Development of an animal model for assessment of primary end-to-end biliary reconstruction
BACKGROUND: Bile duct anastomotic stricture after bile duct injury or liver transplantation remains as the most formidable clinical problem. Here, we attempt to describe the natural course of healing following experimental end-to-end anastomosis (EEA) and to evaluate the efficacy and safety of EEA in a rabbit model. METHODS: New Zealand rabbits were divided into experimental groups with complete transection of the common bile duct (CBD) and control group with CBD mobilization. Clinical, laboratory biochemical and cholangiographical manifestations were compared between the groups. At intervals postoperatively healing course of the bile duct was judged by macroscopic, microscopic and transmission electron microscope examination. The diameters of CBD were measured by sliding caliper. RESULTS: Serum concentrations of alkaline phosphatase, alanine aminotransferase and total bilirubin were significantly higher in experimental groups than those in control group (P < 0.05). The cholangiogram showed that anastomotic stricture and markedly dilated biliary tree were observed at varying time postoperatively. Inflammatory reactions, cicatricial stricture and fibrosis in the bile duct wall were observed in the experimental groups. In addition, biliary fibroblast increased and collagen deposition was observed in the anastomotic scar tissue. We observed that 3 (6%) rabbits had formed gallstones within 1–3 months after injury EEA. CONCLUSIONS: This study demonstrated that microsurgical techniques could achieve successful primary end-to-end biliary repair in the rabbit. Anastomotic tension, surgical technology and fibrotic healing may be the most important causes of stricture formation. Additionally, this model may allow for researching the pathologic changes in the healing process of the bile duct and the mechanisms of stricture formation.