Aneurysms are acquired lesions related to hemodynamic stress on the arterial walls at bifurcation points and bends. Saccular or berryaneurysms are specific to the intracranial arteries because their walls lack an external elastic lamina and contain a very thin adventitia—factors that may predispose to the formation of aneurysms.
An additional feature is that they lie unsupported in the subarachnoid space.A total of 2074 strokes were registered over the 3 years. The age-standardized rate to the European population was 100.4 (95% CI 91.7 to 109.1) per 100 000 in Dijon, 123.9 (95% CI 115.6 to 132.2) in London, and 136.4 (95% CI 124.9 to 147.9) in Erlangen.
Both crude and adjusted rates were lowest in Dijon, France. Ongoing Research is being done at Subarachnoid haemorrhage centres.