後大脳動脈P2-P3部に発生した血栓化巨大脳動脈瘤の3症例  [in Japanese] Three Cases of Thrombosed Giant Aneurysms of Posterior Cerebral Artery  [in Japanese]

後大脳動脈遠位部に発生する動脈瘤は, fusiform, thrombosed, giant typeが比較的多く, 脳深部に存在し周囲には脳幹などの重要な構造物が存在するため, 治療が困難とされる. 今回われわれは3例の後大脳動脈P2-P3部血栓化動脈瘤を経験し, 症例ごとに異なった方法で治療した. それぞれの治療方法の特徴を検討し報告する. 症例 <症例1> 40歳, 女性. 1993年10月11日, 意識障害にて近医搬入された. CTでSAHと診断され, 右迂回槽に径25mmの占拠性病変を認めた. 脳血管撮影にて右P2血栓化動脈瘤と診断, pterional approachによるneck clippingを行おうとしたが, 瘤が大きく不可能であったため, 後交通動脈のclippingが行われた(Fig. 1). 10月14日, 治療目的に当科転院, 神経学的には軽度の右動眼神経麻痺を認めた. 後交通動脈や瘤近傍より分岐する穿通枝温存のため, 超低体温循環停止下にsubtemporal approachを行った.

As much as 20% of the P2-P3 aneurysms are fusiform, thrombosed, and giant types and since an intimate relationship is present between the cranial nerves and upper brain stem, the surgical approach and dissection of the P2-P3 aneurysm is technically challenging. We present 3 cases of P2-P3 partially thrombosed giant aneurysms treated by means of each procedure. Case I involved a P2 aneurysm, and successful clipping was perfornled using circulatory arrest with profound hypothermia. The perforating branch was preserved. Case 2 involved a P2-P3 aneurysm, and surgical ligation of the P2 proximal to the aneurysm was performed because the parent artery was totally thrombosed. Case 3 involved an aneurysm of the P3 segment, and parent artery occlusion was performed using microcoils after selective P3 balloon occlusion test. All patients had either an excellent, or good outcome. These operative approaches and procedures should be discussed in relation to the anatomy of P2-P3 aneurysms.