In an epidemiological study in Japan, tentorial dural arteriovenous fistulas (DAVFs) were less common than cavernous sinus and transverse-sigmoid sinus DAVFs (3.2% versus 45.5% and 28.3%, respectively); however, tentorial DAVFs have the most aggressive neurological behavior, with 97% causing hemorrhage or progressive focal neurological deficits. Tentorial DAVFs were classified into six types by Lawton et al. in 2008. In their literature, Type I Lawton classification was defined as a Galenic DAVF, all of which were Borden Type 3.
Neuroendovascular therapy has become the predominant treatment modality for intracranial DAVFs because the arterial supply from the external carotid artery (ECA) can be embolized safely, and the localization near the dural venous sinuses facilitates access and occlusion through that sinus. The combination of transarterial and transvenous embolization results in high obliteration rates for most DAVFs, but tentorial DAVFs are an exception. Their arterial supply is extensive, involving meningeal arteries from the internal carotid artery and vertebral artery, both of which are difficult to cannulate, and embolization is more risky compared to that of the ECA feeders. Transvenous navigation in deeper locations around the tentorium is difficult. More importantly, tentorial DAVFs (especially, Galenic DAVFs) often drain exclusively into the subarachnoid veins rather than into their associated sinuses (Borden Type 3), which prevents transvenous access. Therefore, the management of tentorial DAVFs may require microsurgical interruption, unlike most other DAVFs.
We report a case of an isolated Galenic DAVF associated with Marfan syndrome that could be completely cured with transvenous embolization alone.