Subarachnoid hemorrhage caused by dural arteriovenous fistula of the sphenobasal sinus--case report.

A 59-year-old woman presented with a rare middle fossa dural arteriovenous fistula (AVF) unrelated to the cavernous sinus manifesting only as subarachnoid hemorrhage. Angiography revealed shunts between the meningeal branches of both the internal and external carotid arteries and the sphenobasal sinus. The AVF drained into the superficial middle cerebral vein (SMCV) which had a varix and an anastomosis to a superior cerebral vein. The arterial supply vessels were eliminated surgically and the sinus was excised. Bleeding did not recur and there was no venous infarction. Dural AVF of the sphenoparietal sinus is associated with pulsatile exophthalmos and dural AVF of the sphenopetrosal sinus with tinnitus, but dural AVF of the sphenobasal sinus has no obvious symptom. Simple interruption of the SMCV at the penetration of the arachnoid membrane was possible because of the absence of a draining vessel to preserve AVF patency, but the arteries were eliminated in this patient to prevent formation of another AVF.