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Computational Analysis of Stresses Acting on Intermodular Junctions in Thoracic Aortic Endografts
Purpose To evaluate the biomechanical and hemodynamic forces acting on the intermodular junctions of a multi-component thoracic endograft and elucidate their influence on the development of type III endoleak due to disconnection of stent-graft segments. Methods Three-dimensional computer models of t...
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Published in: | Journal of endovascular therapy 2011-08, Vol.18 (4), p.559-568 |
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Main Authors: | , , , , |
Format: | Article |
Language: | English |
Subjects: | |
Citations: | Items that this one cites Items that cite this one |
Online Access: | Get full text |
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Summary: | Purpose
To evaluate the biomechanical and hemodynamic forces acting on the
intermodular junctions of a multi-component thoracic endograft and elucidate
their influence on the development of type III endoleak due to disconnection
of stent-graft segments.
Methods
Three-dimensional computer models of the thoracic aorta and a 4-component
thoracic endograft were constructed using postoperative (baseline) and
follow-up computed tomography (CT) data from a 69-year-old patient who
developed type III endoleak 4 years after stent-graft placement.
Computational fluid dynamics (CFD) techniques were used to quantitate the
displacement forces acting on the device. The contact stresses between the
different modules of the graft were then quantified using computational
solid mechanics (CSM) techniques. Lastly, the intermodular junction
frictional stability was evaluated using a Coulomb model.
Results
The CFD analysis revealed that curvature and length are key determinants of
the displacement forces experienced by each endograft and that the first 2
modules were exposed to displacement forces acting in opposite directions in
both the lateral and longitudinal axes. The CSM analysis revealed that the
highest concentration of stresses occurred at the junction between the first
and second modules of the device. Furthermore, the frictional analysis
demonstrated that most of the surface area (53%) of this junction had
unstable contact. The predicted critical zone of intermodular stress
concentration and frictional instability matched the location of the type
III endoleak observed in the 4-year follow-up CT image.
Conclusion
The region of larger intermodular stresses and highest frictional instability
correlated with the zone where a type III endoleak developed 4 years after
thoracic stent-graft placement. Computational techniques can be helpful in
evaluating the risk of endograft migration and potential for modular
disconnection and may be useful in improving device placement strategies and
endograft design. |
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ISSN: | 1526-6028 1545-1550 |
DOI: | 10.1583/11-3472.1 |