Evaluation of hernia surgical meshes sterilised with ethylene oxide for adoption under UK regulations

Background Low- cost meshes (LCM) have been successfully used in low-income countries (LIC) over the past decades, demonstrating comparable surgical outcomes to commercial meshes at a fraction of the cost. However, LIC sterilisation standards (autoclave sterilisation at 121 degrees C) do not meet UK regulations for medical devices, which require either ethylene oxide (EO) sterilisation or steam sterilisation at 134 degrees C. Therefore, the aim of this study was to sterilise UK LCM and characterise their mechanical properties and in vitro biocompatibility to verify whether EO sterilisation causes changes in the mechanical properties and biocompatibility of LCM. Methods EO sterilised LCM were used. Uniaxial tensile tests were performed to measure mechanical properties. Biocompatibility was measured through viability and morphology of Human Dermal Fibroblasts (HDFs) cultured in mesh-conditioned media, and by calculating the metabolic activity and proliferation of HDFs attached on the meshes, with alamarBlue assay. Results Break stress of LCM1 was significantly higher than LCM2 (p < 0.0001), while Young's modulus of LCM1 was significantly lower than LCM2 (p < 0.05) and there was no significant difference in break strain. Viability and morphology showed no significant difference between LCM and control. Attachment and proliferation of HDFs on LCM showed a better proliferation on LCM2 than LCM1, with values similar to the control at the final time point. Conclusions We demonstrated that EO sterilisation affects LCM mechanical properties, but they still have values closer to the native tissues than the commercially available ones. We also showed that in vitro biocompatibility of LCM2 is not affected by EO sterilisation, as HDFs attached and proliferated on the mesh, while EO affected attachment on LCM1. A more detailed cost analysis of the potential savings for healthcare systems around the world needs to be performed to strengthen the cost- effectiveness of this frugal innovation.

Automated summary

This study investigated the effects of ethylene oxide (EO) sterilization on the mechanical properties and biocompatibility of low-cost meshes (LCM). The results showed that EO sterilization affects the mechanical properties of LCM, but they still have values close to native tissues. The biocompatibility of LCM2 was not affected by EO sterilization, as human dermal fibroblasts (HDFs) attached and proliferated on the mesh.