Background and purpose Cognard type IV anterior cranial fossa dural arteriovenous fistulas (DAVFs) are rare lesions with a high risk of intracranial hemorrhage. We present our experience with the use of Onyx via the arterial route in these aggressive lesions.

Materials and methods Between October 2009 and October 2011, six consecutive patients diagnosed with Cognard type IV anterior cranial fossa DAVFs were treated transarterially with Onyx in our department. All patients were male; mean age was 55 years (range 38–68). Four patients presented with intracranial hemorrhage as the initial manifestation; one patient presented with seizures at the time of diagnosis and experienced intracranial hemorrhage during the antiepileptic therapy; and the other patient was asymptomatic.

Results In five patients, complete obliteration was achieved with transarterial Onyx injection in a single treatment session; in the remaining patient, subtotal occlusion was achieved and gamma knife treatment was followed. The average time of injection was 19 min (range 5–28) for every pedicle catheterized and the average amount of Onyx was 3.2 ml (range 0.4–6.3) for each lesion. All patients recovered uneventfully after embolization. No mortality or permanent morbidity was observed in this series. Follow-up digital subtraction or MR angiography confirmed durable obliteration of the fistulas in five cured cases. No patients suffered intracranial hemorrhage during the follow-up period.

Conclusions In this small series, our experience with the use of Onyx for arterial embolization of Cognard type IV DAVFs is encouraging, with durable complete cure in most lesions without severe complications.