上小脳動脈marginal branchに発生した破裂動脈瘤の1例

Ruptured Aneurysm of the Marginal Branch of the Superior Cerebellar Artery : case report

I．はじめに

　セルジンガー法による選択的脳血管撮影が一般化して後頭蓋窩動脈瘤の検出率が増加したとはいえ，各小脳動脈末梢部の動脈瘤はまれである．著者らは上小脳動脈瘤のなかでもさらに頻度の少ない，外側皮質枝であるmarginal branchに発生してくも膜下出血で発症した症例を経験した．治療上の問題点を文献的考察を含めて報告する．

The authors report a rare case of a ruptured aneurysm arising from the marginal branch of the left supe-rior cerebellar artery. At the first retrosigmoid craniectomy carried out on the clay of hospitalization, theclip was wrongly placed on the anterior inferior cerebellar artery (AICA). The unanticipated accident wasdue to incomplete dissection of a thick and severely adhered subarachnoid clot and the mistake was madebecause the course of the marginal artery was similar to that of the AICA. At the second operation under-gone 1 week later, the aneurysm was easily and successfully clipped. After ventriculoperitoneal shunting,the patient returned to normal except for left hearing loss. The authors suppose that delayed surgerywould be beneficial as a rule for ruptured aneurysms of the peripheral branch of the cerebellar arteries notonly because dissection is easier but also because the risk of rebleeding and vasospasm are reported to below in such aneurysms.