Clinical picture of intracranial non-traumatic dissecting aneurysm.

Non-traumatic intracranial arterial dissection has been accepted as a unique entity of 'cerebral infarction in otherwise healthy young adults', and is particularly prevalent in Western countries. A recent data collection and analysis have revealed additional clinical features. The nationwide study in Japan conducted in 1996 has provided new information on the natural history and current treatment of intracranial dissecting aneurysms in Japan. The incidence of symptomatic dissection was found to be much higher in the vertebrobasilar system than in the carotid system. The mean age of the patients was 51.3 years. Patients with carotid lesions were younger (mean 43.8 years). The male/female ratio was 2: 1. Fifty-eight percent of patients presented with subarachnoid hemorrhage. Recurrence was more frequent in patients with subarachnoid hemorrhage (14%) than in patients with no hemorrhage (4.2%). Common radiological findings were dilatation, 'pearl and string' sign and narrowing of the affected artery. Surgical treatment involved a variety of procedures including proximal occlusion, entrapment, wrapping and endovascular embolization. Patients with subarachnoid hemorrhage (61%) underwent surgical treatment more frequently than patients with no hemorrhage (17%). Good recovery was achieved in 64% of all patients. Outcome was better in patients with no subarachnoid hemorrhage compared with those with hemorrhage.