Optimal reproduction of a porcine benign biliary stricture model using endobiliary radiofrequency ablation

Abstract

The use of endobiliary radiofrequency ablation (RFA) to generate a benign biliary stricture (BBS) model has a significant reproducibility problem. The aims of this animal study were to create an optimal BBS model using endobiliary RFA and determine the best way to develop it. The first step was performed on the common bile duct (CBD) of 10 miniature pigs using endoscopic RFA with a target temperature-controlled mode (80 ℃, 7 W for 90 s). The second step was performed on the CBD of five miniature pigs to understand more about the time-dependent changes in BBS development and the causes of adverse events. Using the conditions and techniques identified in the previous steps, the third step was conducted to create an optimal BBS model in 12 miniature pigs. In the first trial, four out of 10 animals died (40%) after the procedure due to cholangitis-induced sepsis. Based on this, biliary obstruction was prevented in further steps by placing a biliary plastic stent after RFA application. Histologic examinations over time showed that a severe abscess developed at the RFA application site on the fifth day, followed by fibrosis on the tenth day, and completion on the twentieth day. In the third trial, 11 animals survived (91.7%), the average BBS fibrotic wall thickness was 1107.9 µm (763.1–1864.6 µm), and the degree of upstream biliary dilation was 14.4 mm (11.05–20.7 mm). In conclusion, endobiliary RFA combined with a biliary plastic stent resulted in a safe and reproducible BBS animal model.

Balloon‐assisted laser application for endoscopic treatment of biliary stricture

“…28,35 Hence, further in vivo studies should be pursued to identify the optimal clinical settings of the proposed treatment in in vivo models with strictures (e.g., RFA-induced stricture model) for clinical translations. 36 Furthermore, only one porcine model (N = 1) was used for the proposed laser treatment in this study with a short follow-up period (1 day). Although the current in vivo study confirmed that no acute adverse events were observed, the follow-up period (24 h) was insufficient to observe chronic responses, including complications and recurrences due to scarring or deep thermal injury.…”

“…In addition, normal biliary tissue hardly reflects the characteristics of benign and malignant biliary tissue or irregularly shaped strictures with a length of 20–25 mm and a wall thickness of >3 mm 28,35 . Hence, further in vivo studies should be pursued to identify the optimal clinical settings of the proposed treatment in in vivo models with strictures (e.g., RFA‐induced stricture model) for clinical translations 36 . Furthermore, only one porcine model ( N = 1) was used for the proposed laser treatment in this study with a short follow‐up period (1 day).…”

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

“…1 C,D). The RFA electrode (ELRA electrode, 7–10-W/33-mm type, STARmed Co. Ltd, Goyang, Gyeogi-do, Korea) mounted in the CBD was used for cauterization at 10 W and 80 °C for 90 s 19 – 21 . For maximizing the contact surface between the CBD and RFA electrode, the suction technique was used 21 .…”

Dexamethasone-eluting and self-expandable biodegradable stents suppress fibrosis in biliary stricture

“…Using an in vitro bile flow phantom model, we evaluated degradation time, radial force changes, and morphologic changes of DBBS. Using an in vivo swine bile duct stricture model, we performed a DPOC examination and histopathologic evaluation to observe the biodegradation process and therapeutic effects of DBBS at regular intervals 1 2 3 .…”