Functional and morphological evaluation of different polypropylene-mesh modifications for abdominal wall repair

Modern surgical hernia repair depends increasingly on synthetic meshes for the reconstruction of the abdominal wall. Despite the undisputed advantages of the polypropylene (PP) meshes currently available (Marlex, Prolene), reports of complications after implantation are increasing. Although, serious complications such as perforation and fistula formation are rare, minor and local complaints such as seromas, misfeelings and a decreased abdominal wall mobility are observed in about one-half of the patients. In regard to the exaggerated strength of the currently available mesh modifications a reduction of the material should improve the integration of the meshes into the artificial abdominal wall. In the present study, the commercially available basic mesh Prolene has been compared to two newly constructed PP-mesh modifications with reduced amounts of PP. The modifications have gradually been adopted to the physiological requirements of abdominal wall stability and mobility by reducing the amount of PP to 64% (E-BLUE) and 24% (variant A) of the Prolene mesh (developed by ETHICON, Norderstedt, Germany). All PP-mesh variants have been implanted in a rat model and studied by 3D-photogrammetry, tensiometry, light- and electron microscopy, as well as morphometry over implantation intervals of 3, 7, 14, 21 and 90 days. The data show that current constructions of PP-meshes are oversized and definitely restrict abdominal wall mobility in the present model. Sufficient stability of the artificial abdominal wall is even guaranteed by PP-mesh modifications with a reduction of PP-quantity to about 25% of the Prolene mesh. The degree of fibrosis directly correlated with abdominal wall restriction, whereas the formation of connective tissue in the interface PP-fibre/host-issue depends on the amount and activity of the inflammatory reaction. The quantity and quality of inflammation, again, directly relies to the amount of PP and to the surface area in contact with the recipient tissues. Altogether, the present study suggests that a modification of the PP-meshes could be helpful to prevent major and minor complications of surgical PP-meshes.