頭蓋内巨大動脈瘤の手術成績:瘤内血栓，動脈瘤頸部硬化性変化合併例の検討

Direct surgical management of giant and large intracerebral aneurysms, associated with intraluminal thrombus and/or atherosclerotic thickening of aneurysmal neck

I．はじめに

　巨大脳動脈瘤の自然経過は極めて予後不良で^3,7），神経症状を呈したものを放置することはできない．しかし，顕微鏡下手術が一般化し，手術技術が向上した現在でも，その治療成績は決して満足できるものではない^3）．文献的には術中動脈瘤頸部クリッピングが困難で，母動脈の閉塞術，coating術などを選択せざるを得ない場合が約半数におよぶ^3,6）．クリッピングを施行できた症例でも，手術に伴って発生した脳虚血による術後悪化が少なくない．母血管の一時血流遮断が長時間におよんだための虚血や，クリッピングにより母動脈や分枝動脈の高度狭窄や閉塞を来した結果発生した虚血，さらに動脈瘤内の血栓が剥離して発生した末梢動脈塞栓症などによるものである．大きな動脈瘤でも，特に瘤内血栓が存在したり動脈瘤頸部近傍に動脈硬化巣が存在する場合には，手術時こうした虚血性合併症を如何に防止するかが問題となる．本稿では，このような動脈瘤の手術法，治療成績を報告するとともに，合併症予防法について検討する．

Direct surgical management of giant or large cerebral aneurysms remains one of the most challenging topics in the neurosurgical field. Surgical results have remain-ed unsatisfactory.

We review 22 cases of large or giant aneurysms with intraluminal thrombus and/or atherosclerotic thicken-ing of the aneurysmal neck that have received direct surgical management in our department during the period from 1984 to 1996. As initial symptoms, ten pa-tients presented with mass effect, five with ischemic attack, and three with subarachnoid hemorrhage. Six-teen aneurysms were supratentorial and six were in the posterior fossa. Direct neck clipping was attempted in sixteen cases. Two giant basilar aneurysms among them were clipped under deep hypothermia with car-diac arrest. Simple trapping of the parent artery was performed in three aneurysms and trapping with bypass graft was also carried out in three aneurysms. Ten patients made an excellent clinical recovery. Eleven patients suffered mild to severe disability. One death resulted from brain stem infarction, not directly related with surgical management.

Appropriate preoperative assessment and intraopera-tive management of the associated thrombus arid athero-sclerotic change of the aneurysmal neck are essential for obtaining acceptable surgical results of large or giant cerebral aneurysms.