Transarterial Onyx embolization with targeted balloon-assisted sinus protection for treatment of dural arteriovenous fistula of the lateral tentorial sinus

We present a unique sinus protection technique that uses a short-length supercompliant balloon during the transarterial Onyx embolization for the dural arteriovenous fistula (DAVF) of the lateral tentorial sinus. With this technique, we temporarily change the Borden classification from type II to type III, avoiding venous compromise and reducing the risk of Onyx migration into the patent sinus. A 54-year-old man presented with left persistent tinnitus of 4 months’ duration. Cerebral angiography revealed a Borden type II left lateral tentorial sinus-DAVF associated with retrograde cortical venous reflux draining into the vein of Labbé. In the venous phase, the ipsilateral transverse-sigmoid sinus was recognized as a functional sinus and the posterior temporal vein drained into the transverse sinus near the drainage channel. We planned to perform transarterial Onyx embolization using a short-length sinus protection balloon to protect against Onyx migration. During transarterial Onyx injection, a 7 × 7-mm HyperForm balloon was navigated into the affected sinus and positioned to cover the drainage channel from the shunt. After confirming the change in Borden classification with angiography, transarterial Onyx embolization was performed via the middle meningeal artery. This procedure resulted in complete obliteration of the fistula with good patency of both the transverse-sigmoid sinus and neighboring normal cortical veins. No procedure-related complications were observed and the patient remained free of recurrence during the 24-month follow-up period. Short-length balloon-protected Onyx embolization can be safe and effective for the treatment of Borden type II DAVF. Keywords: HyperForm balloon, Lateral tentorial sinus, Onyx, Sinus protection, Tentorial dural arteriovenous fistula