Development of a swine bile duct dilation model using endoclips or a detachable snare under cap-assisted endoscopy

Abstract

Background: A reproducible large animal model of bile duct dilation for the preclinical testing of new biliary devices and for training endoscopic biliary intervention is required. Surgical methods are mainly used to produce large animal models of biliary obstruction. Objective: To develop an animal model of bile duct dilation using endoscopic methods and to compare the merits of endoclips and detachable snares for the obstruction of major duodenal papillae. Design: Proof of concept experimental study. Settings: Animal laboratory. Interventions: Endoscopic clipping of the major duodenal papilla or closure of the major duodenal papilla with a detachable snare. Main Outcome Measurements: Feasibility, efficacy, and safety of endoscopic methods to develop swine models with bile duct dilation were estimated by degree of dilation at the common bile duct (CBD), intrahepatic duct (IHD), and gallbladder (GB). Results: All animals survived until the end of the experiment. Clipping of the major duodenal papilla and closure of the major duodenal papilla with a detachable snare were performed successfully in all swine. No technical difficulty or adverse event occurred during the procedures. Biliary dilatations in all animals were observed on cholangiograms (mean Delta% of postprocedural and preprocedural maximum diameters: CBD, 301%; IHD, 223.5%; GB, 34.8%). Degree of bile duct dilation in the snare group tended to be greater (CBD, 367.3%; IHD, 298.3%; GB, 47.8%) than in the endoclip group (CBD, 234.7%; IHD, 148.7%; GB, 21.8%), but this difference was not significant. An analysis of degrees of dilation according to location in the biliary tree showed that the GB was not dilated as well as the CBD or IHD. Limitations: Animal model. Conclusion: The 2 endoscopic procedures described are effective and safe for creating a swine model of bile duct dilation and could be helpful for training biliary intervention and for endoscopic biliary studies.