Indications for Treatment and Classification of 132 Carotid-Cavernous Fistulas

Abstract

Classification of carotid-cavernous fistulas (CCFs) into the four types described by Barrow allows the surgeon to choose the optimal therapy for each patient. Type A patients have fast flow fistulas that are manifest by a direct connection between the internal carotid arterial siphon and the cavernous sinus through a single tear in the arterial wall. The best therapy is obliteration of the connection by a detachable balloon. Ninety-two of 95 traumatic CCFs were treated in this fashion. Direct surgical exposure of the cervical or cavernous internal carotid artery (ICA) was necessary in the remaining 3 patients, who had undergone unsuccessful surgical trapping. Three ruptured cavernous aneurysms and 2 spontaneous CCFs also had Type A connections. Other carotid-cavernous fistulas are slow flow, spontaneous dural arteriovenous malformations (AVMs) that have been classified into B, C, and D types on the basis of arterial supply. Occlusion of the ICA is not a logical choice in the treatment of dural AVMs that occur in the elderly, are relatively benign, and are often bilateral. Type B are rare and are fed by meningeal branches of the ICA only. We have not seen this type of dural fistula in our series. Type C are supplied by feeders from the external carotid only and can almost always be obliterated successfully by embolizing the external carotid artery (ECA) branches. There are 4 Type C cases in this series of 37 spontaneous CCFs. All occurred in patients less than 30 years of age and were shunts between the middle meningeal artery and the cavernous sinus. Type D possess meningeal feeders from both the ICA and the ECA, often from both sides. There are 28 cases of this type. Their treatment is a real challenge. Several embolizations of the external carotid branches were always performed, but they eradicated the fistula in only 12 of 25 cases. There were 3 spontaneous cures. If the internal carotid meningeal branch feeders persist or hypertrophy after embolization of the ECA branches, surgical obliteration by the superior ophthalmic vein or the cavernous sinus approach may be necessary. In our review of 28 Type D fistulas, we are convinced that all are acquired dural AVMs, which are always associated with partial thrombosis of one or both cavernous sinuses. (Neurosurgery 22:285-289, 1988)