A dural arteriovenous fistula (DAVF) is an abnormal connection of arteries and veins in the dura, the covering of the brain or spinal cord. A DAVF may also be referred to as a dural arteriovenous malformation (DAVM). DAVFs are rare and typically develop in middle aged or older people, but they can occur at any age, or be present from birth. People who have diabetes, cancer, AIDS, Crohn’s disease, inflammatory bowel disease, or other disease that affect the immune system or gastrointestinal organs have an increased risk of developing fistulae.
People who develop a dural arteriovenous fistula in the head may hear a whooshing sound or ringing in the ears. Other symptoms include swelling of the eyes, headaches, and weakness. Some symptoms of DAVFs in the brain covering are very similar to stroke symptoms, including numbness, paralysis on one side of the body, and problems with balance, memory, and vision. DAVFs in the spine may cause decreased function in the legs, bowels, or bladder. Spinal DAVF symptoms are usually progressive, meaning they start out mild and get worse over time.
A DAVF can cause serious medical problems and may be fatal in some cases. Brain hemorrhage and seizures are the most serious complications of a dural arteriovenous fistula in the brain covering. Neurological problems, blindness, and progressively worsening weakness and incontinence are also possible long-term problems. Many of these issues can be eliminated or minimized with prompt diagnosis and proper treatment.
Doctors use a variety of tests to diagnose DAVFs in patients who display symptoms of a fistula. A bruit, an abnormal sound heard when listening to an artery with a stethoscope, is often the first indication to a doctor that a patient may have a DAVF. If other, more common medical conditions have been ruled out, the doctor will likely order magnetic resonance imaging (MRI) or angiography tests, which allow doctors to see the inside of the blood vessels, to confirm the diagnosis.
An operation performed by a specialized neurosurgeon is usually necessary to treat a dural arteriovenous fistula. Open surgery involves the surgeon exposing the brain or spinal covering, and physically disconnecting the DAVF from the dura to minimize the risk of further complications. Endovascular surgery involves running a small tube, called a catheter, into the arteries around the DAVF to deposit a resin material, which destroys the fistula as much as possible. This procedure may be done on its own, or may be done as a precursor to open surgery to make the procedure easier.