A Translational Surgical Porcine Model for Postoperative Intra-Abdominal Adhesion Formation
March 13th, 2026
This protocol describes a porcine model of postoperative intra-abdominal adhesion formation using Yucatan mini pigs undergoing open abdominal surgery with bowel resection. The approach reliably induces intra-abdominal adhesions and provides a platform for evaluating adhesion development and testing anti-adhesion strategies.
This study developed a clinically relevant porcine model of postoperative intraabdominal adhesions to study adhesion biology and test anti adhesion therapies. While rodent models provide valuable insights, this protocol more closely replicates human abdominal surgery and reliably produces clinically relevant adhesions. To begin, drape the abdomen of an anesthetized pig using sterile towels and surgical drapes to maintain sterility throughout the procedure.
Perform a midline laparotomy by making a full thickness incision through the skin subcutaneous tissue and abdominal wall musculature along the linear alba to enter the peritoneal cavity using a 10 blade scalpel and electrocautery. Then eviscerate the intestines. Identify a region of the bowel, approximately 10 to 15 centimeters proximal to the ileocecal valve, and resect a 2.5-centimeter segment of the small bowel using scissors.
Resect the associated mesentary with electrocautery for hemostasis of the mesenteric blood vessels. Perform a two-layer side to side primary anastomosis. Reconstruct the inner layer of the lumen with a synthetic 3-0 absorbable suture in a running fashion and reconstruct the outer layer with a running 3-0 non-absorbable suture.
Gently abrade a three by five centimeter section of the parietal peritoneum along the right abdominal sidewall using sterile gauze or an electrocautery scratch pad. Close the fascia with a running 2-0 absorbable suture. Close the skin with a running 2-0 or 3-0 non-absorbable baseball stitch and cover with a sterile dressing.
Euthanize the animal after four weeks and assess adhesions grossly. Immediately collect tissues and blood samples for downstream analyses. Intraabdominal adhesions formed in 100%of animals evaluated on both the abraded and non-abraded sides of the abdomen.
A braided side adhesions demonstrated significantly higher adhesion scores than the non-abraded side. In all animals, adhesions involved multiple abdominal sites, including the small intestine, colon, liver, and parietal peritoneum. Adhesion tissue was carefully dissected and harvested in isolation for downstream analyses.
Histologic evaluation at four weeks revealed adhesions consisted of extracellular matrix dominated by fibroblasts and new blood vessel formation. This protocol allows researchers to study adhesion biology, fibrosis development, and test potential therapies to prevent postoperative adhesions. The most important consideration is performing standardized peritoneal injury and bowel surgery to ensure consistent and reproducible adhesion formation.
Researchers can perform gross and histologic adhesion scoring and harvest tissues for downstream molecular, cellular, and fibrosis analyses.
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Overview
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. Adhesion formation was assessed four weeks postoperatively using established gross and histologic scoring criteria by blinded observers. Adhesions developed in all animals and were multifocal, involving bowel loops, bowel-abdominal wall interfaces, peritoneal surfaces overlying organs such as the liver, and operative sites, with variable severity. Histological analysis revealed adhesions composed predominantly of extracellular matrix, fibroblasts, and blood vessels, consistent with a remodeling-phase wound healing phenotype. This model is relevant for studying abdominal adhesion fibrosis biology and translational evaluation of anti-adhesion therapeutics.
Key Study Components
Area of Science
- Surgical adhesion formation
- Wound healing and fibrosis
- Translational preclinical modeling
Background
- Postoperative intra-abdominal adhesions are a major cause of morbidity following abdominal surgery.
- Current models often lack clinical relevance or standardized assessment.
- Large animal models better recapitulate human pathophysiology and surgical complexity.
- There is a need for reproducible models to evaluate anti-adhesion therapeutics.
Purpose of Study
- Establish a clinically relevant porcine model of postoperative intra-abdominal adhesions.
- Combine intestinal resection/anastomosis with defined peritoneal injury to mimic clinical surgery.
- Standardize adhesion induction and assessment using blinded, validated scoring.
- Characterize adhesion morphology and histology at a defined postoperative timepoint.
Methods Used
- Midline laparotomy in Yucatan mini pigs
- Small bowel resection with two-layer primary anastomosis
- Unilateral parietal peritoneal abrasion
- Four-week postoperative survival period
- Blinded gross and histologic adhesion scoring
Main Results
- Adhesions formed in all animals four weeks postoperatively
- Adhesions were multifocal, involving bowel loops, bowel-wall interfaces, peritoneal surfaces over organs (e.g., liver), and operative sites
- Adhesion severity varied across animals and locations
- Histology showed adhesions rich in extracellular matrix, fibroblasts, and blood vessels
- Adhesion tissue phenotype consistent with remodeling-phase wound healing
Conclusions
- The porcine model reliably induces multifaceted postoperative intra-abdominal adhesions
- It integrates a clinically relevant intestinal procedure with standardized peritoneal injury
- Blinded, validated assessment enables reproducible adhesion quantification
- The model reflects human-like fibrosis biology, supporting mechanistic and therapeutic studies
- It provides a translational platform for evaluating anti-adhesion therapeutics in a large animal system
