Direct Carotid-Cavernous Fistula Associated with Fibromuscular Dysplasia: Balloon-Assisted Internal Carotid Artery Protection and Transvenous Cavernous Sinus Occlusion Using Coils and Onyx

Abstract

Direct carotid-cavernous fistulas (CCFs), or Barrow Type A CCFs, are most commonly seen after head trauma. Direct CCFs may also arise owing to an iatrogenic injury to the cavernous internal carotid artery (ICA) inflicted during intracranial surgery or endovascular procedures, after rupture of a cavernous carotid aneurysm, or after minor trauma in patients with a genetic predisposition or defective cavernous ICA wall (e.g., Ehlers-Danlos syndrome or fibromuscular dysplasia). Our patient was a 67-year-old female with an unremarkable medical past except for hypertension and obesity, who presented with sudden onset right orbital pain, proptosis, conjunctival chemosis, blurred vision, diplopia, and high-pitched pulsating tinnitus. She was admitted to the emergency room where ophthalmological and neurological evaluations were performed. Pulsatile exophthalmos and chemosis were remarkable and considered pathognomonic of CCF. Head CT and CTA showed orbital congestion, venous engorgement with an enlarged superior ophthalmic vein, and bulging of the cavernous sinus. Diagnostic angiography of the right ICA revealed rapid arteriovenous shunting from the ICA to the cavernous sinus and stealing hemispheric arterial supply and retrograde flow from the cavernous sinus to engorged petrous, ophthalmic, and Sylvian veins. No carotid-cavernous aneurysm was detected, but there were subtle signs of arterial fibromuscular dysplasia. The patient underwent endovascular embolization employing transpetrosal sinus cavernous coiling and Onyx injection to exclude the CCF under balloon-assisted ICA occlusion and protection. Immediate postembolization diagnostic angiography confirmed restitution of the antegrade carotid brain supply and the complete disconnection of the arteriovenous shunting. The patient evolved satisfactorily with remission of ophthalmological and neurological clinical signs immediately after the procedure. Her angiographic follow-up after 18 months confirmed normalized ICA transit, exclusion of the cavernous sinus, and no remnant of the CCF. This case illustrates the embolization of a type A CCF via transvenous petrosal access aided by balloon-assisted arterial control.