Vertebral artery aneurysm at the level of the cervicomedullary junction--case report.

A 39-year-old male presented with a ruptured vertebral artery aneurysm at the level of the cervicomedullary junction. Neuroradiological imaging demonstrated the aneurysm but not the anatomical relationships. Surgery in the chronic stage revealed that the aneurysm arose from the lowest part of the intradural vertebral artery. No vertebral artery proximal to the aneurysmal neck was identified in the intradural space. Clipping was difficult through the intradural approach. Acute treatment of such aneurysms requires control of the extradural vertebral artery with temporary clipping.