What is a CCF?

Although there is a broad spectrum of lesions classified as carotid cavernous fistulas (CCFs), the fundamental abnormality is the formation of an abnormal connection between the carotid artery with a venous pouch known as the cavernous sinus at the base of the skull. This abnormal connection may be related to trauma in which case typically there is a relatively large, high-flow communication between these two structures. Alternatively, an abnormal connection can develop spontaneously from an aneurysm in this location rupturing, or an often more broad type of communication of numerous small vessels in a configuration defined as a dural arteriovenous fistula (please see separate article on this topic).

What are the symptoms of a CCF?

Due to the abnormally high pressure in the cavernous sinus in its communication with the carotid artery, blood flow in the veins reverses. The venous system of the eye is most classically affected with abnormal pressurization leading to vision changes and swelling around the orbit. This may cause permanent vision damage. If reversal of flow and abnormal pressurization of veins of the brain that connect to the cavernous sinus occurs, neurologic deficits related to the specific brain territory may occur and, in the worst case scenario, bleeding in the brain.

How is a CCF diagnosed?

The diagnosis of a CCF is usually a combination of classic clinical findings of the eye as described above, along with a CT or MRI scan showing abnormal blood flow in the cavernous sinus with associated dilated veins. The findings are then confirmed and characterized in more detail with a diagnostic cerebral angiogram.

How is a CCF treated?

The current gold standard for treatment of CCFs is endovascular embolization. There are a number of different endovascular devices, techniques and materials that can be applied to best treat a given lesion depending on its specific configuration. A CCF may be treated through the artery, through the vein, or even both. Rarely, these traditional access routes from the femoral vessels in the leg or radial/brachial vessels in the arm are not feasible for a variety of reasons. This may necessitate directly puncturing one of the veins of the orbit at the base of the eye or through the skull base, with a small puncture needle or via surgical access. Once access is obtained, the cavernous sinus is filled with coils and/or a glue-like substance called Onyx, eliminating the abnormal communication and relieving pressure on the eye and/or brain.