LAUSR

Here we present a 46-yr-old man with recurrent syncopal episodes thought to be of cardiac origin. He was eventually found to harbor a giant, partially thrombosed, saccular aneurysm arising from the A1/A2 segment of the right anterior cerebral artery with foramen of Monro obstruction and a trapped left-sided ventricular system. An azygous left A2 artery segment supplied both callosomarginal arteries. We performed an in situ side-to-side anastomosis between the distal left azygous anterior cerebral artery and the right pericallosal artery, which was previously supplied by the right A1. The right A1 was clip ligated, and the aneurysm evacuated with an ultrasonic aspirator. Postoperatively, the patient did well with no recurrence of the aneurysm and resolution of his preoperative obstructive hydrocephalus. He continues to be independent >7 yr post surgery. His 6-mo follow-up angiogram revealed a patent bypass.