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

Abstract Background and Purpose : multiple carotid cavernous fistulas (CCFs) classifications have been proposed, but they lack of prediction for clinical presentation, natural history and hemorrhagic risk. Our aim is to externally validate a new classification based on the venous drainage, i.e. the Thomas classification (TC), in order to assess its relationship with symptomatology, endovascular treatment and outcome. Methods multicenter retrospective review of CCFs at 2 major academic institutions was performed. CCFs were classified according to the Barrow Classification (BC) and the TC systems. Results 94 patients with a diagnosis of CCF were collected in a time-frame of 23 years and 4 months; 89 underwent CCF treatment and 5 experienced spontaneous occlusion. Complete occlusion was achieved in 89.9% of treated patients. Complications occurred in 5.3% of patients (permanent deficits in 2.1%). TC type 4 were associated to cortical symptoms compared to type 2 ( p =.003) and type 3 ( p p p =.03, and p =.001, respectively). Transvenous posterior and transvenous anterior approach were significantly associated to TC type 2 and type 3 respectively. Excluding direct CCFs, BC was not related to treatment approach. No significant differences in outcome were found, however a trend towards lower occlusion rate in TC type 4 vs type 3 was observed. Conclusion TC provided useful information on fistula anatomy and venous hemodynamics, which correlate to clinical symptomatology and treatment strategy.