Mechanical design of an intracranial stent for treating cerebral aneurysms

Endovascular treatment of cerebral aneurysms using stents has advanced markedly in recent years Mechanically a cerebrovascular stent must be very flexible longitudinally and have low radial stiffness However no study has examined the stress distribution and deformation of cerebrovascular stents using the finite element method (FEM) and experiments Stents can have open- and closed-cell structures and open-cell stents are used clinically in the cerebrovasculature because of their high flexibility However the open-cell structure confers a risk of in-stent stenosis due to protrusion of stent struts into the normal parent artery Therefore a flexible stent with a closed-cell structure is required To design a clinically useful highly flexible closed-cell stent one must examine the mechanical properties of the closed-cell structure In this study we investigated the relationship between mesh patterns and the mechanical properties of closed-cell stents Several mesh patterns were designed and their characteristics were studied using numerical simulation The results showed that the bending stiffness of a closed-cell stent depends on the geometric configuration of the stent cell It decreases when the stent cell is stretched in the circumferential direction Mechanical flexibility equal to an open-cell structure was obtained in a closed-cell structure by varying the geometric configuration of the stent cell (C) 2010 IPEM Published by Elsevier Ltd All rights reserved