Ruptured vertebral artery dissecting aneurysm followed by spontaneous acute occlusion and early recanalization: case report.

A 47-year-old man presented with a ruptured vertebral artery dissecting aneurysm manifesting as subarachnoid hemorrhage followed by acute occlusion and early recanalization of the affected artery. Cerebral angiography 2 hours after the onset of the symptom showed pearl-and-string sign in the right vertebral artery. Serial angiography showed that the affected artery was occluded at 12 hours but was recanalized on the 4th day. The dissecting aneurysm was resected with side-to-side anastomosis between the bilateral posterior inferior cerebellar arteries. Postoperative cerebral angiography demonstrated disappearance of the lesion and patency of the right posterior inferior cerebellar artery via the anastomosis. Histological examination of the lesion showed hematoma between the media and adventitia, disrupting the internal elastica and intima. Acute occlusion and early recanalization of the affected artery may occur in ruptured vertebral artery dissecting aneurysms. Serial neurological and neuroradiological examinations are essential to decide the timing and method of treatment.