The Development of a Novel Peristaltic Test Stand “Swallow-Sim” for the Mechanical Evaluation of Esophageal Stents

Abstract

Development of medical products begins with the “in silico” phase, where the development and simulation of new stent types is carried out. This is followed by the “in vitro” phase. Here, tests are done in a test stand to obtain initial conclusions about the interaction of the environment. The approval process is completed in the “in vivo” phase, where testing in living beings happen. Here, preclinical studies are carried out in animals first, followed by clinical studies on patients. A big part of the development fails in this final phase, as this is where the interactions of all influences from the stent environment are investigated. Since this not only causes high costs for the developers, but also unnecessarily destroys living resources in animal studies, this publication describes the development of a test stand called "SwallowSim" that superimposes the mechanical influences of the esophagus, the chemical stress caused by hydrochloric acid and increased body temperature. Furthermore, tests of the acting pressures are carried out using esophageal manometry, a temperature test of the test stand and a test run of the gastric juice. At the end of this publication, the results are evaluated with a six-week test of a Nickel Titanium Naval Ordnance Laboratory stent, which loses much of its mechanical properties and is partially destroyed by the load. The results show a clear correlation with the findings from reality. The test stand should be further optimised and examined in more detail in further tests and subjected to a reality check.