Abstract
Abstract This study was aimed at evaluating the in vitro degradation, the in vivo biocompatibility and at comparing the effects of two methods of sterilization on poly( L ‐lactic acid) (PLA 94 ) resorbable mesh. The mesh was manufactured to be used as surgical soft tissue reinforcement in the vaginal area. Samples of 100 mg of PLA 94 mesh (10 × 10 mm 2 ) were immersed in isoosmolar 0.13 M , pH 7.4 phosphate buffer solution at 37°C, during 12 months. The hydrolytic degradation up to 12 months after immersion was monitored by measuring weight loss, mesh area changes, and by various analytical techniques namely Differential scanning calorimetry (DSC), capillary zone electrophoresis (CZE), size exclusion chromatography (SEC), and environmental scanning electron microscopy (ESEM). Specimens of nonsterilized, ethylene‐oxide (ETO) sterilized, and γ‐ray sterilized PLA 94 mesh were compared. Fifteen samples were implanted in an incisional hernia Wistar rat model. Histopathology was performed up to 90 days after implantation to evaluate the inflammatory response and the collagen deposition. Although the decrease of molecular weight due to polymer chain scissions started 6 weeks after in vitro immersion, water‐soluble degradation products and decrease of tensile strength appeared after 8 months only. Analyses showed also that ETO sterilization did not affect the degradation of the PLA 94 mesh. In contrast, γ‐ray sterilization increased very much the sensitivity of the mesh to the hydrolytic degradation. In vivo , the PLA 94 mesh exhibited good biocompatibility over the investigated time period. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2008