Simultaneous transarterial and transvenous contrast injection to reveal the fistulous point in carotid cavernous fistula: illustrative case

BACKGROUND: Access of the cavernous sinus (CS) via venous route from the inferior petrosal sinus (IPS) can sometimes be challenging during the treatment of carotid cavernous fistulas (CCF), largely because of anatomical variations, tortuosity, and/or difficult visualization of IPS given high retrograde flow through the fistulous connection. OBSERVATIONS: A 58-year-old male was transferred to our university hospital center after suspected diagnosis of CCF at another hospital by head computerized tomography-angiogram. His symptoms included three weeks of right eye pain that was later complicated by redness, diplopia, and blurry vision. In a diagnostic angiogram, separate contrast injections from the arterial side via internal carotid artery (ICA) and from the venous side via IPS did not reveal a connection point. Injecting contrast simultaneously from both arterial and venous ends resulted in visualization of a connection point allowing entry into the CS. LESSONS: Technique of simultaneous contrast injection from ICA and internal jugular vein is comparatively simple and saves an operator prolonged time and complexity of approach. In our case, it revealed fistulous point allowing navigation and completing the coiling.