Achievement of peristaltic design in the artificial esophagus based on esophageal characteristic analysis of goats’ specimen

In order to promote activity of daily life of patients with severe esophageal diseases, supporting peristalsis motion at the esophagus might be efficient. So we have been developing an artificial esophagus (AE) which has peristalsis motion function, and we have achieved the AE by using Ni-Ti shape memory alloy fibers. We extracted the esophagus from the epiglottis to the cardia potion from goats, which weighed 48.6±16.3 kg (n=4), after the animal experiment procedures. Prior to the measurement of characteristics of natural esophagus, we defined 5 segments in each extracted esophagus. Then we set the specimen in the static characteristic test apparatus in which we could measure segmental pressure-volume relations. Pressure and volume were measured simultaneously. All these measurement were performed within 3 hours from the extraction. Average length of each esophagus was 63±7cm. Because of the proximal segment of the specimen exhibited that the steeper increase of pressure than the distal portion near the cardia, we characterized that the distal esophagus is firmer than proximal. The proximal segment exhibited 55% bigger increase in pressure than the distal portion near the gastric cardiac part. Therefore it was suggested that compliance at the proximal portion could be lower at the small amount of internal volume. On the other hands, the extensibility of distal esophagus might be bigger than that at proximal segment. Consequently it was indicated that a new mechanical structure could be applied for the development of AE which could reproduce peristaltic motions.