Physicochemical, Mechanical, and Histological Assessment of Explanted Polypropylene Meshes from Recurrent Abdominal Wall Hernia Repairs.

The purpose of this study is to investigate the physical, chemical, and structural characteristics of 13 polypropylene mesh endoprostheses explanted due to hernia recurrences across an in vivo timeline ranging from 1 to 14 years, as well as the morphology of the surrounding tissues, to assess the possible influence of polymer degradation on explantation timing. Physical and mechanical testing, gas chromatography-mass spectrometry, differential scanning calorimetry, infrared spectroscopy, and histological assessment of tissue response to the implanted endoprostheses were employed. The tensile strength and elongation measurements of the explanted meshes remained within functionally acceptable clinical ranges, showing no statistically significant decline compared to baseline parameters. Polypropylene monofilaments of mesh endoprostheses were subjected to surface changes in the form of transverse cracks during exposure to patient tissues; however, the depth of these cracks was self-limiting (confined to 3-7% of the filament diameter) and did not affect the bulk strength properties of the endoprostheses. Histological examination demonstrated a chronic foreign body response that transitioned from early focal necrosis to a stable tissue capsule. While these data suggest that superficial micro-cracking did not markedly compromise bulk mechanical performance over the 14-year span, localized physical or biological tissue-implant interactions could still contribute to structural instability, meaning polymer degradation cannot be definitively ruled out as a contributing factor to recurrence in all clinical cases.