Background: Cavernous sinus (CS) fistulas are classified into traumatic and spontaneous. Traumatic carotid-cavernous fistulas (CCFs) are usually direct internal carotid artery (ICA) high-flow fistulas; whereas spontaneous CCFs are usually dural, low-flow fistulas and generally possess less severe symptoms than direct carotid-cavernous fistulas. Methods: This study involved 34 patients who were classified into 2 groups: Group A included 26 patients with direct carotid-cavernous fistula; and Group B included 8 patients with indirect dural cavernous fistula. All patients had ocular manifestations. One patient had subarachnoid hemorrhage. Coils were used alone in 19 cases of direct fistula and in 1 case of dural fistulas. Coils and Onyx (Covidien, Mansfield, MA, USA) were used in 7 cases of direct fistula and in 2 cases of dural fistulas. Onyx alone was used to treat 5 cases with dural fistulas but none of the cases with direct fistulas. Covered stents and coils were used in 2 cases of direct fistulas. Results: All patients in both groups showed full recovery of their clinical signs and symptoms. Only 1 procedure-related complication was observed (3%) in which a patient had an embolic event and trigeminal dysesthesia as a result of Onyx reflux through external carotid artery-ICA anastomosis. Conclusion: Coils are superior solid embolic agents used for the treatment of direct high-flow fistulas, while Onyx is more valuable in dural low-flow CCF. Onyx shortens the procedure time and decreases procedure cost. Onyx injection inside the CS proper through the transarterial or transvenous route may be safer than Onyx injected inside dural arteries supplying the CS. However, more cases are needed to determine this. (C) 2015 National Stroke Association. Published by Elsevier Inc. All rights reserved.