Endoscopic ultrasound-guided biliary drainage in a novel radiofrequency ablation-based swine biliary dilatation model

Endoscopic ultrasound (EUS)-guided drainage procedures are becoming increasingly widespread in clinical practice, even though they are technically challenging and require a substantial learning curve. In vivo swine biliary dilatation models for training have been described; however, they provide erratic biliary dilatation and can also be technically cumbersome [1 – 5]. We describe EUS-guided gallbladder drainage with a lumen-apposing metal stent (LAMS) in a novel swine biliary dilatation model.

A 30-kg minipig underwent endoscopic retrograde cholangiography and temperature-controlled endobiliary radiofrequency ablation (EB-RFA) of the distal common bile duct (CBD) with a dedicated RFA system (ELRA, STARmed) ([Video 1]). The ablation consisted of 10 W of power delivered via an endobiliary catheter-electrode, with a temperature sensor at a target temperature of 80 °C, for two rounds of 90 seconds. After 11 days, the pig was re-examined with a linear EUS scope, which revealed dilatation of both the intrahepatic and extrahepatic biliary ducts, including the gallbladder. At the distal third of the CBD, an RFA-induced hyperechoic lesion was detected ([Fig. 1]).

Video 1 Video showing endoscopic ultrasound-guided biliary drainage with a lumen-apposing metal stent in a novel swine biliary dilatation model obtained with a temperature-controlled endobiliary radiofrequency ablation system.

Fig. 1 Endoscopic ultrasound images in a minipig model showing: a the normal common bile duct (CBD) and portal vein (PV) at the hepatic hilum viewed from the stomach before radiofrequency ablation (RFA) of the distal CBD; b the distal CBD viewed from the stomach following RFA with evidence of dilatation of the CBD and intrahepatic biliary ducts (*); c the RFA-induced hyperechoic lesion (arrows) in the distal CBD seen from the bulb; d the distal flange of the lumen-apposing metal stent, seen from the gastric antrum and correctly deployed in the distended gallbladder (**).

The distended gallbladder was accessed from the gastric antrum with a 19G needle (Expect, Boston Scientific). A 0.025-inch guidewire (VisiGlide 2, Olympus) was then inserted through the needle and coiled into the gallbladder. After a cholecystogastric fistula had been created using a wire-guided needle knife (MicroKnife, Boston Scientific), the tract was dilated with a 6-mm balloon (Hurricane, Boston Scientific). Finally, a 10 × 20-mm LAMS (Spaxus, Taewoong) was placed under combined EUS, fluoroscopic, and endoscopic guidance ([Fig. 2]).

Fig. 2 Endoscopic view showing the proximal flange of the lumen-apposing metal stent correctly deployed in the gastric antrum.

Temperature-controlled EB-RFA of the distal CBD proved to be a straightforward, effective, and novel technique to create a biliary stricture with subsequent massive upstream biliary dilatation. EUS-guided gallbladder drainage with a LAMS was feasible in this model, which is theoretically suitable also for other EUS-guided biliary interventions. Furthermore, the swine model provides excellent haptic feedback and suitable levels of realism in comparison to procedures undertaken in humans.

Endoscopy_UCTN_Code_TTT_1AU_2AB

Competing interests

None

• References

• 1 Lee TH, Choi JH, Lee SS. et al. A pilot proof-of-concept study of a modified device for one-step endoscopic ultrasound-guided biliary drainage in a new experimental biliary dilatation animal model. World J Gastroenterol 2014; 20: 5859-5866
• 2 Alcaide N, Lorenzo-Pelayo N, Ruiz-Zorrilla R. et al. Endoscopic porcine model of biliary obstruction using over-the-scope clips: feasibility and applicability to training in EUS-guided drainage procedures. Gastrointest Endosc 2013; 77: AB294-AB295
• 3 Minaga K, Kitano M, Itonaga M. et al. Endoscopic ultrasound‑guided biliary drainage using a newly designed metal stent with a thin delivery system: a preclinical study in phantom and porcine models. J Med Ultrason 2018; 45: 391-397
• 4 Park JS, Jeong S, Kim JM. et al. Development of a swine benign biliary stricture model using endoscopic biliary radiofrequency ablation. J Korean Med Sci 2016; 31: 1438-1444
• 5 Rumalla A, Petersen BT, Baron TH. et al. Development of a swine model for benign stenosis of the bile duct by endoscopic application of intraluminal thermal injury. Gastrointest Endosc 2003; 57: 73-77