Saccular cerebral aneurysms in young adults.

Background: The formation and rupture of cerebral aneurysms has been controversial. In order to clarify their nature, this study investigates the size and location of ruptured and unruptured aneurysms in young adults and the results of surgery.

Methods: The subjects of this study are 35 patients with ruptured and two with unruptured aneurysms. They range in age from 20 to 39 years. The size and location of their aneurysms were determined by angiographic measure of their maximal inner diameters. Direct surgery was performed on 34 patients with ruptured aneurysms and on one with an unruptured aneurysm.

Results: Ruptured aneurysms in young adults increase in number and size as they grow older. In young adults showing no atherosclerosis or hypertension, ruptured aneurysms occurred in locations and with a frequency found in patients with hypertension. In young adults, aneurysms in the internal carotid artery larger than 3.5 mm (Fisher's exact test; p < 0.05) and the anterior communicating artery showed a tendency to rupture. The surgery produced excellent results in young adults with grade I to III by Hunt and Kosnik classification, but extremely poor results for those with grade IV resulting from vasospasm (Fisher's exact test; p < 0.05).

Conclusion: It is possible that aneurysms found in young adults might in fact have been present from childhood and adolescence, increasing sufficiently in size to rupture in the forties and fifties. Accordingly, while aneurysm formation may be related to fragile arterial walls, aneurysm rupture may be the result of aging factors such as hypertension and atherosclerosis. Even in young adults, vasospasm had an impact on the outcome of surgery.