The marginal sinus normal anatomy and involvement with arteriovenous fistulae

Rationale and Objectives: The marginal sinus is an infrequently recognized dural venous sinus at the rim of the foramen magnum. Recognition of this sinus and knowledge of its anatomy will enable the neurointerventionalist to treat dural arteriovenous fistulae (AVF) involving the marginal sinus. Methods: We present a report of the signs, symptoms, angiographic appearance, and treatment results of two patients with marginal sinus dural AVF. In addition, we review the literature concerning the marginal sinus and describe the anatomy of this region. Angiograms depicting normal variants are presented to illustrate the various patterns that may be encountered when the marginal sinus participates in the venous drainage of the cranium. Results: In two patients with dural arteriovenous fistulae (AVF) the marginal sinus was found to be the venous receptacle. The marginal sinuses are dural venous sinuses located at the lateral margins of the foramen magnum. Superiorly, the marginal sinus connects to the occipital sinus, a single or paired midline venous channel arising at the torcular Herophili or the medial transverse sinus. The marginal sinus typically drains into the sigmoid sinus, and may connect to the condylar veins, the superior aspect of the internal venous plexus, or the occipital plexus. Occasionally, the occipital-marginal sinus system represents the primary drainage pathway of the cranium, completely replacing the transverse sinus. In the two patients we treated with dural AVF in this location, simple transvenous packing of the sinus effectively cured the lesion. Conclusions: The marginal sinus is a dural venous sinus that can rarely be involved with a dural AVF. Recognition that a dural AVF involves the marginal sinus can facilitate safe, effective therapy.