Carotid artery stenting in a patient with an anomalous vertebral artery origin from the external carotid artery.

The existence of carotid basilar anastomoses has been well documented embryologically, anatomically, and, in the case of the persistent trigeminal and hypoglossal arteries, angiographically. Conversely, anomalous origins of the vertebral arteries (VA) are not very common with an incidence ranging from 3% to 8%. Multiple variations of the VA origin have been reported in the literature, including arising from the aortic arch, from the common, internal, or external carotid arteries and subclavian branches.1 There are only four cases reported in the literature of VA origin from the external carotid artery.2-5 We report the fifth case in which the anomalous origin was identified during the investigation of an acute ischemic stroke. Video 1 emphasizes the importance of anatomical knowledge prior to endovascular or surgical interventions. It also highlights technical nuances of carotid artery stenting in a patient with anomalous VA origin from the external carotid artery. neurintsurg;13/10/974/V1F1V1Video 1.