In theory, Choledochojejunostomy can prevent duodenal biliary reflux by keeping food debris away from the bile duct ( Dutra et al., 2008). Duodenobiliary reflux is a remarkable phenomenon after stent implantation through duodenal papilla and has been considered another critical reason for stent occlusion ( Weickert et al., 2001 Misra and Dwivedi 2009).Ĭholedochojejunostomy and Choledochoduodenostomy are common surgical bypass operations for biliary diseases ( Shah et al., 2009). In previous studies, food fiber refluxed from the duodenum was found in stents, which proved the presence of duodenobiliary reflux ( van Berkel et al., 2005 Isayama et al., 2010). Biliary infection and cholangitis are common complications ( Sung et al., 1992 Okamoto et al., 2006), seriously affecting patients’ quality of life. However, stent placement through the duodenal papilla often damages the function of the Oddi sphincter ( Reddy et al., 2006 Hu et al., 2011) and causes the duodenal contents to reflux into the biliary tract ( Woods et al., 2005). In addition, the developed 2D equivalent FSI model provides tremendous significance for resolving the fluid-structure coupled problem of evolution solid with large deformation and markedly shortens the calculation time.Įndoscopic biliary stenting is a universal clinical palliative treatment for biliary obstruction ( Perri et al., 2013 Pranculis et al., 2017). Both the FSI model and experimental measurement indicated that the newly designed stent had superior anti-reflux performance, effectively preventing the duodenobiliary reflux while enabling the bile to pass smoothly. The finite element model revealed that the optimized anti-reflux stent possessed improved radial mechanical performance and nearly equal flexibility compared with the ordinary stent without a valve. The optimal structure of the valve was finally proposed with a high retrograde closing ratio of 95.89%.

The results of FSI analysis showed that the retrograde closure ratio of the retractable valve primarily depended on initial shear modulus of material ( p 0.05). Based on this model, four key parameters (initial shear modulus of material, thickness, pitch, and width) were selected to investigate the influence of design parameters on anti-reflux performance via an orthogonal design to optimize the stent.

A 2D equivalent fluid-structure interaction (FSI) model based on the axial section was established to analyze and evaluate the mechanical performances of the anti-reflux biliary stent. A novel anti-reflux biliary stent with a retractable bionic valve was proposed according to the concertina motion characteristics of annelids. Duodenal biliary reflux has been a challenging common problem which could cause dreadful complications after biliary stent implantation.

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