Carotid Cavernous Fistulas and Dural Arteriovenous Fistulas of the Cavernous Sinus: Validation of a New Classification According to Venous Drainage.

Abstract

Multiple carotid cavernous fistula (CCF) classifications have been proposed. However, they lacked predictive factors for the clinical presentation, natural history, and hemorrhagic risk. Our aim was to externally validate a new classification according to venous drainage (i.e., the Thomas classification [TC]) to assess its relationship with symptoms, endovascular treatment, and outcomes. We performed a multicenter retrospective review of CCFs at 2 major academic institutions. The CCFs were classified using the Barrow classification (BC) and TC systems. The data from 94 patients with a diagnosis of CCF were collected during a study period 23 years, 4 months. Of these 94 patients, 89 had undergone CCF treatment and 5 had experienced spontaneous occlusion. Complete occlusion was achieved in 89.9% of the treated patients. Complications occurred in 5.3% of the patients, including permanent deficits in 2.1%. TC type 4 was associated with cortical symptoms compared with type 2 (P = 0.003) and type 3 (P < 0.001). The BC was not able to detect significant differences among the symptom types. Significant differences were found using the TC for the transarterial-only, transvenous anterior-only, and transvenous posterior-only approaches (P < 0.001, P = 0.03, and P = 0.001, respectively). The transvenous posterior and transvenous anterior approach were significantly associated with type 2 and 3 TC, respectively. Excluding direct CCFs, the BC was not related to the treatment approach. No significant differences in the outcomes were found. However, a trend toward a lower occlusion rate for TC type 4 compared with type 3 was observed. The TC provided useful information regarding the fistula anatomy and venous hemodynamics, which correlated with the clinical symptoms and treatment strategy.