Feasibility of in vivo swine models using guide wire-assisted intraductal radiofrequency ablation for benign biliary stricture.

Several in vivo swine models of benign biliary stenosis (BBS) have been recently reported for preclinical studies of novel endoscopic techniques and devices. The aim of this study was to evaluate the efficacy and feasibility of large animal models of BBS by using intraductal radiofrequency ablation (RFA) assisted by guide wire. Six in vivo swine models were made by using an intraductal RFA for cauterization at 10 W, 80 °C, 90 s in the common bile duct (CBD). Endoscopic retrograde cholangiopancreatography (ERCP) was performed with cholangiography and histologic evaluation was done for the common bile duct. Blood tests were examined before, after, and at the final follow-up. Guide wire assisted RFA electrode produced BBS in all (6/6, 100%) animal models without severe complications. Fluoroscopy findings at 2 weeks after intraductal RFA in every model revealed BBS in the common bile duct. In histologic evaluations, fibrosis and chronic inflammatory changes were noted. After the procedure, ALP, GGT, and CRP were elevated and decreased after an appropriate drain. A swine model of BBS is developed by inducing intraductal thermal injury using intraductal RFA assisted by guide wire. This novel technique for inducing BBS in swine is effective and feasible.