Angioarchitectural Evolution of Clival Dural Arteriovenous Fistulas in Two Patients

Abstract

Dural arteriovenous fistulas (dAVFs) may present in a variety of ways, including as carotid-cavernous sinus fistulas. The ophthalmologic sequelae of carotid-cavernous sinus fistulas are known and recognizable, but less commonly seen is the rare clival fistula. Clival dAVFs may have a variety of potential anatomical configurations but are defined by the involvement of the venous plexus just overlying the bony clivus. Here we present two cases of clival dAVFs that most likely evolved from carotid-cavernous sinus fistulas.

Unilateral Direct Carotid Cavernous Fistula Causing Bilateral Ocular Manifestation

“…Diagnostic imaging of CCF include CT, MR, CTAngio and MRAngio, which can show asymmetric CS widening, orbital vein and extra-ocular muscles enlargement [ 2 ]. Whereas a completely normal exam does not exclude CCF, high clinical suspicion should follow DSA, the gold standard for the diagnosis and classification [ 2 , 8 ]. DSA besides identifies location, size of the fistula and venous reflux, likewise allowing immediate treatment [ 4 ].…”

“…Ideally, the treatment should be performed when the lesion is diagnosed, and prompt treatment of high flow fistulas is recommended [ 2 , 4 , 9 ]. Even if most of the CCF is not life threatening, venous reflux causing intracranial hemorrhage or massive epistaxis can be fatal [ 4 , 8 , 10 ]. Angiographic image of dilated CS with extension into the subarachnoid space and pseudoaneurysm was associated with fatal hemorrhage by Halbach et al [ 4 ].…”

Endovascular treatment for dural arteriovenous fistulas in the petroclival region

“…The venous drainage of the upper clival DVAF is from the clival veins to the CS and the superior ophthalmic vein 22 , 34 , 47 , 48 . It can also drain to the IPS or even the cortical vein.…”

“…Currently, EVT has become a first-line option for most intracranial DAVFs, which includes transarterial embolization (TAE) and transvenous embolization (TVE) 53 . The selection of TAE or TVE should be determined in a case by case approach, which is mainly based on the individual anatomic characteristics 48 . The goal of EVT is complete obliteration of the lesion 54 .…”

“…Occasionally, for the upper clival DAVF, the draining clival venous structures can be embolized with coils via the IPS 48 . However, when the DAVFs empty directly into the clival veins rather than into the adjacent sinuses, transvenous coiling without occlusion of the fistulous sites may be ineffective 22 , 47 .…”