Use of intermediate guide catheters as an adjunct in extracranial embolization to avoid onyx reflux into the anastomotic vasculature. A technical note.

Onyx is a non-adhesive polymer used for embolization of arteriovenous malformations and dural arteriovenous fistulas (DAVFs). The limiting factor for Onyx embolization is usually the amount of microcatheter reflux, which can be safely tolerated. The dual microcatheter technique, compliant balloon use proximally and the use of the dual lumen Scepter balloon have been described to prevent and limit proximal Onyx reflux. We describe the use the Navien 058 intermediate guide catheter to accept the Onyx reflux in its lumen and possibly also serve as a mechanical barrier to avoid reflux into the anastomotic channel connecting the occipital artery to the vertebral artery during DAVF embolization via the occipital artery. Complete embolization of the DAVF was achieved using the lumen of the Navien catheter to accept aggressive Onyx reflux. Complete cure of the DAVF was obtained with Onyx cast filling the entire venous pouch. Besides providing distal access support, intermediate guide catheters can also prevent embolic material reflux by accepting reflux into the lumen and providing a mechanical barrier.