Direct carotid-cavernous fistula: A complication of, and treatment with, flow diversion

Direct carotid-cavernous fistulas (CCFs) are rare complications of flow diversion and have typically been documented in a subacute time frame after treatment. We present the first reported case of an intraprocedural direct CCF that developed immediately after flow diversion for treatment of a symptomatic paraclinoid right internal carotid artery aneurysm with a neck involving the cavernous segment. Endovascular treatment of such direct fistulas typically involves either transarterial obliteration of the fistulous site or transvenous embolization of the cavernous sinus. Our case was successfully treated with further immediate flow diversion without additional transvenous intervention. There are few reports on the use of flow diversion for treatment of such direct CCFs, and in all but one of these cases, flow diversion was combined with concomitant transvenous embolization. Thus, the presented case is not only the first reported case of an immediate CCF after flow diversion, but it is also only the second reported case of a direct fistula to be successfully treated using solely flow diversion, without additional transvenous intervention. We review the literature of direct CCFs after flow diversion, the pathophysiology of development of CCFs after flow diversion, the literature on treatment of CCFs with flow diversion as well as all other current treatment options.