Intra-arterial onyx embolisation of sphenobasilar sinus fistula using pressure cooker technique: case report and review of the literature.

Dural arterio-venous fistulas of the middle cranial fossa may occur within the dura of lesser or greater sphenoid wings. Lesser sphenoid wing fistulas rarely recruit cortical venous drainage and mostly drain in the cavernous sinus. On the other hand, greater sphenoid wing dural fistulas, also known as paracavernous fistulas or sphenobasilar and sphenopetrosal sinus fistulas, are much more notorious as they almost always connect with the superficial middle cerebral vein resulting in secondary cortical venous reflux and varix formation. Curative transarterial or transvenous endovascular embolisation of fistulous connection is the primary therapeutic strategy, particularly using onyx via the transarterial approach. In the present case we describe a 62-year-old man who presented with significant subarachnoid haemorrhage, intraparenchymal and intra-ventricular bleed. Digital subtraction angiography showed a middle cranial fossa dural arteriovenous fistula in the region of the sphenobasilar sinus with cortical venous reflux and varix formation. The patient underwent successful transarterial endovascular embolisation with complete elimination of the fistula using onyx 34, onyx 18, squid 12 and a Scepter XC balloon using the pressure cooker technique. We also report the development of facial nerve palsy due to inadvertent reflux of onyx in the petrosal branch of the middle meningeal artery.