doi: 101136/bcr-2013-010651 To cite: Takemoto K,

The anterior condylar confluence (ACC) is a small complex venous structure located medial to the jugular vein and adjacent to the hypoglossal canal. To our knowledge, this is the first report of transvenous Onyx embolization for ACC dural arteriovenous fistula (DAVF). Three patients with ACC DAVF were treated using the Onyx liquid embolic agent with or without detachable coils. Complete angiographic obliteration of the fistulas was achieved in all cases without permanent lower cranial neuropathy. This report suggests that the controlled penetration of Onyx is advantageous in order to obliterate ACC DAVFs with a small amount of embolic material. BACKGROUND An anterior condylar confluence (ACC) dural arteriovenous fistula (DAVF) is a rare lesion (rate reported as 3.6 % of all DAVFs)1 but, up to a decade ago, some cases of this disease were reported under other names (eg, DAVF involving the hypoglossal canal, DAVF of the anterior con-dylar vein) or as the adjacent fistulas (eg, DAVF involving the inferior petrosal sinus, DAVF of the marginal sinus (MS)) due to the complicated venous structure at the craniocervical junction (figure 1).2–5 Recently, based on the contributions of high-resolution diagnostic tools and several arti-cles about the detailed anatomy of this location, the terminology has been almost harmonized and suc-cessful endovascular treatments based on this accur-ate anatomical knowledge are being developed. At present, most ACC DAVFs can be suessfully treated with transvenous coil embolization.1–3 6–11 However, it is not always possible to achieve com-plete obliteration using only coils in such a restricted small complex compartment without migrating into adjacent vital venous structures including the internal jugular vein, and compres-sing the hypoglossal nerve.1 3 9 Especially in high-flow lesions, the use of liquid embolic material such as Onyx (Covidien/ev3 Neuromuscular