Transvenous Approaches to Embolization of Dural Arteriovenous Fistulae of the Cavernous Sinus

Dural arteriovenous fistulae of the cavernous sinus (CS) (previously often referred to indirect carotid cavernous fistulas) are rare vascular shunts involving meningeal branches and osseous branches of the external or internal carotid arteries and the CS. They typically present with ocular symptoms including pain, conjunctival injection, and proptosis. Left untreated there may be a risk of vision loss, and fistulas with cortical venous reflux through either the deep or superficial venous system may cause intracranial venous congestion or hemorrhage. Endovascular embolization is the standard treatment, and while transarterial routes may appear possible, transarterial embolization has considerable risks of ischemic complications. Conversely, transvenous routes achieve a high rate of fistula occlusion with a low risk of peri-procedural morbidity. Procedural success depends on identification of the venous outflows from the fistula and localization of the fistulous point, to select the best route of access to the CS, including the inferior petrosal sinus (IPS), intercavernous sinus, or superior ophthalmic vein, among others. Even if the IPS is not visualized, it may be possible to recanalize it to gain access to the CS. Embolization can be performed with a combination of coils, fibered coils, and liquid embolic agents, focusing on occlusion of the fistulous point or blocking high-risk venous outflow pathways. In this review we will highlight procedural pearls and potential pitfalls and our typical approach to these lesions based on illustrative examples.