Dissection of bilateral intracranial vertebral artery with basilar artery involvement: a case report of a patient free from neurological deficits.

We report a patient with dissection of the bilateral intracranial vertebral artery (VA) that did not present any symptoms other than occipital headache, which was probably associated with sleeping overnight in a car seat with unsteady head position. Although cerebral angiography revealed extensive dissection of the bilateral VA after branching of the posterior inferior cerebral artery, retrograde flow to the basilar artery (BA) via the right posterior communicating artery contributed to preserved posterior circulation. These findings indicate that even in patients without neurological deficits, the involvement of BA cannot be excluded and that accurate evaluation using radiological techniques should be considered.