Testing softer elastomeric membranes for pelvic organ prolapse repair

Abstract

<h4>Importance</h4>Pain and mesh exposure in polypropylene mesh augmented pelvic organ prolapse repairs are linked to stiffness mismatches and mesh deformations (pore collapse and wrinkling). To overcome these limitations, we are developing novel elastomeric membranes (EMs) that are macroporous and fabricated from a material that is softer than polypropylene (eg, polycarbonate urethane) and more closely matches the stiffness of the vagina.<h4>Objectives</h4>This study assessed how pore geometry (auxetic-bowtie vs nonauxetic square or diamond) and material distribution affect the elongation, wrinkling, and porosity of EMs in response to tensile loads using finite element (FE) simulations.<h4>Study design</h4>Nine models with varied strut dimensions were designed maintaining constant total volume, device length, and device width. FE analysis based on a Neo-Hookean material model was used to apply 15 N uniaxial tensile loads in flat clamped and suture-like configurations.<h4>Results</h4>For both configurations, diamond-pore membranes showed the greatest elongation and porosity loss, and square pore membranes showed the least. The suture-like configurations caused wrinkling that was most pronounced in bowtie-pore membranes, especially near attachment points, and least in square-pore membranes. The elongation of bowtie-pore membranes was most sensitive to material distribution, which also directly corresponded to the degree of wrinkling.<h4>Conclusions</h4>Square pore geometry offered superior stability in response to uniaxial tension. Auxetic bowtie models showed porosity advantages, but material distribution affected their elongation and corresponding propensity to wrinkle. These findings are critical for optimizing membrane design to minimize complications.