A structured framework to evaluate Capsule Endoscope Locomotion Systems

Abstract Although capsule endoscopes have advanced significantly over the past two decades, their original passive design remains. Developing active locomotion systems for capsule endoscopes is a research-intensive field, and several such systems have been devised, using a variety of bioengineering solutions. While many of these systems are at various stages of testing - from theoretical to bench to in-vivo - only one has made it to pre-clinical trials. What is clear is the absence of a standardised system to evaluate and compare the different technologies. In this paper, we set out a structured framework with which to evaluate Capsule Endoscope Locomotion Systems (CELS). The criteria set upon which it is based is derived from agreed clinically optimal conditions. The existing literature on CELS is then systematically reviewed and analysed using the framework, to demonstrate its validity. The average design score for existing CELS is 59.86% (range: 44.54% - 78.74%). We found that the lowest-performing designs used inchworm and vibratory locomotion, whereas the highest-scoring designs all had magnetic actuation incorporated in some form. It is expected that the proposed new framework will enable clinicians, researchers, and manufacturers to consider global evaluative criteria when developing CELS and to apply them to existing and future system solutions.