was per-formed to prevent brain stem infarction. Postoperative angiography showed a good filling of both PCA and SCA by collateral circulation via a right STA and an unruptured basilar top aneurysm.

Seven months after the bypass surgery, angiography disclosed that the basilar top aneurysm was visualized clearly, and its size was unchanged. The fact that there was no thrombus formation in the aneurysm was consi-dered to be clue to ticlopidine, and the hemodynamic changes after the bypass surgery were suspected to have increased the intraaneurysmal pressure. Therefore we performed neck clipping of the basilar top aneu-rysm by using a right pterional approach. Two years after the second operation, the patient complained of severe headache and vomiting. CT scan showed sub-arachnoid hemorrhage, and angiography demonstrated a newly developed aneurysm which might have rup-tured on left internal carotid anterior choroidal artery bifurcation. Emergency neck clipping of the second aneurysm was performed, and the patient showed a good postoperative course.

The newly developed second aneurysm might have been caused by severe arteriosclerosis and hypertension in addition to hemodynamic stress.