遠位部脳底動脈開窓部動脈瘤の1例

Saccular aneurysm associated with fenestration of the distal segment of basilar artery

I．はじめに

　脳血管撮影上0.23-0.6％に脳底動脈の窓形成がみられるが^10,17），椎骨—脳底動脈移行部が脳底動脈窓形成全体の73％を占める^19）．また椎骨—脳底動脈移行部動脈瘤に窓形成が合併することは35.5％もあり^4），動脈瘤形成と窓形成との関連性が考えられている^3-5,19,20）．だが脳底動脈遠位部の窓形成は脳底動脈窓形成全体の9％を占めるに過ぎず^19），まして嚢状動脈瘤を伴った窓形成は極めて稀であり，現在のところ本例を含めて3例の報告しかない^1,5）．

　脳底動脈遠位部の窓形成に動脈瘤を伴った稀な症例とその手術方法につき検討を加え報告する．

A 32-year-old man who presented with subarachnoid hemorrhage was found to have a saccular aneurysm arising from the proximal end of the fenestration formed at the distal third of basilar artery. The aneurysm dome was directed anteriorly and measured 3mm in diameter. It was successfully clipped via sub-temporal transtentorial approach and the patient re-turned to his previous job.

Basilar artery fenestration is angiographically found in 0.23-0.6%. The fenestration is most frequently lo-cated in the proximal basilar trunk close to the verte-bro-basilar junction.

In this report a rare case with an aneurysm associ-ated with fenestration in the distal part of the basilar artery will be presented.