Structure, mechanical properties, and mechanics of intracranial saccular aneurysms

Intracranial saccular aneurysms remain an enigma; it is not known why they form, why they enlarge, or why only some of them rupture. Nonetheless, ther e is general agreement that mechanics plays an essential role in each aspec t of the natural history of these potentially deadly lesions. In this paper , we review recent findings that discount limit point instabilities under q uasi-static increases in pressure and resonance under dynamic loading as po ssible mechanisms of enlargement of saccular aneurysms. Indeed, recent hist opathological data suggest that aneurysms enlarge due to a stress-mediated process of growth and remodeling of collagen, the primary load-bearing cons tituent within the wall. We submit that advanced theoretical, experimental, and numerical studies of this process are essential to further progress in treating this class of pathologies. The purpose of this review is to provi de background and direction that encourages elasticians to contribute to th is important area of research.