Finite Element Analysis Of The Mechanical Behavior Of Braided Stent For The Treatment Of Intracranial Aneurysms

Brain arterial aneurysms are protuberance in the weak part of the cerebralarteries wall lesions and associated with high incidence of morbidity andmortality. Intracranial vessel reconstructive device as a new technology ofintravascular interventional treatment, has suffered the following deformationsin the process of using, in which the stent is crimped into the microcatheter, thendelivered along the bending blood vessel and released when arrived at the lesionlocation. Whether the stent design is reasonable primarily depends on the mainmechanical behavior above process involved which can offer a crucial guide forendovascular treatment.In this paper, aimed at the characteristic of aneurysm stent and based on theunderstanding of the vessel reconstructive device, the finite element model wasestablished by MATLAB software and finite element analysis softwareABAQUS. Self-expandable fabricated nitinol flow diverter stents including PED and various its alterations under changing braiding angle, wire diameter andstrand number were adopted in this paper. The finite element method was usedto study the mechanical behavior of stents, including the maximum strain, radialstiffness and longitudinal flexibility.The results show that the maximum equivalent uniaxial tensile strain withinthe scope of super-elastic deformation of the material in the process of crimping.The value increases as the braided angle decreases and is proportional to thewire diameter. When release the stent after reaching the lesion location, theconstruction pattern has negligible effect on the radial stiffness. While the largerthe wire diameter and the smaller the braiding angle, the greater radial stiffness.Moreover, the radial stiffness is proportional to the number of braided strands.Three kinds of construction pattern exhibit excellent wall apposition, whichmeet the requirements of cerebral artery stent reconstruction. During the processof the delivery and after implanting into the lesion location, the constructionpattern express a more obvious advantages of flexibility as reducing the numberof strands and increasing the braiding angle, especially the structural pattern B.As a key factor in determining the stent buckling performance, increasingbraiding angle will lead to a poor longitudinal flexibility. Meanwhile, increasingwire diameter and braiding strands number also results in a worse flexibility.The results of simulation analysis in this paper, to a certain extent, providea theoretical basis and reference data for searching the right parameter of variousbraiding pipe used in human body.