Numerical Modeling of Coil Compaction in the Treatment of Cerebral Aneurysms using Porous Media Theory

Abstract

A numerical study was conducted to quantify the reduction in blood velocity and pressure resulting from the placement of endovascular coils within a cerebral aneurysm using physiological velocity waveforms. The flow characteristics within the aneurysm sac were modeled using the volume‐averaged porous media equations. We studied the effects of narrow and wide aneurismal necks on the velocity fields and pressure within its sac in the absence of the coils. Wide‐neck aneurysms experience higher velocity and pressure than narrow‐neck aneurysms within the sac at peak systole. Our study shows that velocity fields are significantly affected by the presence of endovascular coil within the aneurysm sac. Moreover, we estimated that a volume density of 20% platinum coil in the aneurysmal sac was sufficient to cause sufficient blood flow arrest in the aneurysm to allow for thrombus formation. The present model, using porous media theory, permits the study of fluid motion across small spaces of variable and complex geometry. Additional refinements will be required to describe the permeability of a coil inserted in a patient based on its porosity, geometry and shape.