Histopathologic Analysis of Explanted Transvaginal Polypropylene Mesh

Abstract

Background: Transvaginal polypropylene (PP) meshes used to treat pelvic floor disorders have raised safety concerns due to adverse events. There is still considerable uncertainty about the causes of these complications. Objective: To identify the histological patterns that contribute to adverse events associated with PP meshes in the surgical treatment of pelvic organ prolapse (POP) and stress urinary incontinence (SUI). Study design: Eight explants were collected from seven patients (POP: four; SUI: two; POP and SUI: one), explantation due to mesh exposure or recurrent prolapse. Macroscopic and histological analyses were performed using scanning electron microscopy, light microscopy, and transmission electron microscopy. Results: Two distinct tissue responses were identified. Explants retrieved within 25 months showed rigid encapsulation by dense, well-organized collagen bundles with regular banding. In contrast, meshes removed after 33 months displayed disrupted or absent encapsulation, bacterial colonization, and significant surface degradation. Oxidative stress led to fiber fragmentation and cracking, releasing micro-debris that intensified local inflammation. Biofilm development further compromised the fibrous capsule, resulting in mesh exposure and infection in long-term cases. Conclusion: PP meshes show progressive degradation and inadequate long-term tissue integration. While early encapsulation by fibrotic tissue occurs, it fails to prevent chronic inflammation. Over time, bacterial colonization and oxidative degradation compromise the implant, often requiring removal. These findings highlight the need for alternative materials, such as polyvinylidene fluoride (PVDF), and strategies to prevent biofilm formation. Bacteriophage therapy may offer a new approach to manage mesh-related infections. Further studies with larger sample sizes are needed to confirm these results.