[A case of pial single-channel cerebral arteriovenous fistula].

A 60-year-old man presented with dizziness, dysarthria, and right hemifacial palsy with sudden onset. Computed tomography scan revealed a small cerebellar hematoma near the left flocculus. Since the site of the hemorrhage was atypical for cerebellar hemorrhages, emergency angiography was performed and revealed a pial single-channel arteriovenous fistula (AVF) in the early arterial phase with drainage into the dilated perimedullary vein. The feeding artery was a peripheral branch of the left anterior inferior cerebellar artery. There were no angiographical findings indicating a nidus or capillary network. The patient underwent left lateral suboccipital craniotomy. A small dilated perimedullary vein and an abnormally red spherical varix were found during the operation. A peripheral branch of the left anterior inferior cerebellar artery was thought to be a feeder because it seemed to be firmly attached to the dilated vein. Based on the operative technique for dural AVFs, electrocoagulation of the varix was performed aiming at obliteration of the fistula. The postoperative angiogram demonstrated the obliteration of the fistula and of the early filling vein. Feeders of cerebral AVF are cerebral arteries. A pial single-channel AVF is defined as a vascular malformation with a single venous channel in communication with one or more arteries with no intervening nidus or vessels. To date, reports in the literature of cerebral arteriovenous fistula have been very few. Its clinical entities such as origin, bleeding rate and the necessity of surgery remain subjects of debate. Here we report our experience and discuss its issues of the treatment we used.