Spontaneous aneurysm of the extracranial vertebral artery associated with spinal osseous anomaly

Spontaneous aneurysms of the extracranial vertebral artery are uncommon. We report the case of an aneurysm located at the second cervical vertebra, associated with a congenital spinal malformation. Computed tomographic scan and arteriography were diagnostic. After proximal ligation of the vertebral artery, the aneurysm was incised and the distal vertebral artery was revascularized by an infraoccipital carotid-to-vertebral artery vein bypass.