Surgical transvenous embolization of a carotid-cavernous dural fistula with cortical drainage via a petrosal vein: two technical case reports

OBJECTIVE AND IMPORTANCE: We present two interesting cases involving carotid-cavernous dural fistulae draining only or predominantly into the petrosal vein after previous incomplete, complicated, endovascular treatments. Transvenous embolization with Guglielmi detachable coils, via the petrosal vein, during surgical exposure completely obliterated the fistulae. CLINICAL PRESENTATION: A 64-year-old man manifesting left ocular symptoms after incomplete embolization of a left carotid-cavernous dural fistula and a 56-year-old woman manifesting left hemiparesis after complicated embolization of a right carotid-cavernous dural fistula were referred to our hospital. A percutaneous transvenous approach was attempted in both cases, but the catheter could not reach the fistula site. A combined open surgical and endovascular approach was then used. INTERVENTION: The hemispheric branch of the petrosal vein was exposed via a retromastoid craniectomy. The catheter was then directly introduced into the hemispheric branch, followed by navigation into the fistula site. The fistula was completely embolized with Guglielmi detachable coils. CONCLUSION: The technique of surgical transvenous embolization via a petrosal vein is a valuable alternative for the treatment of carotid-cavernous dural fistulae that drain only or predominantly into the petrosal vein, when the percutaneous transvenous route is not accessible.