Dural Arteriovenous Fistula

A dural arteriovenous fistula (DAVF) is an abnormal connection between the arteries that normally supply the covering of the brain and veins. Usually develops in adult life and can cause symptoms of pulsitile noise, headache, hemorrhage, stroke, or seizure. The treatment of AVFs can include surgery, embolization, or radiosurgery.

A dural arteriovenous fistula results when the blood vessels that normally supply the scalp and coverings of the brain (dura mater) have an abnormal direct connection to veins that drain the brain. This represents a short circuit that results in abnormal high flow within the brain veins. There are two main types of dural arterio-venous fistulas depending on whether or not the short circuit results in backwards flow and congestion into veins that drain brain tissue. The presence or absence of this backflow into normal veins is determined by doing a test call an angiogram where a tube called a catheter is inserted into the groin and threaded upstream of the artery in question. X-ray dye is injected through the catheter and x-ray images are recorded. If there is no backwards flow into the brain veins, then there is virtually no risk of stroke or bleeding into the brain. However, the risk of bleeding, stroke, or death is high if backflow into normal brain veins is seen on the angiogram.

If there is no backflow of blood into the brain veins, then treatment is generally not recommended because the risk of stroke or bleed is low. Treatment of fistulas with backflow into the brain veins is highly recommended because of the relatively high risk of stroke, bleed, or death. There are two main ways of treating these fistulas. Surgery can be performed where the surgeon makes an incision and disconnects the abnormal short circuit. Another method of treatment is an embolization which is a procedure in which the doctor places a tiny catheter into the site of short circuit and blocks it by injecting metal coils, liquid adhesives, or tiny plastic particles.

See Dural Arterio-Venous Embolization Example

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