Expandable metallic esophageal stent: Preliminary report of a lab-built process, in vitro expansile stiffness test, and in vivo placement in a pig

Esophageal cancer is a common disease in Taiwan. Although asymptomatic in the early stage, it is usually too late to be treated by curative operation once patients present with symptoms. There is still lack of effective treatment to relieve the symptoms in spite that multiple therapeutic modalities, such as radiotherapy, chemotherapy, and laser ablation, etc. are available. In this study, we designed a simple, flexible, and economic lab-built process for metallic esophageal Z-stent. A "V"-shaped model, the basic component of Z-stent, was used to determine the parameters for weaving. A method to measure the expansile stiffness was proposed to test on our lab-built and commercial stents. The results showed that the expansile stiffness of Z-stent was approximately in reverse relation to the square root of compression length. Our lab-built stent was compatible in expansile stiffness and homogeneity with the commercial Z-stent. The lab-built stent was inserted into the esophagus ora pig successfully with short-term applicability. Our developed Z-stent-manufacturing process with adjustable parameters has potentials to make stents economically and quickly adapting esophageal tumors with different sizes.