Effects of reactive oxygen species on the physical properties of polypropylene surgical mesh at various concentrations: a model for inflammatory reaction as a cause for mesh embrittlement and failure

Abstract

Background

Oxidative degradation by reactive oxygen species (ROS) from inflammation initiates cross-linking, depolymerization, and formation of a quasi-crystalline quality in polypropylene (PP) meshes that cause embrittlement (J Urol 188:1052, 2012). Embrittlement leads to change in tensile strength and is associated with post-operative complications that include pain, adhesion, dislodgment, and fragmentation.

Methods

A laboratory environment was constructed to study the relationship between concentration of ROS and change in tensile strength. Samples of Ethicon Ultrapro© PP mesh were exposed to 1 mM, 0.1 M, or 1 M hydrogen peroxide solutions for 6 months and were subjected to load displacement tensile testing (LDTT) and compared to unexposed (0 M) meshes of the same brand.

Results

Load at failure and elongation to failure after LDTT were determined with 95 % confidence interval. For unexposed (0 M) samples, tensile strength was 28.0 ± 2.4 lbf and elongation to failure was 2.0 ± 0.3 in. For samples exposed to 1 mM, tensile strength was 19.2 ± 1.1 lbf and the elongation to failure was 2.0 ± 0.1 in. For samples exposed to 0.1 M, tensile strength was 19.3 ± 1.6 lbf and elongation to failure was 1.9 ± 0.1 in. For samples exposed to 1 M, tensile strength was 20.7 ± 1.2 lbf and elongation to failure was 0.47 ± 0.02 in.

Conclusion

The results demonstrated that a 6-month exposure to a physiologic range of ROS (1 mM) decreased tensile strength of PP mesh by 31 %. 1 mM and 0.1 M samples behaved similarly demonstrating properties of a quasi-crystalline nature. 1 M samples displayed qualities of extreme embrittlement. Scanning electron microscopy (SEM) observed fiber changes. 1 M meshes had features of brittle materials. Knowledge of changes in physical properties of PP meshes is useful for considerations for the development of a more biocompatible surgical mesh.