Dural arteriovenous fistulae (DAVF) are rare, abnormal connections between arteries and veins in a protective membrane on the outer layer of the brain and spine, called the dura. These abnormal blood vessels divert blood from the normal paths. If the volume of diverted blood flow is large, tissue downstream may not receive an adequate blood and oxygen supply.
An unusually heavy blood flow also can lead to aneurysms or ruptures in the veins.
This condition can be caused by head trauma, infection, surgery or blood clots in the brain, called thrombosis, or may be a congenital or birth defect.
DAVFs are part of a group of conditions called arteriovenous malformations (AVM). Some fistulas are life-threatening and may cause headaches, seizures or strokes, if they rupture. Others are benign and go undetected until discovered during treatment for other conditions.
At UCSF Medical Center, our Neurovascular Disease and Stroke Center is one of the world's leaders in diagnosing and treating these fistulaes. Our team includes neurologists, neurosurgeons and neuroradiologists who are experts in identifying DAVFs and designing the best possible treatment, including minimally invasive surgical techniques.
The symptoms of dural arteriovenous fistulae (DAVF) can vary widely, depending on the location of the fistulae. Some DAVFs have no symptoms at all and aren't discovered until patients are evaluated for other neurological or vascular conditions.
Some of the common symptoms include:
Headaches: Headaches are among the most common symptoms with all types of DAVFs
Ringing in Ears: An unusual ringing or humming in the ears may be symptom, particularly when the DAVF is near the ear. Some patients hear a pulsating noise caused by blood flow through the fistula.
Stroke-like Symptoms: All types of DAVFs can cause stroke-like symptoms and seizures, if they rupture. Bleeding in the brain is the most serious side effect and can cause permanent disability or death.
Visual Problems: When DAVFs are located near the eye, patients often complain of impaired vision, eye redness and swelling, and sinus congestion.
The following tests may be used to diagnose your dural arteriovenous fistulae (DAVF) and help identify its size, location and blood-flow pattern.
Cerebral Angiography: This X-ray exam shows the structure of blood vessels and is the most important test in diagnosing DAVF. A harmless dye, visible on X-rays, is injected into an artery that supplies blood to the brain. As the dye flows through blood vessels to the brain, it will show any obstructions or leaks.
Computed Tomography (CT) Scan: During this test, X-ray beams are used to create a 3-D image of the brain and may help identify any bleeding or hemorrhage. For more precise images of blood vessels, the cerebral angiography and magnetic resonance angiography (MRA) are performed.
Magnetic Resonance Angiography (MRA): An MRA uses magnetic resonance imaging to create detailed images of blood vessels. Using a strong magnetic field, it generates a 3-D image of the brain to detect, diagnose and aid the treatment of DAVFs and other vascular disorders. In some cases, a dye is injected intravenously.
Treatment for dural arteriovenous fistulae (DAVF) depends on the blood vessels involved. Endovascular techniques, which are minimally invasive procedures that are performed through the blood vessels, have been developed to safely treat DAVFs.
An approach, called embolization, reduces blood flow to the DAVF by obstructing surrounding blood vessels. During this procedure, the DAVF is filled with specially designed coils, glues or spheres that plug the vessels.
Some fistulas can't be completely blocked with embolization and may require surgery to disconnect or close them. In some cases, doctors may try to close the fistula with what's called stereotactic radiosurgery or the Gamma Knife.