Introduction Dural type fistulas of the cavernous sinus are complex lesions; transvenous embolization is often favored but may be difficult to accomplish if there is thrombosis, stenosis or occlusion of the drainage pathways. Surgical access to the superior ophthalmic vein (SOV) is very helpful in case of difficult endovascular access to the cavernous sinus. However, it is associated with a small but additional risk. This includes inability to cannulate the SOV or treat the fistula and less commonly intraorbital hemorrhage. With the availability of newer, flexible, distal access guide catheters, these difficult to treat cases could possibly be treated using exclusively endovascular approach.

Materials and methods During the past 2 years, eight patients with symptomatic cavernous sinus fistulae were endovascularly treated by one of the authors (DG). Three of the seven lesions were considered difficult to treat using transvenous access on account of thrombosis/occlusion of the inferior petrosal sinus and presence of unfavorable angle and/or severe stenosis at the junction of the SOV with the angular vein. One of three patients had a previous failed attempt at embolization using the angular/facial vein approach. Embolization was performed in all three patients using the middle temporal vein (2/3) or facial/angular vein (1/3), with flexible, distal access guide catheters.

Results Successful catheterization of the SOV was facilitated using a combination of flexible distal access catheter (neuron or Merci distal access catheter) and a microcatheter. The flexible, guide catheters could be advanced very distally and just short of the junction of the angular vein and SOV (1/3) and supraorbital vein and SOV (2/3). This provided a stable platform and enhanced the microcatheter navigation into otherwise difficult to access SOVs. All lesions were successfully treated with this approach.

Conclusion Distal access flexible guide catheters can be advanced across tortuous venous anatomy and can even reach just short of the SOV. This helps in providing a markedly stable platform and helps superselective microcatheterization of the SOV. With the help of these newer guide catheters, many of the difficult to treat carotid–cavernous fistulas could possibly be treated using an exclusive endovascular approach thereby avoiding the need for direct surgical exposure of the SOV.