Caroticocavernous Fistula Treatment & Management
- Author: Michael G Nosko, MD, PhD; Chief Editor: Brian H Kopell, MD more...
In the acute setting of vision loss and/or paralysis of cranial nerves, glucocorticosteroids (eg, dexamethasone) may be used while waiting for definitive diagnostic studies and treatments.
The definitive management of a caroticocavernous fistula is obliteration of the fistulous connection with restoration of normal arterial and venous flow. This is achieved most often through an endovascular approach. After complete delineation of the fistulous tract, an approach can be planned to close the fistula.
Type-A fistulas usually are approached through the internal carotid artery. A detachable balloon then can be positioned to occlude the fistula while maintaining patency of the internal carotid artery. Venous approaches through the internal jugular vein and the petrosal sinus may allow access to the fistula from the venous side. Guglielmi detachable coils also may be used and are becoming increasingly popular.
Type B, C, and D fistulas have smaller fistulous connections and usually are not amenable to the aforementioned treatment approaches. Carotid self-compression for 20-30 seconds 4 times per hour may lead to thrombosis of the fistula. Patients are instructed to compress the carotid artery on the side of the lesion using their contralateral hand. Should the patient develop cerebral ischemia during the compression, the contralateral hand likely will be affected, releasing the compression.
If compression is not effective or if a more rapid intervention is indicated, selective endovascular embolization of the fistula through the external carotid artery usually is effective. Several choices of embolic material are available, although polyvinyl alcohol usually is preferred.
Occasionally a fistula may require an endovascular approach through the superior ophthalmic vein. This requires surgical exposure of the vein to allow placement of the catheter.
Direct surgical exposure and obliteration of the fistula has been described. This rarely is indicated because endovascular approaches have been developed.
Severely refractory fistulas can be treated by surgical or endovascular sacrifice of the internal carotid artery. This too, rarely is indicated.
In a study of 38 patients with dural carotid-cavernous fistulas, medical treatment was performed in 16% of patients, external ocular compression in 8%, transarterial embolisation in 13%, transvenous embolisation in 60%, and radiosurgery in 3%. Clinical cure was achieved in 58% of patients and improvement in 24%; anatomical cure was demonstrated in 68%; and transient worsening or new onset of ocular symptoms was observed in 29%.
In a study of clinical and neuroradiologic results in 13 patients with carotid-cavernous fistulas treated by coiling of the cavernous sinus, there was complete occlusion of the fistula in 7 patients (7/13, 54%) and a resolution of symptoms in 8 patients (8/12, 67%). Coiling was performed with a semicompliant nondetachable balloon inflated in the internal carotid artery. The authors noted that balloon-assisted coiling permitted a clear visualization of the fistula, facilitated coil positioning, and protected the patency of the artery.
Patients usually require a follow-up angiogram to ensure that the fistula has not recurred or that alternate fistulous pathways have not developed.
Complications in untreated lesions usually are limited to visual loss, cranial nerves paralysis, and the cosmetic concerns of proptosis.
Complications of treatment include the standard complications of cerebral angiography. Arterial and venous compromise also may occur, yielding cerebral or retinal ischemia and resultant infarction.
Outcome and Prognosis
Patients with caroticocavernous fistulas generally have a good prognosis. These fistulas are associated with a high incidence of spontaneous resolution. Persistent lesions respond well to intervention. The risk of nonophthalmologic neurological complications is not significant; however, persistent untreated lesions may cause significant visual complications.
Future and Controversies
As techniques for endovascular stenting are developed further, internal carotid artery stenting across the fistula may have a role. This may provide a safer treatment option with respect to maintaining patency of the internal carotid artery while obliterating the fistula.
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