対側の内頸動脈後交通動脈分岐部動脈瘤破裂10年後に動脈瘤化，出血したinfundibular dilatationの1例

A Case of Infundibular Dilatation Developed into an Aneurysm and Rupturing after the Rupture of an Aneurysm 10 Years Ago

Ⅰ．は じ め に

　Infundibular dilatationは内頸動脈後交通動脈分岐部で，①直径が3mm以下であること，②先端より後交通動脈が出ていることと定義され^11,14)，脳血管撮影時に7～25%にみられるとされている^9,10)．Infundibular dilatationの剖検例において，壁は正常で破裂の危険性は極めて少ないとするものがある一方⁶⁾，破裂する例も存在するという報告もあり^4,7-9,11)，一定の見解はない．今回，左内頸動脈後交通動脈分岐部動脈瘤破裂時に対側の同部位に確認されたinfundibular dilatationが，10年後には動脈瘤化，破裂し，治療した例を経験したため，文献的考察を加えて報告する．

A 44-year-old female with subarachnoid hemorrhage caused by the left internal carotid-posterior communicating artery aneurysm rupture was presented. At that time,carotid angiography showed the left internal carotid-posterior communicating artery aneurysm and the right internal carotid-posterior communicating artery portion infundibular dilatation. Neck clipping for left internal carotid-posterior communicating artery aneurysm was done and she was discharged from our hospital without neurological deficit.

　After 10 years,she suffered a second subarachnoid hemorrhage. Carotid angiography demonstrated the right internal carotid-posterior communicating artery aneurysm developed from the opposite infundibular dilatation.

　Emergency clipping was performed with three Sugita fenestration clips,because that aneurysm had a very wide neck.

　We should examine the internal carotid-posterior communicating artery infundibular dilatation with opposite side aneurysms in young females carefully and serially.