Technique for Safe Repositioning of Duckbill-Type Laser-Cut Anti-Reflux Metal Stents Using a Biliary Dilatation Balloon

Case Presentation

An 86-year-old woman with distal cholangiocarcinoma ([Fig. 1a]) initially underwent plastic stent placement but developed cholangitis 3 days later. To ensure prolonged patency, a duckbill-type anti-reflux metal stent (D-ARMS; 10 mm, 7 cm; Duckbill Biliary Stent; SB-Kawasumi Laboratories, Inc, Tokyo, Japan) was placed; however, the distal end was misplaced, leading to migration ([Fig. 1b, c]). Fifteen days later she was readmitted with cholangitis due to intrahepatic bile duct obstruction at the hepatic hilum caused by the migrated stent ([Fig. 2a]). The D-ARMS is a laser-cut metallic stent that adheres firmly to the bile duct due to its zigzag structure and cannot be narrowed by traction, making conventional removal with snares or forceps difficult and increasing the risk of bleeding or perforation. Therefore, stent removal was attempted using a biliary dilation balloon (CRE PRO Biliary Dilatation Balloon; Boston Scientific, Marlborough, Massachusetts, United States). The balloon was expanded to cover the narrowest part of the obstruction, ensuring proximal positioning to the distal end of D-ARMS (10.5 mm, 4 atm; [Fig. 2b]). Gentle traction successfully shifted the SEMS (self-expandable metal stent) distal end 1 cm downstream from the papilla ([Fig. 2c]). A plastic stent was placed for recurrence prevention ([Fig. 2d]), and the patient remained stable without further cholangitis ([Video 1]).

Video 1 Technique for safe repositioning of duckbill-type laser-cut anti-reflux metal stents using a biliary dilatation balloon.

Fig. 1 Misplacement and migration of a duckbill-type anti-reflux metal stent (D-ARMS). (a) Coronal contrast-enhanced CT image showing obstruction in the distal bile duct (red arrowhead), suggestive of distal cholangiocarcinoma. (b) Endoscopic image during ERCP showing the migrated D-ARMS (Duckbill Biliary Stent; SB-Kawasumi Laboratories, Inc., Tokyo, Japan), with only the tip of the anti-reflux valve visible at the papilla. (c) Fluoroscopic image after D-ARMS deployment, demonstrating proximal migration toward the hepatic hilum. CT, computed tomography.

Fig. 2 Repositioning of the migrated D-ARMS using a biliary dilation balloon. (a) Coronal CT image showing the proximal end of the migrated D-ARMS obstructing the intrahepatic bile duct at the hepatic hilum (red arrowhead). (b) Fluoroscopic image showing a biliary dilation balloon (CRE PRO Biliary Dilatation Balloon; Boston Scientific, Marlborough, Massachusetts, United States) covering the narrowest part of the obstruction. The balloon tip was positioned proximal to the distal end of the D-ARMS and inflated to 10.5 mm (4 atm) to conform tightly to the stent. Using the same technique as for stone extraction, the stent was gently pulled toward the papilla. (c) Endoscopic image confirming that the distal end of the SEMS had been successfully moved ∼1 cm downstream from the papilla. (d) Fluoroscopic image after ERCP showing the repositioned D-ARMS with a plastic stent inserted inside to prevent remigration. CT, computed tomography; D-ARMS, duckbill-type anti-reflux metal stent; SEMS, self-expandable metal stent.

 

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Practical Implications for Endoscopists

• Anti-reflux metal stents (ARMSs) have been developed to achieve longer patency in malignant biliary obstruction,[1] and the D-ARMS is widely used.[2] Its laser-cut structure adheres firmly to the bile duct, making removal with snares or forceps difficult and increasing the risk of bleeding or perforation.[3] In addition, the anti-reflux valve may obscure the distal end, raising the risk of migration.[4] Therefore, careful confirmation of the distal end marker during deployment is essential.

• Although removal of laser-cut metal stents (SEMS) is generally not recommended, this is the first report of safer stent repositioning using a dilation balloon to stabilize it over a broad surface than with conventional methods. While this approach may allow full removal, the risks of bleeding and perforation must be carefully considered.

• The use of D-ARMS is also expected to increase in interventional endoscopic ultrasound,[5] where this technique may serve as an important troubleshooting method.

 

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Conflict of Interest

None declared.

• References

• 1 Hu B, Wang T-T, Shi Z-M. et al. A novel antireflux metal stent for the palliation of biliary malignancies: a pilot feasibility study (with video). Gastrointest Endosc 2011; 73 (01) 143-148
• 2 Kin T, Ishii K, Okabe Y, Itoi T, Katanuma A. Feasibility of biliary stenting to distal malignant biliary obstruction using a novel designed metal stent with duckbill-shaped anti-reflux valve. Dig Endosc 2021; 33 (04) 648-655
• 3 Tanisaka Y, Ryozawa S, Kobayashi M. et al. Endoscopic removal of laser-cut covered self-expandable metallic biliary stents: a report of six cases. Mol Clin Oncol 2018; 8 (02) 269-273
• 4 Yamada Y, Sasaki T, Takeda T. et al. Removal of Duckbill-type laser-cut anti-reflux metal stents: clinical evaluation and in vitro study. DEN Open 2023; 3 (01) e217
• 5 Sasaki T, Takeda T, Sasahira N. Double stenting with EUS-CDS using a new anti-reflux metal stent for combined malignant biliary and duodenal obstruction. J Hepatobiliary Pancreat Sci 2020; 27 (11) e15-e16

Publication History

Article published online:
16 October 2025