The V3 segment traverses the transverse foramen of C2 and terminates as the artery pierces the posterior atlantooccipital membrane. The V4 segment is demarcated by the atlantooccipital membrane and where the artery finally enters the foramen magnum at the base of the skull.
Vertebro-vertebral arteriovenous fistula involving the vertebral artery segment V3 is a rare vascular pathology that is either spontaneous or traumatic in origin. Furtado et al. described a post-operative traumatic vertebro-vertebral fistula in a 47-year-old lady with NF-1. They reviewed reported cases of V3 segment vertebrovertebral fistula for their incidence, etiology, clinical presentation, treatment, and outcomes using an illustrative case. Traumatic V3 segment vertebrovertebral fistula is predominantly managed with parent vessel occlusion. Per the algorithm presented, we suggest endovascular management of non-traumatic fistula be based on the anatomical variance of the contralateral vertebral artery 1).