A Sigmoid-Colon-Straightening Soft Actuator With Peristaltic Motion for Colonoscopy Insertion Assistance: Easycolon

A colonoscopy is the most typical method to inspect for colorectal cancer; however, inserting colonoscopes in nonfixed sites, such as the sigmoid colon, requires very skilled insertion techniques. Since the sigmoid colon is one of the most difficult nonfixed sites for insertion, straightening it is a major step in colonoscopy. Previous studies have proposed various methods to assist the colonoscopy insertion process, but there are still challenges that must be addressed in clinical environments. The goal of this study was to assist colonoscopy operators to straighten the sigmoid colon using peristaltic motions generated with a soft actuator mounted on a commercial colonoscope. The peristaltic motions of the proposed system were combined with expanding and extending behaviors, and the straightening strategy was defined based on the analysis of the sigmoid colon handling process of colonoscopy. The peristaltic motions of the soft actuator were implemented using two balloons and a tendon-sheath mechanism. The colon shortening speed was measured to be about 80 mm/min, which contributed to the straightening of the sigmoid colon, thereby helping significantly with the process of colonoscopy.