Turn-Back Embolization Technique for Effective Transvenous Embolization of Dural Arteriovenous Fistulas

Schematic drawings of the risk of increasing and/or residual cortical reflux while placing coils from the distal-to-proximal segment and the turn-back embolization technique for DAVFs. A, In a TSS-DAVF with sinus occlusion like the Cognard type IIa+b or III, shunt surgery points and dangerous cortical reflux, such as the vein of Labbe and temporal veins, tend to be located at the proximal part of the transverse sinus, which is close to the occluded sinus. B and C, For such cases, standard transvenous embolization through the thrombosed sinus from the distal normal segment to the proximal abnormal segment has a risk of increased cortical venous reflux while packing from the distal to proximal part (B) or a risk of residual reflux due to insufficient packing of the shunt surgery point (C). D, In such cases, a transfemoral transvenous approach through the occluded ipsilateral sigmoid sinus can be performed. After antegrade navigation of a microcatheter into the sinus, a microguidewire is deflected at the distal end of the occluded sinus. E, Then the microcatheter is advanced to the shunt surgery point over the microguidewire. F, Microcoils can be placed into the shunt surgery point at the initial stage of sinus packing. This technique can minimize the risk of insufficient occlusion of the shunt flow when placing coils from an abnormal-to-normal segment rather than from a normal-to-abnormal segment.