Can Smart Alloy Material Improve the Biomechanical Behavior of Prostheses Used in the Human Trachea? A Fluid-Structure Interaction Approach.

Background and objective: The Shape-Memory Alloy (SMA) or smart alloy stent can be used in the upper respiratory system by reducing problems such as changing the shape according to the actual conditions of the body compared to other stents.

Methods: In this study, the behavior of 2 types of SMA stents with different metallurgical properties was studied using the Finite Element Method (FEM). Tracheal geometry was obtained from CT images of a healthy man. Then, a computational model of a real human trachea was selected to analyze the deformation of the trachea after implantation of the prosthesis. Finally, it was analyzed under the maximum average static pressure of the entrance to the trachea using the Fluid-Structure Interaction (FSI) approach. A mesh based on unstructured elements for air and structured elements for the tracheal wall was created to perform simulations using ANSYS software.

Results: The deformation of the stent was compared and analyzed with the deformation of the healthy trachea in the absence of the stent. The results presented that the most deformation in the trachea before stenting is up to 8.3 mm. The behavior of SMA2 with a deformation of 5.8 mm was more consistent with the deformation conditions of the trachea for real body conditions without the presence of a stent.

Conclusions: As much as the deformation is reduced by the degree of stress concentration at the connection point of the stent to the trachea, the risks of stent displacement and patient suffocation are avoided.