David G, Humphrey J D
Department of Biomedical Engineering, M.E. DeBakey Institute, Texas A&M University, 233 Zachry Engineering Center, College Station, TX 77843-3120, USA.
J Biomech. 2003 Aug;36(8):1143-50. doi: 10.1016/s0021-9290(03)00083-6.
It has long been thought that intracranial saccular aneurysms enlarge and rupture because of mechanical instabilities. Recent nonlinear analyses suggest, however, that at least certain sub-classes of aneurysms do not exhibit quasi-static limit point instabilities or dynamic instabilities in response to periodic loading, and consequently, that the natural history of these lesions is likely governed by growth and remodeling processes. In this paper, we present additional results that support the finding that one particular sub-class of saccular aneurysms is dynamically stable. Specifically, we extended recent results of Shah and Humphrey, which are based on the assumption that some saccular aneurysms can be modeled as spherical elastic membranes surrounded by a viscous cerebrospinal fluid, to account for a viscohyperelastic behavior of the aneurysm. It is shown that inclusion of a "short-term" viscoelastic contribution to the mechanical behavior of an aneurysm serves to increase its dynamic stability against various disturbances.
长期以来，人们一直认为颅内囊状动脉瘤会因机械不稳定而扩大和破裂。然而，最近的非线性分析表明，至少某些亚类的动脉瘤在周期性负荷作用下并不表现出准静态极限点不稳定或动态不稳定，因此，这些病变的自然病程可能受生长和重塑过程的支配。在本文中，我们给出了更多结果，支持囊状动脉瘤的一个特定亚类是动态稳定的这一发现。具体而言，我们扩展了Shah和Humphrey最近的结果，其基于某些囊状动脉瘤可被建模为被粘性脑脊液包围的球形弹性膜这一假设，以考虑动脉瘤的粘弹性行为。结果表明，对动脉瘤力学行为纳入“短期”粘弹性贡献有助于增加其对各种干扰的动态稳定性。
