Surgery for a Progressive Torcular Dural Arteriovenous Fistula After Endovascular Treatment: Operative Video

A 64-year-old patient presented with signs and symptoms of intracranial hypertension. Imaging studies revealed superior sagittal sinus thrombosis, chronic left transverse sinus (TS) thrombosis and a Cognard type IIA + B dural arteriovenous fistula (dAVF) of the left TS.^1-5 Endovascular treatment was performed through arterial (ascending pharyngeal artery) and venous injection (left TS catheterization via right jugular puncture), enabling selective transvenous closure of the fistulous point with coils and Squid liquid embolic agent. At 6-month follow-up, angiography demonstrated the development of a new Cognard type I dAVF with fistulous points at the torcular Herophili, likely due to angiogenic remodeling induced by the persistence of the TS stenosis. Given the absence of cortical venous reflux and the patient's asymptomatic status, conservative management was chosen. Subsequent angiography 6 months later showed disease progression to a Cognard type IIB, along with complete occlusion of the right TS. The torcula was still opacified by the fistula, but no longer contributed to cerebral venous drainage, which had predominantly shifted anteriorly via the lateral mesencephalic vein toward the cavernous sinus and pterygoid plexuses, and through emissary and diploic veins. Endovascular treatment via the right transjugular vein was unsuccessful due to occlusive stenosis of the distal right TS. The patient underwent microsurgical exclusion of the dAVF. The torcular was disconnected from the straight sinus using a titanium clip, and a deep arterial feeder was coagulated (Video 1). Postoperatively, the patient developed a cerebrospinal fluid leak, which resolved after ventriculoperitoneal shunt placement. This case underscores the importance of multimodal treatment options in managing complex dAVFs.