Congenital vertebral duplication: a predisposing risk factor for dissection.

Spontaneous cervical-artery dissection (CAD) is a major cause of cerebral ischaemia in young adults. While their pathophysiology remains still poorly understood, CAD is considered today as a multifactorial disease determined by general and local predisposing factors; these predisposing factors being predominantly constitutional abnormalities of the arterial wall. Here, we report an MRI-confirmed dissection of a duplicated vertebral artery, in a patient with attacks of vertigo due to cerebellar infarction following a minor neck trauma. Knowing that another case of vertebrobasilar CAD on a duplicated vertebral artery has been reported, these rare anatomical variants probably predispose to vertebral CAD, via local histological defects or significant hemodynamics alterations, as reported for the classical local predisposing conditions for vertebral dissection, i.e.: fibromuscular dysplasias or carotid redundancies (including loops, kinks and coils).