Lending a Hand

Improving the ergonomics of the colonoscope

Abstract

Introduction: Colonoscopy is an important tool in the detection and prevention of colorectal cancer [1]. In the largest survey-based study for endoscopic related injuries (ERI) in gastroenterologists, 71% of respondents reported an ERI. More than half of the respondents (63.3%) reported pain in thumb followed by hands/fingers (59%) [2].

The endoscopist uses the left thumb to turn angular dials to steer the endoscope’s tip during the procedure. This thumb provides all the mechanical force to turn the colonoscopes tip and repeatedly exerts this force to negotiate colonic turns. The current design has not been altered much since its development [3].

Objective: The primary objective of this research is to make a more ergonomic design for the interaction interface of the colonoscope. The study will compare the ergonomic performance of endoscopists when using a directional pad compared to angular wheels for colonoscopic control.

Methods: The first phase of this study will be the development of a directional pad (D-pad) to replace the angular wheels of the colonoscope. The D-pad will translate the up-down, left-right wheel functions directly into its counterpart buttons.

The second phase of this study is a cross-sectional paired design analysis to compare endoscopists’ performance on the two interfaces. Participants will include six expert endoscopists and six trainees who will train on the new model until they reach their best cecal intubation time. The participants will then be asked to perform eight consecutive cecal intubations on a simulator. In between each intubation, grip strength will be measured using a hand grip dynamometer. The mental workload of the endoscopist using each technique will be identified using the self-reported NASA task Load Index. Non-parametric Wilcoxon analysis will be used to analyze the difference in scores between the devices.