Influence of the aspect ratio on the endovascular treatment of intracranial aneurysms: A computational investigation

Abraham Yik-Sau Tang, Siu-Kai Lai, Kar-Ming Leung, Gilberto Ka-Kit Leung, Kwok-Wing Chow

Department of Mechanical Engineering, University of Hong Kong, Pokfulam, Hong Kong.
Department of Neurosurgery, Kwong Wah Hospital, Hong Kong.
Division of Neurosurgery, Department of Surgery, Li Ka Shing Faculty of Medicine, University of Hong Kong, Queen Mary.

DOI: 10.4236/jbise.2012.58054                

Abstract

Intracranial aneurysm, a localized dilation of arterial blood vessels in the Circle of Willis and its branches, is potentially life threatening, due to massive bleeding in the subarachnoid space upon rupture. In clinical practice, one minimally invasive surgical procedure is the implantation of a metallic stent to cover the aneurysm neck. This flow diverting device can reduce the flow into the aneurysm and enhance the prospect of thrombosis, a condition expected to reduce the risk of growth and rupture. The biomechanical and haemo-dynamic factors in stented and nonstented situations are studied by computational fluid dynamics. Unlike earlier models with straight or curved parent blood vessels, the aneurysm is now located near an arterial bifurcation. The influence of the aspect (depth to neck) ratio of the aneurysm on the flow dynamics will be emphasized, especially in the post-operation stages. More precisely, the maximum flow velocity, the variations of wall shear stress, the risk of stent migration and volumetric flow rate after endovascular treatment will be studied. Aneurysms with larger aspect ratios (i.e. smaller neck sizes for constant depth) generally pose a greater risk in terms of these flow parameters. These results will assist the applications and design of stents in future neurosurgical therapy. The approach is limited to a nonelastic model, without taking into account of questions like stent expansion and interaction with tissue.

Keywords

Intracranial Aneurysm; Endovascular Treatment; Stent; Aspect Ratio; Computational Fluid Dynamics

Conflicts of Interest

The authors declare no conflicts of interest.

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