前大脳動脈近位部（A1）動脈瘤の臨床像と治療成績

Aneurysms of the proximal anterior cerebral artery (A1) are rare. We investigated the clinical and angiographical characteristics, and treatment outcomes of A1 aneurysms by reviewing a total of 989 cases of ruptured or unruptured cerebral aneurysms treated with surgical clipping or coil embolization in our department and identified 12 cases of A1 aneurysms (1.2%), including 4 ruptured and 8 unruptured aneurysms. Three of the 4 patients with ruptured aneurysm were Grade IV or V in the classification of the World Federation of Neurosurgical Societies. Five of the 8 cases of unruptured A1 aneurysm were identified during examination for subarachnoid hemorrhage due to ruptured aneurysm at other sites. The A1 aneurysms were located on the proximal segment in 9 cases and projected posteriorly or superiorly in 11 cases. Symptomatic complications occurred in 2 of the 10 cases treated by surgical clipping: cerebral infarction of the genu of internal capsule causing transient motor aphasia in 1 patient, and visual field disturbance due to obstruction of a perforator originating from the A1 in the other patient. Considering the anatomical relationship, any perforator originating from the A1 should be carefully manipulated at surgical clipping.