Summary

Endovascular treatment of carotid cavernous fistulas (CCFs) via a transvenous approach is standard, but in rare cases this approach is challenging due to absence or thrombosis of the commonly used venous routes. A 61-year-old woman presented with a symptomatic CCF with all but one of the venous access routes to the CCF thrombosed, leaving an engorged superficial middle cerebral vein (SMCV) as the only venous outflow from the cavernous sinus. Access to the CCF was made possible after careful navigation of the sigmoid sinus, the vein of Labbé and the SMCV, bypassing the need for surgical access to the SMCV or for a direct transorbital puncture. The CCF was completely occluded by coiling and Onyx embolization. The patient made an uneventful recovery, with resolution of her symptoms. To the best of our knowledge, this access route has not been previously reported in the treatment of CCFs.