STAのinterposition graftを用いたSTA-ACAバイパスおよびendovascular trappingを行った前大脳動脈解離によるくも膜下出血の1例

A Case of STA-A3 Bypass with a STA Interposition Graft and Endovascular Trapping for a Ruptured A2 Dissecting Aneurysm

Ⅰ．はじめに

　近年，非外傷性頭蓋内動脈解離の報告は増加しており脳卒中の原因として広く認知されてきている．その中で前大脳動脈解離の報告は比較的稀であり，治療方針や手術方法についても確立されていない．特に前大脳動脈（anterior cerebral artery:ACA）の灌流領域が脳梗塞に至っていない場合には血行再建も必要となり，治療がより複雑になると思われる．

　われわれはACA A2部の解離性動脈瘤破裂によるくも膜下出血の1例を経験し，外科手術と血管内治療による複合的治療を行ったので報告する．

　A 57-year-old man presented with sudden-onset consciousness disturbance. He had a 10-year history of a subarachnoid hemorrhage（SAH）caused by a ruptured aneurysm in the right middle cerebral artery, and had undergone aneurysmal clipping. He could perform all his daily life activities independently. Computed tomography showed diffuse SAH with intraventricular hemorrhage. Digital subtraction angiography（DSA）demonstrated mild fusiform dilatation of the left A2 portion of the left anterior cerebral artery（ACA）and the terminal portion of the left internal carotid artery with no sign of right middle cerebral artery（MCA）aneurysm recurrence. We could not identify the bleeding lesion at that time；therefore, conservative treatment was selected in the acute phase. Fourteen days later, repeated DSA showed fusiform dilatation of the left A2 portion leading to a diagnosis of ACA dissection. We initially performed superficial temporal artery（STA)-ACA anastomosis and secondary internal trapping with detachable coils in the operating room. Postoperative DSA revealed complete obliteration of the dissection and parent artery. Endovascular treatment with STA-ACA bypass is a safe and effective alternative for the treatment of ACA dissection.