Effects of Ethylene Oxide Resterilization and In-vitro Degradation on Mechanical Properties of Partially Absorbable Composite Hernia Meshes
T. Endogan, I. Ozyaylali, H. Kulacoglu, K. Serbetci, G. Kiyak, N. HasirciOriginal article, no. 6, 2013
Background and Aim: Prosthetic mesh repair for abdominal wallhernias is widely used because of its technical simplicity and lowhernia recurrence rates. The most commonly used material ispure polypropylene mesh, although newer composite materialsare recommended by some centers due to their advantages.However, these meshes are more expensive than pure polypropylenemeshes. Resterilization of a pure polypropylene mesh hasbeen shown to be quite safe, and many centers prefer slicing alarge mesh into smaller pieces, suitable for any hernia type ordefect size. Nevertheless there is no data about the safety afterresterilization of the composite meshes. The present study wascarried out to investigate the effects of resterilization and in vitrodegradation in phosphate buffered saline solution on thephysical structure and the mechanical properties of partiallyabsorbable lightweight meshes.Methods: Two composite meshes were used in the study: Onemesh consists of monofilament polypropylene and monofilamentpolyglecaprone -a copolymer of glycolide and epsilon(ε) - caprolactone - (Ultrapro®, 28 g m2, Ethicon, Hamburg,Germany), and the other one consisted of multifilamentpolypropylene and multifilament polyglactine (Vypro II®, 30g m2, Ethicon, Hamburg, Germany). Two large meshes were cutinto rectangular specimens sized 50 x 20 mm for mechanicaltesting and 20 x 20 mm for in vitro degradation experiments.Meshes were divided into control group with no resterilizationand gas resterilization. Ethylene oxide gas sterilization wasperformed at 55°C for 4.5 hours. In vitro degradation in 0.01M phosphate buffered saline (PBS, pH 7.4) solution at 37 Â+-1°C for 8 weeks was applied to one subgroup in each meshgroup. Tensiometric measurements and scanning electronmicroscopic evaluations were completed for control andresterilization specimens.Results: Regardless of resterilization, when the meshes wereexposed to in vitro degradation, all mechanical parametersdecreased significantly. Highest reduction in mechanicalproperties was observed for Ultrapro due to the degradation ofabsorbable polyglecaprone and polyglactin parts of these meshes. It was observed that resterilization by ethylene oxidedid not determine significant difference on the degradationcharacteristics and almost similar physical structures wereobserved for resterilized and non-resterilized meshes. For VyproII meshes, no significant mechanical difference was observedbetween resterilized and non-resterilized meshes afterdegradation while resterilized Ultrapro meshes exhibitedstronger characteristics than non-resterilized counterparts, afterdegradation.Conclusion: Resterilization with ethylene oxide did not affectthe mechanical properties of partially absorbable compositemeshes. No important surface changes were observed inscanning electron microscopy after resterilization.