Temporary sphincter-preserving covered biliary stent: a novel adjunctive device for cholangioscopy-guided calculi clearance

To date, cholangioscopy-guided calculi clearance has become a well-established treatment method for common bile duct (CBD) calculi [1] [2]. However, these procedures typically require endoscopic sphincterotomy (EST), which might lead to the loss of sphincter of Oddi (SO) function and some adverse events, including bleeding, perforation, cholangitis, and calculi recurrence [3]. Importantly, EST was not appropriate for those patients who could not stop taking anticoagulation/antiplatelet agents. Therefore, multiple investigators – including our team – have pioneered the deployment of a self-expandable metal stent (SEMS) prior to calculi clearance as an alternative sphincter-preserving strategy [4] [5]. However, clinical experience reveals that calculi frequently become lodged between the SEMS and biliary wall ([Fig. 1]), presenting a critical limitation to the widespread adoption of this strategy.

Fig. 1 Calculi entrapment between the self-expandable metal stent (SEMS) and the biliary wall.

In this study, we introduce an innovative temporary sphincter-preserving covered biliary stent (TSP-CBS) ([Fig. 2]) in a porcine model, engineered to prevent calculi entrapment between the SEMS and biliary wall, enabling EST-free cholangioscopy-guided calculi clearance. First, biliary intubation was conducted in a porcine model. Second, the TSP-CBS was advanced over the guidewire to the distal CBD, followed by deployment of its distal umbrella-shaped occlusive device at a predetermined position distal to the target calculi ([Fig. 3]). Third, the TSP-CBS was advanced to its predetermined deployment site, during which the target calculi was proximally displaced into upstream CBD by the expanded umbrella-shaped occlusive device ([Fig. 4]). Fourth, the TSP-CBS was deployed while eliminating calculi entrapment risk between the stent and biliary wall. Fifth, the umbrella-shaped occlusive device was collapsed and retrieved. Sixth, cholangioscope cannulation was performed through the TSP-CBS ([Fig. 5]), revealing intact biliary mucosa without iatrogenic trauma. Finally, the deployed TSP-CBS was extracted using a snare ([Video 1]).

Fig. 2 The innovative temporary sphincter-preserving covered biliary stent (TSP-CBS).

Fig. 3 The temporary sphincter-preserving covered biliary stent (TSP-CBS) was advanced over the guidewire to the distal common bile duct (CBD), followed by deployment of its distal umbrella-shaped occlusive device at a predetermined position distal to the target calculi.

Fig. 4 The temporary sphincter-preserving covered biliary stent (TSP-CBS) was advanced to its predetermined deployment site, during which the target calculi were proximally displaced into the upstream common bile duct (CBD) by the expanded umbrella-shaped occlusive device.

Fig. 5 Cholangioscope cannulation was performed through the temporary sphincter-preserving covered biliary stent (TSP-CBS).

The procedure of endoscopic sphincterotomy (EST)-free cholangioscopy-guided calculi clearance using the temporary sphincter-preserving covered biliary stent (TSP-CBS) in a porcine model.Video 1

This preclinical study validated the feasibility of EST-free cholangioscopy-guided calculi clearance using the TSP-CBS. Subsequent clinical validation will be pursued to translate this sphincter-preserving strategy.

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Publication History

Article published online:
04 September 2025

• References

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