A Case of the So-Called Posterior Condylar Canal Dural Arteriovenous Fistula with an Osseous Shunt

OBJECTIVE: The authors describe a case of the so-called dural arteriovenous fistula (DAVF) around the posterior condylar canal (PCC). CASE PRESENTATION: A 71-year-old woman presented with pulse-synchronous bruit on the left side. Conventional DSA demonstrated the following: There were many feeders, including the ascending pharyngeal artery (APA), the occipital artery (OA), and the vertebral artery (VA), to the DAVF around the PCC. Shunt flow from the posterior condylar vein (PCV) drained the suboccipital cavernous sinus (SCS) and sigmoid sinus (SS), and there was venous reflux into the inferior petrosal sinus (IPS). The patient was diagnosed with PCC DAVF and underwent transvenous embolization (TVE) with coils. Intraoperative 3D-rotational angiography (RA) and axially reconstructed images revealed an osseous shunt within the occipital bone adjacent to the PCC. The arteriovenous (AV) shunt and other symptoms disappeared after occluding the drainage route from the osseous shunt to the PCV. CONCLUSION: There are only three previous reports of PCC DAVF, being rare. However, no report clearly described the shunt point of PCC DAVF. 3D-RA and axially reconstructed images were useful to find and treat the shunt point.