Computational model of coil placement in cerebral aneurysm with using realistic coil properties

This study presents a computational mechanical model of coil placement in cerebral aneurysms with using realistic coil properties. The mechanical behavior of the coil is expressed by solving a variational problem including the kinetic and elastic energies of the coil and geometric constraints due to the multiple contacts. The coil is discretized as a set of beam elements obeying Timoshenko beam theory, in which these elastic properties are determined based on the actual shape and material property of the coil. Numerical examples of the coil placement are presented for four cases with different coil properties in terms of the elastic property (hard and soft) and reference configurations (helical loop and complex loop) within the realistic range. These results exhibit the effects of the coil properties on not only the transition of the coil configuration during the placement process but also the contact force of the coil against the aneurysm wall which has a fatal risk of bleeding in the operation. The proposed computational model will assist surgeons to select the appropriate coil and coil deployment protocol to achieve the sufficient treatment effectiveness with minimizing the risk of bleeding in the view of the mechanical sense.