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Abstract：
Several inflammatory conditions of the bile ducts cause strictures that prevent the drainage of bile into the gastrointestinal tract. Non-pharmacological treatments to re-establish bile flow include plastic or self-expanding metal stents (SEMs) that are inserted in the bile ducts during endoscopic retrograde cholangiopancreatography (ERCP) procedures. The focus of this study was to 3D print an anatomically accurate model of the extrahepatic bile ducts (EHBDs) with tissue-like mechanical properties to improve in vitro testing of stent prototypes. Following generation of an EHBD model via computer aided design (CAD), we tested the ability of Formlabs SLA 3D printers to precisely print the model with polymers selected based on the desired mechanical properties. We found the printers were reliable in printing the dimensionally accurate EHBD model with candidate polymers. Next, we evaluated the mechanical properties of Formlabs Elastic (FE), Flexible (FF), and Durable (FD) resins pre- and post-exposure to water, saline, or bile acid solution at 37 °C for up to one week. FE possessed the most bile duct-like mechanical properties based on its elastic moduli, percent elongations at break, and changes in mass under all liquid exposure conditions. EHBD models printed in FE sustained no functional damage during biliary stent deployment or when tube connectors were inserted, and provided a high level of visualization of deployed stents. These results demonstrate that our 3D printed EHBD model facilitates more realistic pre-clinical in vitro testing of biliary stent prototypes.
摘要：
胆管的几种炎症引起狭窄，阻止胆汁排入胃肠道。重建胆汁流的非药物治疗包括在内窥镜逆行胰胆管造影（ERCP）过程中插入胆管的塑料或自膨胀金属支架（SEM）。这项研究的重点是3D打印具有组织样机械性能的肝外胆管（EHBDs）的解剖学精确模型，以改善支架原型的体外测试。在通过计算机辅助设计(CAD)生成EHBD模型之后，我们测试了FormlabsSLA3D打印机使用基于所需机械性能选择的聚合物精确打印模型的能力。我们发现打印机在使用候选聚合物打印尺寸精确的EHBD模型方面是可靠的。接下来,我们评估了模板弹性(FE)的力学性能，Flexible(FF),和耐久(FD)树脂在暴露于水之前和之后，盐水,或胆汁酸溶液在37°C下长达一周。FE根据其弹性模量具有最类似胆管的机械性能，断裂伸长率百分比，以及在所有液体暴露条件下的质量变化。FE打印的EHBD模型在胆道支架展开期间或插入导管连接器时没有功能损伤。并提供了部署支架的高水平可视化。这些结果表明，我们的3D打印EHBD模型有助于胆道支架原型的临床前体外测试。
