Bihemispheric ACA A1-A2 junctionに発生した動脈瘤破裂によるくも膜下出血の1例

Ruptured Aneurysm of Bihemispheric Anterior Cerebral Artery A1-A2 junction:A Case Report

Ⅰ．はじめに

　前大脳動脈（anterior cerebral artery：ACA）のanomalyはazygos variant, bihemispheric ACA, triple A2（accessory ACA：AccACA）などが知られており，臨床上しばしば見受けられる．Azygos variantや，bihemispheic ACAなどに合併したACA遠位部動脈瘤によるくも膜下出血（subarachnoid hemorrhage：SAH）症例は文献上散見するが，bihemispheric ACAのA1-A2 junctionに発生した動脈瘤によるSAH症例は，われわれが渉猟し得た限りでは見当たらない．今回われわれはbihemispheic ACA A1-A2 junctionに発生した動脈瘤によるSAH症例を経験したので，文献的考察をまじえて報告する．

　We report a rare case with a ruptured aneurysm of the bihemispheric anterior cerebral artery（ACA), a rare anomaly of the ACA. A 50-year-old female experienced a sudden onset of severe posterior cervical pain. CT revealed diffuse subarachnoid hemorrhage（SAH）and intra cerebral hemorrhage of the left rectal gyrus. Cerebral angiography showed the left bihemispheric ACA and hypoplasia of the right ACA. A saccular aneurysm was indicated at the A1-A2 junction of the left bihemispheric ACA. A neck clipping was performed completely through the right transsylvian approach. There are several reports of an aneurysm with bihemispheric ACA, but all cases are distal ACA aneurysms. In this case, the aneurysm was proximal to the bihemispheric ACA and such aneurysms have not been reported.