Polymers in hernia repair–common polyester vs. polypropylene surgical meshes

Abstract

Within the last years meshes have become essential for the repair ofabdominal wall hernias. While the type of mesh obviously influencesthe clinical result, the selection of the best suitablemesh-modification should have favourable effects onto the rate ofcomplications. Available surgical meshes mainly differ in the typeand amount of the basic polymers. The most common meshes are madeeither out of monofilament polypropylene (PP) or multifilamentpolyester (PET). In the following contribution we studied thefunctional and histological results of standard and commerciallyavailable surgical meshes: a standard heavyweight, large pore-sizedPP-mesh (Prolene®), a heavyweight, large pore-sized PET-mesh(Parietex®, coated with bovine collagen) and a low weightsmall pore-sized PET-mesh (Mersilene®) in a standardised ratmodel. The meshes are studied by three dimensional stereography,tensiometry, light-(LM) and transmission electron microscopy (TEM),as well as morphometry over implantation intervals of 3, 7, 14, 21and 90 days. The results proved marked differences between thetested meshes in regard to textile properties, the mechanicalfunction (tensile strength, abdominal wall mobility), as well as thehistologically proved tissue reaction. Both heavyweight meshes (PPand PET) revealed an enormous and most similar strength whereas thelow weight PET-mesh primarily showed a considerable increase offlexibility. Despite their different structures and their diversehistological response all tested meshes led to a similar andsignificant reduction of the abdominal wall flexibility. However, thelocal tissue response of the interface mesh/recipient tissuesrevealed a significant reduction of the acute inflammatory activity anda significant decrease of connective tissue formation in the case ofthe low weight PET-mesh Mersilene® compared to both heavyweightmesh-modifications. Mersilene® showed an excellent andrelatively inert tissue reaction of the interface compared toProlene® and Parietex®. Modifications of the mesh-structure(e.g. larger pores) should improve the functional results, inparticular, abdominal wall flexibility. However, the use of PET inhernia surgery is at least questionable in respect to the obligatelong-term degradation of this polymer.