Transvenous embolization via the pterygoid plexus for a direct carotid-cavernous fistula associated with fibromuscular dysplasia: illustrative case

BACKGROUND: Fibromuscular dysplasia (FMD) is a nonatherosclerotic arteriopathy that increases the risk of intracranial aneurysm and arterial dissection. Direct carotid-cavernous fistula (CCF) associated with FMD is rare, and the endovascular treatment strategy is not well established. OBSERVATIONS: A 52-year-old woman developed a high-flow CCF in the setting of bilateral internal carotid artery FMD. Three-dimensional rotational angiography under balloon test occlusion (BTO) enabled precise localization of the fistula proximal to a cavernous-segment aneurysm. Transvenous selective embolization was achieved through the pterygoid plexus, while the transarterial approach through the FMD-affected ICA was performed safely with a flexible distal access catheter. LESSONS: In FMD-associated CCF, accurate localization of the shunt using BTO and meticulous endovascular technique allowed for safe embolization. The pterygoid plexus proved to be a useful and feasible access route. https://thejns.org/doi/10.3171/CASE26625.