Cerebral dural arteriovenous fistulas (dAVFs) are characterized by pathologic direct shunts between dural arteries and veins or a venous sinus, with the fistula point or zone located at the dural level. Most often they are found at the wall of the transverse sinus (50%), the cavernous sinus (16%), the superior sagittal sinus (8%), or at the tentorium cerebelli (12%).1 dAVFs are an acquired disease, probably based on (transient) venous thrombosis inducing venous hypertension and subsequently progressive arterialization of the venous vessel wall.
Microvascular connections within the dura might be intrinsic2 and become activated and later hypertrophied, or might be a result of neovascularization3 promoted by angiogenic growth factors. Most practically, dAVFs are classified according to Borden et al4 and Cognard et al,5 with higher grades indicating an increased risk for cerebral hemorrhage. Due to technical innovations like the development of compliant, inflatable occlusion balloons and liquid embolic agents, endovascular embolization has been established as the first-line treatment for dAVFs. Basically, sinus-preserving and sinus-occluding embolization techniques can be distinguished.
The occlusion of a dural sinus, however, carries a risk of venous infarction or hemorrhage. The sinus-preserving technique by transarterial embolization with liquid embolics requires superselective catheterization of arterial feeders to deliver the embolic agent. Onyx (Covidien, Irvine, California) has been widely used as a liquid embolic agent for transarterial embolization,6-8 allowing considerable penetration and casting of the fistula site, but also harboring the risk of accidental embolization of the distal venous system, which may result in the exacerbation of venous hypertension, venous infarction, and/or hemorrhage. Sinus-occluding techniques are still effective treatment options, with a high rate of definite fistula occlusion, but at the cost of a relevant, … more »