A case of cavernous sinus dural arteriovenous fistula successfully treated using a chronic total occlusion wire

Background: In cavernous sinus dural arteriovenous fistulas (CS-dAVFs), posterior venous drainage may become occluded first, followed by anterior drainage, occasionally leading to spontaneous resolution. Immediately before this stage, however, a phenomenon known as paradoxical worsening may occur, in which symptoms rapidly deteriorate despite apparent angiographic improvement because of progressive venous outflow obstruction. In such cases, the shunt pouch (SP) becomes nearly isolated, and the lesion must be reached by penetrating the occluded cavernous sinus (CS) along a conventional access route, which is not always technically straightforward. We report a case in which a chronic total occlusion (CTO) wire enabled access to the lesion and definitive cure. Case Description: An 83-year-old woman presented to a local ophthalmologist with left conjunctival injection. Ophthalmological examination revealed full and smooth ocular movements without any obvious abnormality. Intraocular pressure was within the normal range, and no abnormal findings were noted in the visual fields or visual acuity. Brain magnetic resonance imaging demonstrated a left CS-dAVF. The lesion was fed by the middle meningeal artery and the meningohypophyseal trunk of the internal carotid artery and drained from the left CS into the left superior ophthalmic vein. Transvenous embolization (TVE) was selected, and access was obtained through the right internal jugular vein. We entered the normal right CS via the right inferior petrosal sinus and then attempted to advance into the contralateral isolated sinus; however, passage was difficult with a conventional wire. By using a CTO wire (Vassallo 40), we were able to reach the isolated SP, and the microcatheter was subsequently advanced to the shunt point, allowing curative TVE. Conclusion: We experienced a favorable case of an isolated CS shunt in which access from the normal CS was difficult, but the lesion was reached with a CTO wire and successfully treated by TVE. In cases with difficult venous access, a CTO wire may represent a useful adjunct.