Design optimization of a self-expanding polymeric microstent for the treatment of Fallopian tube occlusions

Abstract

Involuntary childlessness represents a sensitive and emotionally moving topic. Depending on the method, reproductive treatments are associated with significant physical, psychological and financial burdens. Female sterility is caused by Fallopian tube occlusions in one of three cases. Our previously described microstent technology opens up new therapeutic possibilities to restore the lumen of the Fallopian tube without surgery. In this work, Finite Element Analysis was performed for design optimization of a polymeric selfexpanding microstent which had a limited crimping diameter by self-contact resulting in challenging loading behavior during application preparation. Three different stent designs were investigated. A bilinear constitutive material model considering isotropic hardening was used for modeling of the microstent. To evaluate the stent variations, the following criteria were defined: self-contact, maximum stresses (von Mises stress) and volume of stress above 45 MPa. All microstent designs were crimped to a diameter of 1.0 mm using Finite Element Analysis. Stent design version 1 and 2 were limited to crimping diameter considering self-contact. The wave-shaped cell design of version 3 completely prevented self-contact up to a diameter of 1.0 mm. Consequently, stent design version 3 offers the greatest potential for a self-expanding polymeric microstent for minimally invasive treatment of Fallopian tube occlusions.

Keywords

• biodegradable microstent
• fallopian tube occlusion
• enabling pregnancy
• fertility treatment
• fea