重複中大脳動脈瘤の2手術例

Unruptured Saccular Aneurysm at the Origin of the Duplicated Middle Cerebral Artery: Reports of Two Cases and Review of the Literature

Ⅰ．はじめに

　重複中大脳動脈（duplicated middle cerebral artery：DMCA）は前脈絡叢動脈から内頚動脈終末部の間で2本目の中大脳動脈が分岐する血管奇形である．頻度は剖検上0.7～2.9％，血管撮影上0.2～1.5％と比較的稀で，DMCA分岐部に発生した脳動脈瘤は現在まで19例が報告されている^2-18)．今回われわれは同部位に発生した未破裂脳動脈瘤の2手術例を経験した．本疾患についての文献学的考察を加え報告する．

　We report on two rare cases of unruptured saccular aneurysm located at the origin of the duplicated middle cerebral artery. Case 1: On magnetic resonance (MR) angiography, a 56-year-old woman was diagnosed as having an unruptured right middle cerebral artery (MCA) bifurcation aneurysm. Right carotid angiography disclosed a duplicated MCA and four unruptured saccular aneurysms, including the origin of the duplicated MCA. Case 2: A 58-year-old man had a sudden onset of vertigo, and underwent MR imaging. The MR angiography detected a right internal carotid artery (ICA) aneurysm, and the subsequent angiography demonstrated duplication of the right MCA and two intracranial aneurysms; one at the origin of the posterior communicating artery (PcomA), the other at the origin of the duplicated MCA. Each aneurysm was successfully clipped through the transsylvian approach. The postoperative courses were uneventful and both patients were discharged in good condition. There have been only 19 previous reports of the duplicated MCA aneurysm in the literature.