A Translational Surgical Porcine Model for Postoperative Intra-Abdominal Adhesion Formation

A porcine model of postoperative intra-abdominal adhesion formation was established using Yucatan mini pigs. The protocol combines midline laparotomy, small bowel resection with two-layer primary anastomosis, and a unilateral, parietal peritoneal abrasion in the format of an open abdominal surgical procedure. Adhesion formation was assessed four weeks postoperatively using established gross and histologic scoring criteria, with evaluations performed by blinded observers. Adhesions developed in all animals using this model and were multifocal, involving bowel loops, between the bowel and abdominal wall, involving the peritoneum overlying other organs in the abdomen (e.g. the liver), and operative sites, with variable severity. Histological analysis at four weeks demonstrated adhesions composed predominantly of extracellular matrix, fibroblasts, and blood vessels, consistent with a remodeling-phase wound healing tissue phenotype. This model is relevant for the study of abdominal adhesion fibrosis biology and/or the translational evaluation of candidate anti-adhesion therapeutics. By integrating a clinically relevant intestinal surgical procedure with a defined peritoneal injury and a standardized assessment strategy, this protocol provides a reproducible approach for inducing and evaluating postoperative intra-abdominal adhesions in a large animal model.