Dural arteriovenous fistula (dAVF)
What is it?
They represent a direct connection between arteries and veins without capillary blood flow, but in contrast to arteriovenous malformations, they are located in the dura mater, connecting to the cerebral veins (venous sinuses of the dura mater).
The lack of capillary circulation, which usually reduces the pressure between the arteries and veins, creates very high pressure in the cerebral veins, making it difficult for blood to drain from the brain.
They can also develop in the spinal cord.
Causes and risk factors
These are rare diseases. They account for about 10-15% of cerebral arteriovenous malformations.
Unlike arteriovenous malformations, which are congenital, dural fistulas are mostly acquired as a result of cerebral vein thrombosis due to infections, trauma, or surgical procedures.
However, it is not always possible to establish the exact cause.
Which are the symptoms?
An increase in arterial flow, resulting from a lack of capillaries, may manifest as a sensation of “noise” synchronous with the heartbeat, which is heard in the ear.
Increased venous pressure, if it affects a limited area of the brain, can cause cerebral hemorrhage or focal neurological deficits. If the venous outflow obstruction affects the entire brain, there can be progressive deterioration of all brain functions (dementia).
Increased pressure can also manifest itself as decreased vision due to damage to the optic nerves (papilloedema).
Finally, if fistulas involve the spinal cord, they may manifest as progressive impairment of the ability to move, impaired sensation and sphincter control.
Dural fistulas are difficult to diagnose: complaints are often vague and nonspecific.
How is it diagnosed?
With magnetic resonance imaging, a suspicion of this disease may arise, but the only study to obtain an accurate diagnosis is cerebral angiography, which examines the cerebral arterial vessels in detail.
Suggested exams
How is it treated?
Some types do not require surgical treatment because there is no risk of cerebral hemorrhage. Others require treatment, which may be surgical, endovascular, or a combination of both.
The optimal treatment is chosen on the basis of the fistula and its location, with a joint evaluation by surgeons and neuroradiologists.
Where do we treat it?
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