Introduction Transarterial embolization with Onyx is a relatively safe and increasingly common method of treating cranial dural arteriovenous fistulas (DAVF) and arteriovenous malformations (AVM). Cranial neuropathy resulting from this procedure has been reported.

Case reports Three case histories are presented in two patients treated for a DAVF and an AVM near the skull base with heavily parasitized supply from external carotid artery branches. Transarterial embolization resulted in transient cranial neuropathies including two cases of lower facial nerve palsy and one case of trigeminal nerve mandibular segment (V3) neuralgia which resolved spontaneously over a few months. Treatment of the DAVF and AVM was otherwise successful.

Discussion The most common cranial neuropathies following transarterial Onyx embolization procedures are facial nerve palsy and V3 neuralgia. The middle meningeal and internal maxillary arteries are common conduits used in dural-based and facial arteriovenous shunt lesions and are in proximity to the facial nerve and maxillary segment of the trigeminal nerve as they exit the skull base. Based on their relative frequency and anatomic proximity, it is surmised that these facial neuropathies are traction-type injuries related to microcatheter extraction from the Onyx cast.

Conclusions Cranial neuropathies, specifically facial nerve palsy and V3 neuralgia, following transarterial Onyx embolizations are probably axonotmetic traction injuries related to microcatheter extraction. These appear to be self-limiting and resolve over a few months.