Variant Arteriovenous Fistula of the Superior Sagittal Sinus : Case Report

A 57-year-old male presented with a rare variant of dural arteriovenous fistula, located in the wall of an unobstructed superior sagittal sinus. Drainage occurred through a cortical vein no longer connected to its parent sinus, which filled up a cluster of transmedullary running veins, one of which was the presumed site of hemorrhage. Arterial blood was supplied via the external carotid artery branches. This type of fistula seriously increases the risk of hemorrhage in the patient and therefore requires complete obliteration. Attempts to embolize the fistula failed. The draining vein was isolated and coagulated resulting in permanent occlusion of the fistula. The fistula probably developed through a process of thrombophlebitis and revascularization via arterioles of the vein rather than previous occlusion of the sinus.