Driving experiment of an improved prototype hydraulic-driven capsule colonoscope

Kazuhiko Shinohara, MD, PhD

Tokyo University of Technology , School of Health Sciences

Background and Objective: To minimize discomfort and injury during colonoscope insertion, we developed a prototype hydraulic-driven, capsule-shaped colonoscope and a feasibility study of the hydraulic insertion of the colonoscope was performed. Initial experiments with the first prototype revealed that a weighted capsule module weighing >7 g could not pass curved courses <8 cm in radius due to friction between kinked guidewires and the center channel of the capsule module. To augment drivability on curved courses, an improved prototype was developed and driving experiments were performed in this study.

Material and Methods: Three types of capsule module (25 mm length, 15 mm diameter) with different weights (5, 7, and 11 g.) were fabricated. The 5 g module is compatible with commercially available capsule endoscopes. Each capsule module contains a channel for the guidewire and therapeutic devices, and the module is driven by water manually injected using a 10 ml syringe. The direction of movement of the capsule is controlled by the guidewire. In the improved prototype, the shape of the guidewire channel was changed to a 7 × 3 mm oval shape, from a 3 mm circle in the previous prototype. The module and syringe are connected with a vinyl tube (3 mm diameter). We prepared 4 types of curved course with a radius of 5, 7, 15, and 30 cm for driving experiments.

Results: Each type of different weighted capsule module could be driven smoothly in all 4 curved courses by manual water injection <10 ml.

Conclusion: Friction between kinked guidewires and the center channel of the capsule module was reduced by modifying the shape of the center channel in the second prototype. Greater feasibility of hydraulic-driven capsule colonoscopes was revealed in this study. Further development is ongoing to create an advanced prototype with installation of a light guide, CMOS imaging sensor, and integrated channel for the guidewire and water intake.

Session: Poster Presentation

Program Number: P375

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