Collagen/Polypropylene Composite Mesh Biocompatibility in Abdominal Wall Reconstruction

Background: Intraperitoneal placement of polypropylene mesh leads to extensive visceral adhesions and is contraindicated. Different coatings are used to improve polypropylene mesh properties. Collagen is a protein with unique biocompatibility and cell ingrowth enhancement potential. A novel acetic acid extracted collagen coating was developed to allow placement of polypropylene mesh in direct contact with viscera. The authors' aim was to evaluate the long-term influence of acetic acid extracted collagen coating on surgical aspects and biomechanical properties of polypropylene mesh implanted in direct contact with viscera, including complications, adhesions with viscera, strength of incorporation, and microscopic inflammatory reaction. Methods: Forty adult Wistar rats were divided into two groups: experimental (polypropylene mesh/acetic acid extracted collagen coating) and control (polypropylene mesh only). A standardized procedure of mesh implantation was performed. Animals were killed 3 months after surgery and analyzed for complications, mesh area covered by adhesions, type of adhesions, strength of incorporation, and intensity of inflammatory response. Results: The mean adhesion area was lower for polypropylene mesh/acetic acid extracted collagen coating (14.5 percent versus 69.9 percent, p < 0.001). Adhesion severity was decreased in the experimental group: grades 0 and 1 were more frequent (p < 0.04 and p < 0.002, respectively) and grade 3 was less frequent (p < 0.0001). An association between adhesion area and severity was found (p < 0.0001). Complications, strength of incorporation, and intensity of inflammatory response to the mesh were similar. Conclusions: Visceral adhesions to polypropylene mesh are significantly reduced because of acetic acid extracted collagen coating. The collagen coating does not increase complications or induce alterations of polypropylene mesh incorporation.