Dural AVM

CTA: posterior fossa vascular malformation. Prominant subarchnoid venous varices near the torculum (red) and menigeal arterial branches (blue)

A dural arteriovenous malformation is an abnormal connection between a meningeal artery and a meningeal vein or dural venous sinus.


Type I dural arteriovenous malformation are suppied by meningeal arteries and drain into a meningeal vein or dural venous sinus. The flow within the draining vein or venous sinus is anterograde.


The high pressure within a Type II dural AV malformation causes blood to flow in a retrograde fashion into subarachnoid veins which normally drain into the sinus. Typically this is because the sinus has outflow obstruction. Such draining veins form venous varices or aneurysms which can bleed. Type II  malformation need to be treated to prevent hemorrhage. The treatment may involve embolization of the draining sinus as well as clipping or embolization of the draining veins.


Type III dural AV  malformation  drain directly into subarachnoid veins. These veins can form aneurysms and bleed. Type III dural malformation need to be treated to prevent hemorrhage. Treatment can be as simple as clipping the draining vein at the site of the dural sinus. If treatment involves embolization, it will only typically be effective if the glue traverses the actual fistula and enters, at least slightly, the draining vein.