2歳男児の破裂中大脳動脈解離性動脈瘤の1手術例

A Ruptured Middle Cerebral Artery Dissecting Aneurysm Operation in a 2-Year-Old Boy

Ⅰ．はじめに

　脳動脈瘤破裂によるくも膜下出血（subarachnoid hemorrhage：SAH）は成人に多く，小児期に発症することは少ない．また，解離性脳動脈瘤は椎骨脳底動脈系に多いとされている．今回われわれは，2歳の幼児の中大脳動脈M3部に発生した解離性脳動脈瘤の治療と再発を経験した．治療方法について文献的考察を加えて報告する．

　We report the case of a ruptured dissecting aneurysm in an infant. A 2-year-old boy suffered sudden headache and nausea. CT scan revealed a subarachnoid hemorrhage, and digital subtraction angiography（DSA）revealed a dissecting aneurysm（3.9mm）at a branch of the right middle cerebral artery（MCA). Eight days after onset, carotid angiography revealed enlargement of the aneurysm（up to 6.8 mm). Right frontotemporal craniotomy and aneurysm trapping with STA-MCA bypass was performed.

　Two years and two months later, the aneurysm recurred as assessed by magnetic resonance angiography（MRA). DSA revealed the recurrence of the aneurysm（7.8mm）proximal to the previous aneurysm and displayed development of collateral flow through leptomeningeal anastomosis between the branches of the MCA. During the second operation, the aneurysm extended to the artery branch proximal to the previous trapping. Parent artery occlusion without bypass was performed. Postoperative DSA revealed collateral flows through leptomeningeal anastomosis between the branch of the MCA and the branch of anterior cerebral artery. At the 3-year follow-up period, abnormal findings on MRI did not appear and he was healthy without any neurologic abnormalities.