Case Report: Embolization of a cognard type V cavernous sinus dural arteriovenous fistula via occluded Inferior petrosal sinus.

Background: Cavernous sinus dural arteriovenous fistula (CS-DAVF) with cortical venous drainage to the spinal perimedullary veins (Cognard type V) is a rare clinical entity. The treatment becomes particularly challenging when such a case is complicated by occlusion of the inferior petrosal sinus. We report a rare case of Cognard type V cavernous sinus dural arteriovenous fistula (CS-DAVF) embolized with Onyx via the occluded inferior petrosal sinus (IPS). Case description: A 62-year-old woman presented to our hospital with nausea, vomiting and progressive weakness in both lower limbs. Magnetic resonance imaging (MRI) revealed extensive edema of pons and medulla oblongata with flow voids. Cerebral angiography demenstrated a dural arteriovenous fistula (DAVF) in the left cavernous sinus, supplied by the meningohypophyseal trunk and branches of the middle meningeal artery. The fistula drained into the intercavernous sinus and right cavernous sinus, ultimately draining into the spinal perimedullary veins. Transarterial approach was tried first. Onyx-18 was injected into the branches of middle meningeal artery, partially casting the fistula. However, the DAVF was not completely occluded due to residual supply from the meningohypophyseal trunk. The second operation was performed using transvenous approach. The microcatheter was successfully navigated to the fistulous point via the occluded right IPS and the intercavernous sinus. Left cavernous sinus (CS) and intercavernous sinus were casted using Onyx-18 and the DAVF was completely eliminated. Conclusion: We report a Cognard type V CS-DAVF that was embolized with Onyx through an occluded IPS, demonstrating that this technique is a feasible and effective treatment option.