Original articleExperimental endoscopyActive locomotion of a paddling-based capsule endoscope in an in vitro and in vivo experiment (with videos)

BackgroundCapsule endoscopy that could actively move and approach a specific site might be more valuable for the diagnosis or treatment of GI diseases.ObjectiveWe tested the performance of active locomotion of a novel wired capsule endoscope with a paddling-based locomotion mechanism, using 3 models: a silicone tube, an extracted porcine colon, and a living pig.DesignIn vitro, ex vivo, and in vivo experiments in a pig model.SettingStudy in an animal laboratory.InterventionsFor the in vitro test, the locomotive capsule was controlled to actively move from one side of a silicone tube to the other by a controller-operated automatic traveling program. The velocity was calculated by following a video recording. We performed ex vivo tests by using an extracted porcine colon in the same manner we performed the in vitro test. In in vivo experiments, the capsule was inserted into the rectum of a living pig under anesthesia, and was controlled to move automatically forward. After 8 consecutive trials, the velocity was calculated.Main Outcome MeasurementsElapsed time, velocity, and mucosal damage.ResultsThe locomotive capsule showed stable and active movement inside the lumen both in vitro and ex vivo. The velocity was 60 cm/min in the silicone tube, and 36.8 and 37.5 cm/min in the extracted porcine colon. In the in vivo experiments, the capsule stably moved forward inside the colon of a living pig without any serious complications. The mean velocity was 17 cm/min over 40 cm length. We noted pinpoint erythematous mucosal injuries in the colon.LimitationPorcine model experiments, wired capsule endoscope.ConclusionsThe novel paddling-based locomotive capsule endoscope performed fast and stable movement in a living pig colon with consistent velocity. Further investigation is necessary for practical use in humans.