title: Materials characterization of explanted polypropylene, polyethylene terephthalate, and expanded polytetrafluoroethylene composites: spectral and thermal analysis.
abstract: This study utilized spectral and thermal analysis of explanted hernia mesh materials to determine material inertness and elucidate reasons for hernia mesh explantation. Composite mesh materials, comprised of polypropylene (PP) and expanded polytetrafluoroethylene (ePTFE) mesh surrounded by a polyethylene terephthalate (PET) ring, were explanted from humans. Scanning electron microscopy (SEM) was conducted to visually observe material defects while attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) was used to find chemical signs of surface degradation. Modulated differential scanning calorimetry (MDSC) and thermogravimetric analysis (TGA) gave thermal stability profiles that showed changes in heat of fusion and rate of percent weight loss, respectively. ATR-FTIR scans showed higher carbonyl peak areas as compared to pristine for 91% and 55% of ePTFE and PP explants, respectively. Ninety-one percent of ePTFE explants also exhibited higher C--H stretch peak areas. Seventy-three percent of ePTFE explants had higher heats of fusion while 64% of PP explants had lower heats of fusion with respect to their corresponding pristines. Only 9% of PET explants exhibited a lower heat of fusion than pristine. Seventy-three percent of ePTFE explants, 73% of PP explants, and only 18% of PET explants showed a decreased rate of percent weight loss as compared to pristine. The majority of the PP and ePTFE mesh explants demonstrated oxidation and crosslinking, respectively, while the PET ring exhibited breakdown at the sites of high stress. The results showed that all three materials exhibited varied degrees of chemical degradation suggesting that a lack of inertness in vivo contributes to hernia mesh failure.
authors.affiliation: Department of Biological Engineering, University of Missouri-Columbia, Columbia, Missouri.
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Cozad
authors.affiliation: Department of Biological Engineering, University of Missouri-Columbia, Columbia, Missouri.
authors.forename: David A
authors.initials: DA
authors.lastname: Grant
authors.affiliation: Department of General Surgery, University of Missouri-Columbia, Columbia, Missouri.
authors.forename: Sharon L
authors.initials: SL
authors.lastname: Bachman
authors.affiliation: Department of Biological Engineering, University of Missouri-Columbia, Columbia, Missouri.
authors.forename: Daniel N
authors.initials: DN
authors.lastname: Grant
authors.affiliation: Department of General Surgery, University of Missouri-Columbia, Columbia, Missouri.
authors.forename: Bruce J
authors.initials: BJ
authors.lastname: Ramshaw
authors.affiliation: Department of Biological Engineering, University of Missouri-Columbia, Columbia, Missouri.
authors.forename: Sheila A
authors.initials: SA
authors.lastname: Grant
mesh_terms: D001672:Biocompatible Materials; D046449:Hernia, Abdominal / Q000628:therapy*; D006801:Humans; D008422:Materials Testing / Q000379:methods*; D011093:Polyethylene Terephthalates; D011108:Polymers / Q000737:chemistry* / Q000627:therapeutic use; D011126:Polypropylenes; D011138:Polytetrafluoroethylene; D013057:Spectrum Analysis; D013526:Surgical Mesh / Q000592:standards*; D013818:Thermogravimetry
chemical_list: D001672:Biocompatible Materials; D011093:Polyethylene Terephthalates; D011108:Polymers; D011126:Polypropylenes; D011138:Polytetrafluoroethylene