Traumatic direct caroticocavernous fistula

Case contributed by Henry Knipe

Presentation

Fall with headstrike. Right periorbital swelling.

Patient Data

Age: 75 years
Gender: Male

Thin left cerebral convexity subdural hematoma. No midline shift. 

Fracture through the lateral wall and roof of the right sphenoid sinus, extending to the middle cranial fossa and posterior aspect of the anterior cranial fossa floor. These are in close relation to the right internal carotid artery.

Right periorbital hematoma with hyperdense focus (probably a foreign body). Undisplaced fracture through the anterior wall of the right maxillary sinus with a small volume of hematoma in the right maxillary sinus. Undisplaced fracture through the right lateral orbital wall with minimal amount of orbital gas. Right proptosis but no large orbital hematoma.

Early filling of the right superior orbital vein, the vein between the orbit and the cavernous appears narrowed. Also early filling venous structures inferiorly. Asymmetric opacification of the right cavernous sinus. No ICA dissection identified. Relative proptosis of the right eye with left enophthalmos.

Image quality degraded by motion artifact. Arteriovenous shunting from the right cavernous internal carotid artery into the cavernous sinus, with drainage via the inferior petrosal sinus, across the midline to the contralateral cavernous sinus, and into the superior and inferior ophthalmic veins.

Courtesy of Professor Peter Mitchell

Case Discussion

Caroticocavernous fistulas are abnormal communications between the internal carotid artery and the cavernous sinus. These are rare, and occur in a variety of settings include after of base of skull fractures. The key to making the diagnosis on CTA is early filling of the superior ophthalmic vein, which is easily seen in this case on both the CTA and DSA. 

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