Access-route Visualization Using Ultrasonography and CT Angiography to Predict the Feasibility of Transvenous Embolization via the Facial Vein for Cavernous Sinus Dural Arteriovenous Fistulas

OBJECTIVE: Transvenous embolization (TVE) is an effective treatment for cavernous sinus dural arteriovenous fistulas (CS-DAVFs). The facial vein (FV) can be used as an access route for TVE when a trans-inferior petrosal sinus (IPS) approach is difficult. We evaluated the usefulness of combining ultrasonography (US) with computed tomography angiography (CTA) for confirming that the FV is a suitable access route for treating CS-DAVFs. METHODS: Trans-FV TVE was planned for five CS-DAVF patients in whom the shunt point was located in the posterior compartment of the CS and anterior venous drainage predominantly occurred via the superior ophthalmic vein (SOV). The anterior drainage route was examined with CTA and US. We reviewed the relationships between preoperative CTA/US findings and the accessibility of CS-DAVFs via the FV. RESULTS: The periorbital and perimandibular drainage pathways were clearly more visible on US than on CTA, and the cervical and thoracic drainage pathways were more visible on CTA than on digital subtraction angiography (DSA). CS-DAVFs were accessible via the FV when (1) the entire drainage pathway could be confirmed on CTA and US, (2) the periorbital and perimandibular pathways were unclear on CTA, but could be confirmed on US, or (3) the FV pathway drained into the internal jugular vein (IJV) or external jugular vein (EJV). On the other hand, TVE was challenging to perform via the FV when (1) the periorbital pathway was unclear on CTA and US, (2) the FV pathway drained into the brachiocephalic vein, or (3) the SOV thrombosed intraoperatively. In all five patients, TVE for CS-DAVFs performed via the FV or IPS was successful. CONCLUSION: CTA and US are useful for confirming the anterior access route for trans-FV TVE for CS-DAVFs and predicting the feasibility of such treatment. Our findings suggest that CS-DAVFs can be accessed via the FV if the periorbital drainage pathway can be confirmed on US, even if the pathway is unclear on CTA.