Date Published: September 12, 2019
Publisher: Sociedade Brasileira para o Desenvolvimento da Pesquisa em Cirurgia
Author(s): Rogério Aoki Fuziy, Ricardo Artigiani, Elesiario Marques Caetano, Ana Karina Soares Alves, Gaspar Jesus Lopes, Marcelo Moura Linhares.
To compare four types of mesh regarding visceral adhesions, inflammatory response and incorporation.
Sixty Wistar rats were divided into four groups, with different meshes implanted intraperitoneally: polytetrafluoroethylene (ePTFE group); polypropylene with polydioxanone and oxidized cellulose (PCD); polypropylene (PM) and polypropylene with silicone (PMS). The variables analyzed were: area covered by adhesions, incorporation of the mesh and inflammatory reaction (evaluated histologically and by COX2 immunochemistry).
The PMS group had the lowest adhesion area (63.1%) and grade 1 adhesions. The ePTFE and PM groups presented almost the total area of their surface covered by adherences (99.8% and 97.7% respectively) The group ePTFE had the highest percentage of area without incorporation (42%; p <0.001) with no difference between the other meshes. The PMS group had the best incorporation rate. And the histological analysis revealed that the inflammation scores were significantly different. The PM mesh had higher density of adherences, larger area of adherences, adherences to organs and percentage of incorporation. ePTFE had the higher area of adherences and lower incorporation. The PMS mesh performed best in the inflammation score, had a higher incorporation and lower area of adherences, and it was considered the best type of mesh.
Incisional hernias are one of the most frequent postoperative complications1 Obesity, advanced age, diabetes, pulmonary diseases, malnutrition and multiple surgeries at the same site are predisposing factors. Several hernia correction methods have been proposed; yet none is considered the gold standard in the repair of incisional hernias, and the treatment of obese patients, with multiple hernia lesions or abdominal wall loss is even more complex2.
This research protocol was approved by the institutional ethics committee (protocol CEP 1292/11), as it fully adheres to all national and institutional guidelines for the care and use of the animals used in experimental researches, and also the current national laws.
Two rats died during the experiments, one in the PMS group and the other in the PM group. Both deaths occurred in the immediate postoperative period and followed the increase of anesthetic doses for surgery. The study thus began with 14 animals in the PM and PMS groups and 15 in the PCD and ePTFE groups. However, it was not possible to perform immunohistochemistry analysis in all rats due to problems with the slides staining. COX-2 evaluation was performed in 14 animals in the PM and PCD groups, 13 animals in the PMS group and 12 animals in the ePTFE group.
Although the correction of abdominal wall hernias with the mesh is one of the most frequent interventions in the daily life of the general surgeon, there are still many doubts about the host response to various types of mesh used in this procedure. Intraperitoneal mesh, sometimes with direct contact with abdominal organs, has been increasingly used21 and there are more than 600 products available22, most still pending clinical trials before use in humans. A gap in the literature, that this study tried to fill, was the study of inflammatory reactions, scarring and postoperative complications with different types of products, as adherences, intestinal fistulae and infection are common complications23,24. The idea of coating mesh with physical or chemical barriers to adherences was promising, but these substances could potentially impair incorporation and increase the risk of infection. In this study, the polypropylene mesh coated with silicone (PMS) had the best incorporation and the lowest area of adherences.
Among all types of mesh studied, the polypropylene mesh (PM) had higher density of adherences, larger area of adherences, adherences to organs and percentage of incorporation. The polytetrafluoroethylene expanded mesh (ePTFE) had the higher area of adherences and lower incorporation. The polypropylene mesh coated with silicone (PMS) performed best in inflammation score, had a higher incorporation and lower area of adherences, and it was considered the best type of mesh regarding inflammation, adherences and incorporation. However, this is an experimental study with rats, with short follow-up, and there are no other studies that could be compared to ours in the literature yet.