Technical Refinement of a Hybrid Surgical and Endovascular Approach for Cavernous Dural Arteriovenous Fistula with Leptomeningeal Venous Reflux: Direct Superficial Middle Cerebral Vein Exposure for Transvenous Embolization.

OBJECTIVE: Cavernous dural arteriovenous fistula (dAVF) is often treated by transvenous embolization through percutaneous routes. However, it is sometimes difficult when venous drainage flows only into leptomeningeal venous reflux. Here, we present a case of cavernous dAVF draining predominantly into the superficial middle cerebral vein (SMCV), through which endovascular coil embolization was successfully performed by direct surgical exposure. CASE PRESENTATION: A 62-year-old woman presented with left hemiparesis. Head CT revealed a right frontoparietal subcortical hematoma. Cerebral angiography showed retrograde leptomeningeal venous drainage (RLVD) caused by a right cavernous dAVF. Despite multiple percutaneous transvenous attempts, the cavernous sinus could not be accessed; therefore, a combined open surgical and endovascular approach was selected. After right frontotemporal craniotomy, the temporal cortical vein arising from a common trunk with the SMCV was preserved to reduce intra-sinus pressure and confirm fistula obliteration, with the puncture performed distal to this branch. The other drainage pathway, the SMCV, was cut down for sheath placement to secure stable access and minimize bleeding risk. A microcatheter was looped within the cavernous sinus for stability. Coil embolization was successfully completed under intraoperative digital subtraction angiography. After disappearance of shunt flow and RLVD, both the SMCV and the temporal cortical vein were coagulated and clipped. CONCLUSION: A hybrid surgical and endovascular approach can be an alternative method in cases when percutaneous transvenous embolization is not feasible. We review the combined surgical and endovascular approach and discuss the key technical considerations for successful implementation, including indications for the hybrid approach, operating room setup, craniotomy, sheath placement, coil embolization strategies, and closure.