Simultaneous dissection of intra- and extracranial vertebral artery. Report of two cases and review of literature.

Two patients who developed subarachnoid haemorrhage are presented. The first patient was a 41-year-old woman whose angiograms showed right extracranial vertebral artery (VA) dissection starting at the C2 level extending to the intracranial VA near the VA union. Proximal occlusion of the right VA by the endovascular approach was performed. The second patient was a 57-year-old man whose angiograms showed the left intracranial VA dissection distal to the posterior inferior cerebellar artery and an extracranial aneurysmal dilatation of the left VA at the C1 level and extracranial VA dissection in the V3 portion of the right VA. Left intracranial VA dissection was surgically trapped, and the remaining lesions were conservatively treated. Simultaneous dissection of the intracranial and extracranial portions of the VA is rare. Such lesions usually cause brain ischaemia, but may cause intracranial subarachnoid haemorrhage.