Embolization of a Complex Posterior Fossa Dural Arteriovenous Fistula with Precipitating Hydrophobic Injectable Liquid

The angioarchitecture of intracranial dural arteriovenous fistulas (DAVFs) can vary widely, from lesions with a single fistulous connection to those with multiple sites of arteriovenous shunting. [1] Endovascular treatment is currently the first‑line intervention in the management of intracranial DAVFs. A number of embolic agents have been employed for the treatment of DAVFs. Precipitating hydrophobic injectable liquid (PHIL; MicroVention, Tustin, California, USA) is a novel permanent liquid embolic agent which may allow better intravascular penetration than ethylene vinyl alcohol copolymer (Onyx; However, the literature regarding the use of PHIL for the treatment of intracranial vascular malformations is presently very limited. [2‑4] We describe a case of a patient with a complex posterior fossa DAVF which was successfully embolized with PHIL. A 73‑year‑old male presented with 2 weeks of recurrent syncope. Computed tomography angiography showed an infratentorial vascular malformation located posterior to the pineal gland and above the vermis of the cerebellum draining into the straight sinus [Figure 1a and b]. Further evaluation with cerebral angiography revealed a Borden Type III, Cognard Type IV DAVF parasitizing blood supply from multiple branches of the right external carotid artery, including the middle meningeal, superficial temporal, and occipital arteries, as well as the artery of the falx cerebri and left posterior cerebral artery [Figure 1c‑e]. There were two sites of the arteriovenous shunting: One into the vein of Galen (VOG) and straight sinus which comprised the majority of the DAVF's venous drainage and another directly into the superior vermian vein. The shunting from the DAVF was also resulting in pial venous congestion at the surface of the cerebellum. The patient underwent transarterial embolization of the DAVF using PHIL [Figure 2]. The fistulous connection draining into the VOG was occluded from the right middle meningeal artery. However, the straight sinus was inadvertently occluded during this stage of the embolization. The fistulous connection draining into the superior vermian vein was occluded from the right occipital artery. Overall, seven injections of PHIL performed utilizing a total of 1 mL of 30% PHIL and 6 mL of 25% PHIL. The final postembolization angiography demonstrated no evidence of residual arteriovenous shunting, with resolution of the preoperative cerebellar venous congestion. Due to the iatrogenic straight sinus thrombosis, the patient was administered an intravenous heparin infusion for 48 h after the procedure, with the goal of maintaining a therapeutic partial thromboplastin time of 50–70 s. The patient had an uncomplicated postoperative …