Porous media properties of reticulated shape memory polymer foams and mock embolic coils for aneurysm treatment

BioMedical Engineering OnLine

Andrea D Muschenborn²  Jason M Ortega¹  Jason M Szafron²  David J Szafron²  Duncan J Maitland² 

[1] Lawrence Livermore National Laboratory, 7000 East Ave., L-090, 94551 Livermore, CA, USA

[2] Texas A&M University, 3120 TAMU, 77843 College Station, Texas, USA

关键词: Aneurysm treatment;    FHDD, Forchheimer-Hazen-Dupuit-Darcy equation;    Embolic coils;    SMP, Shape memory polymer foams;    Form factor;    Permeability;   

Others  :  797309
DOI  :  10.1186/1475-925X-12-103

 received in 2013-05-30, accepted in 2013-10-04,  发布年份 2013

【 摘 要 】

Background

Shape memory polymer (SMP) foams are being investigated as an alternative aneurysm treatment method to embolic coils. The goal of both techniques is the reduction of blood flow into the aneurysm and the subsequent formation of a stable thrombus, which prevents future aneurysm rupture. The purpose of this study is to experimentally determine the parameters, permeability and form factor, which are related to the flow resistance imposed by both media when subjected to a pressure gradient.

Methods

The porous media properties—permeability and form factor—of SMP foams and mock embolic coils (MECs) were measured with a pressure gradient method by means of an in vitro closed flow loop. We implemented the Forchheimer-Hazen-Dupuit-Darcy equation to calculate these properties. Mechanically-reticulated SMP foams were fabricated with average cell sizes of 0.7E-3 and 1.1E-3 m, while the MECs were arranged with volumetric packing densities of 11-28%.

Results

The permeability of the SMP foams was an order of magnitude lower than that of the MECs. The form factor differed by up to two orders of magnitude and was higher for the SMP foams in all cases. The maximum flow rate of all samples tested was within the inertial laminar flow regime, with Reynolds numbers ranging between 1 and 35.

Conclusions

The SMP foams impose a greater resistance to fluid flow compared to MECs, which is a result of increased viscous and inertial losses. These results suggest that aneurysms treated with SMP foam will have flow conditions more favorable for blood stasis than those treated with embolic coils having packing densities ≤ 28%.

【 授权许可】

   
2013 Muschenborn et al.; licensee BioMed Central Ltd.

【 图 表 】

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