JOURNAL OF LAPAROENDOSCOPIC & ADVANCED SURGICAL TECHNIQUES Volume 19, Number 3, 2009 © Mary Ann Liebert, Inc. DOI: 10.1089/lap.2008.0366 Peritoneal Adhesions to Prosthetic Materials: An Experimental Comparative Study of Treated and Untreated Polypropylene Meshes Placed in the Abdominal Cavity Luca Ansaloni, MD, 1 Fausto Catena, MD, 1 Federico Coccolini, MD, 1 Milena Fini, MD, 2 Filippo Gazzotti, MD, 1 Roberto Giardino, MD, 2 and Antonio Daniele Pinna, MD, FACS 1 Abstract Background: Frequently, hernia repair requires polypropylene (PP) meshes, which carry a well-known adhe- siogenic risk when placed in contact to the intestine. The aim of this experimental study in a rat model was to assess the role of some materials, when combined with PP, in preventing the adhesions’ formation. Materials and Methods: Sixty male Sprague-Dawley rats were assigned to five groups for intraperitoneal mesh placement: untreated PP, PP+polyurethane (PP+PU), PP+Surgisis (PP+SIS), PP+expanded polytetrafluo- roethylene (PP+ePTFE), and a control group without mesh. Twenty-one days and 3 and 6 months after the op- eration, an assessment of adhesion formation was performed, scoring adhesions in terms of extent and type and the adhesion index (AI; product of adhesions’ extent and type). Results: No significant difference was seen between PP+SIS, PP+PU, and control groups in adhesions ex- tent/quality and in AI. The PP+SIS group had significantly lower adhesions’ quality value and AI than PP+ePTFE. PP+PU had significantly lower adhesions’ extent/quality value and AI than PP+ePTFE. The con- trol group had adhesions with significantly lower extent/quality and AI than PP+ePTFE. The PP group had significantly more and denser adhesions, compared to PP+ePTFE, as well as a significantly higher AI. Conclusions: Adhesions’ incidence is reduced by using treated PP meshes. PP+PU and PP+SIS were superior to PP+ePTFE in adhesion prevention. 369 Introduction A LTHOUGH HERNIA REPAIR frequently requires the use of nonabsorbable prosthetic materials, and polypropylene (PP) meshes are probably the most commonly employed for this purpose, some concerns are still present among surgeons about their use. 1,2 With the use of these types of prosthetic material comes the risk of infection of the mesh, the forma- tion of enterocutaneous fistulas, and mainly, the develop- ment of adhesions between the viscera and the mesh. 3,4 To prevent adhesions, it has been recommended to preserve the parietal peritoneum (or at least the greater omentum) dur- ing hernia repair, because it forms a barrier between the vis- cera and the PP mesh. However, in daily practice, it is some- times not feasible to preserve the parietal peritoneum nor to use the greater omentum in order to protect the abdominal contents from the direct contact with the PP mesh. More- over, some techniques of laparoscopic hernia repair, called “intraperitoneal onlay mesh,” require the intraperitoneal placement of meshes. For these reasons, efforts have been made to develop the “ideal” prosthetic material for abdom- inal wall repair. Many biomaterials, which supposedly in- duce fewer adhesions when placed in direct intestinal con- tact, were researched and developed in order to be combined with PP. The main aim of this study was to compare the ef- fectiveness in adhesion prevention of three types of treated PP mesh to that of an untreated mesh and a control group (with no mesh). Materials and Methods Animals The experimental protocol adhered to rules laid down by the Italian Animal Experimentation Act (DL 116/92) and was 1 Unit of General, Emergency, and Transplant Surgery, St. Orsola-Malpighi University Hospital, Bologna, Italy. 2 Experimental Surgery Laboratory, Research Institute Codivilla-Putti, Rizzoli Orthopaedic Institute, Bologna, Italy.