Dural arteriovenous fistula (DAVF) is a vascular abnormality characterized by arteriovenous shunting located within the folds of the dura mater. It receives arterial blood supply from branches of the internal carotid artery, external carotid artery, or vertebral artery. In 8% of cases, multiple fistulas have been identified. Common locations include the transverse/sigmoid sinus, tentorium/petrous region, anterior cranial fossa/ethmoid sinus, middle cranial fossa/sylvian fissure, cavernous sinus (carotid-cavernous fistula), superior sagittal sinus, and foramen magnum region.
Most DAVFs are acquired conditions, often associated with dural venous sinus thrombosis, trauma, inflammation, pregnancy, or childbirth. The majority of cases occur in women (61%–66%), typically presenting between 40 and 50 years of age.
Clinical Manifestations
The clinical manifestations include pulsatile tinnitus, intracranial bruit, headache, elevated intracranial pressure, seizures, cranial nerve palsies, focal neurological deficits, and intracranial hemorrhage.
Diagnosis
Head CT and MRI scans can reveal secondary signs of increased intracranial pressure, cerebral edema, intracranial hemorrhage, and hydrocephalus. However, normal findings on CT and MRI imaging do not exclude the diagnosis of DAVF.
Digital subtraction angiography (DSA) is the most reliable method for confirming the diagnosis. DAVFs are richly supplied with blood, necessitating six-vessel cerebral angiography, which includes imaging of both internal carotid arteries, both external carotid arteries and their branches, and both vertebral arteries. In some cases, additional imaging of branches such as the thyrocervical trunk and costocervical trunk may be required to avoid missing a diagnosis. Each angiographic study should include the venous phase to assess the intracranial venous drainage and the status of the venous sinuses.
Treatment
Approximately half of low-flow carotid-cavernous fistulas (CCFs) may spontaneously thrombose and close without intervention. For cases with a history of hemorrhage, intolerable intracranial vascular bruit, progressive neurological deficits, or symptoms of local compression and elevated intracranial pressure, endovascular treatment is indicated. Detachable latex balloons, coils, or other embolization materials are used to occlude the fistula.