Cranial dural arteriovenous shunts. Part 2. The shunts of the bridging veins and leptomeningeal venous drainage

Abstract

Leptomeningeal venous drainage of cranial dural arteriovenous fistulae is the most important determinant of adverse clinical course. Factors that predispose to its occurrence have not been adequately addressed in the literature. In the present study, we investigated the relation of shunt location to the development of leptomeningeal venous drainage, with regard to the bridging veins. Angiographic data of 211 consecutive patients with cranial dural arteriovenous fistulae treated over 19 years were analyzed. Dural shunts with leptomeningeal venous drainage were found in 107 patients; of these, 71 patients had pure leptomeningeal venous drainage (Borden type 3). The angioarchitecture of the shunt, including pattern of arterial feeders, relation with the bridging veins, primary venous drainage, and venous outflow restrictions were recorded. After analysis of the 71 Borden type 3 shunts with exclusive leptomeningeal venous drainage, three patterns emerged. The commonest was the fistula engaging a bridging vein that had lost its connection to the parent sinus into which it previously drained; it was characterized by an arterial network of feeders converging onto the wall of a bridging vein, with leptomeningeal venous reflux. The other patterns were those of "isolated" sinus segment characterized by arterial feeders converging on to the wall of the dural sinus with leptomeningeal venous reflux following the opacification of the sinus and fistulae in the vicinity of the cribriform plate with two subtypes. The main angioarchitectural features of the 36 Borden type 2 shunts with mixed sinusal-cortical venous drainage were the presence of a diffuse arterial network of vessels converging onto a site in the wall of the dural sinus, with leptomeningeal venous reflux following the opacification of the sinus. In this group, four exceptions were noticed with arterial feeders converging onto a bridging vein and having a mixed venous drainage to the cortical venous system and the sinuses. We concluded that the exact location of the shunt with regard to the bridging veins is a key factor in the development of leptomeningeal venous drainage. Cranial dural arteriovenous fistulae (CDAVFs) of either Borden type 2 or 3 do not constitute a homogeneous group. The great majority of these shunts present thrombotic phenomena.

Complex Non-sinus-associated Pachymeningeal Lymphatic Structures: Interrelationship With Blood Microvasculature

“…Positioned inside the intracranial cavity, an indistensible closed space, the dura mater not only protects intracranial structures, but also represents the critical site for CSF turnover (Dandy, 1929; Papaiconomou et al, 2004; Mack et al, 2009) and the main route for the brain venous/CSF outflow. Further, given these anatomical traits and location, there is a reason to believe that alterations within vascular networks into, and particularly out of the CNS within the cranial dura mater are significant, yet unappreciated initiators and/or contributors to a myriad neurological disorders including migraine (Glinskii et al, 2017), dural aneurysms (Baltsavias et al, 2015a, b) leading to a higher risk of intracranial hemorrhage, dural sinus/cerebral vein thrombosis (Baltsavias et al, 2015a, c), multiple sclerosis (Louveau et al, 2016), and Alzheimer’s disease (Louveau et al, 2016).…”

The Challenging Clinical Management of Patients with Cranial Dural Arteriovenous Fistula and Secondary Parkinson’s Syndrome: Pathophysiology and Treatment Options

“…It is based on the precise identification of the AV shunt localization (BVS, DSS, or EVS) as well as on the understanding of the LVD. A detailed review of the angioarchitecture of cDAVF is beyond the scope of this report and we refer the interested reader to the description by Baltsavias and Valavanis [1][2][3]6]. To achieve complete cDAVF occlusion, a multidisciplinary discussion of the endovascular and microsurgical options is recom-…”

“…A cranial dural arteriovenous fistula (cDAVF) is an acquired vascular malformation characterized by arteriovenous (AV) shunting within one of the following venous structures: the dural sinus (dural sinus shunt [DSS]), the transdural segment of the bridging veins (bridging vein shunt [BVS]), or the emissary and epidural veins (emissary vein shunt [EVS]) [1][2][3]. cDAVF represents approximately 10-15% of all intracranial AV malformations and has been described as being caused by traumatic injuries, venous sinus inflammation, brain surgery, and a hypercoagulable state [4], but the most plausible explanation of its development is sinus thrombosis, mostly as consequence of the previously listed conditions [2,5].…”

Three‐Dimensional Angles of Confluence of Cortical Bridging Veins and the Superior Sagittal Sinus on MR Venography

“…They drain blood into the dural sinuses and, subsequently, the internal jugular veins, for return to the central circulation (Mortazavi et al, ). Even within normal subjects, superficial cerebral veins can exhibit considerable variations in anatomy and configuration (Brockmann et al, ; Baltsavias et al, ; Baltsavias et al, ). Most have reciprocal relationships with the extent of brain that they drain, where a vein draining a comparatively larger area will be larger in diameter (Miller and Nader, ).…”