APPLICATION OF ARTIFICIAL PERISTALTIC ACTUATOR FOR ESOPHAGEAL STENT

Background: The most popular and reliable surgery for patients with esophageal cancer is resection of the affected parts of the esophagus. However, such treatment reduces the quality of life of patients. To solve this problem, we have studied an artificial peristaltic actuator using a helicoid memory alloy (SMA). We have developed a moving esophageal stent which can provide peristaltic motion. Materials and Methods: An SMA was used to reproduce the peristaltic contraction. We used a specially made helicoid SMA. The SMA is endowed with high potential characteristics that can make it work as an artificial muscle. One half of a silicone pipe was covered and fixed with polyethylene terephthalate (PET). The SMA was streched on the surface of the silicone pipe, and both ends of the SMA were fixed and glued on the PET. Three segments of the SMA were sequentially set in the axial direction of the silicone pipe. The SMA segments were heated electrically to imitate peristaltic motion, and the three segments of the SMA were sequentially contracted. The peristaltic actuator was monitored by x-ray observation of contraction, and inner pressure measurement was performed to evaluate the characteristics of the artificial peristalsis. Resuts: The maximum contraction ratio of the silicone pipe was around 75% and the maximum inner pressure was 46 mmHg. Conclusion: The SMA-based peristaltic actuator showed good performance as a peristalsis device in experimental conditions. Further investigation is needed for the development of the esophageal stent, e.g., biocompatibility of materials, elasticity of esophageal tube, lubrification of inner surface, etc.