Construct validation of a physical model colonoscopy simulator

Background: Previous studies have demonstrated the construct validity of virtual reality colonoscopy simulators by showing that they can distinguish between users according to their level of endoscopic experience. Although physical model simulators are known to simulate looping more realistically than these devices, they lack published validation evidence.

Objective: To assess the construct validity of a physical model simulator, the Kyoto Kagaku Colonoscope Training Model (Kyoto Kagaku Co. Ltd, Kyoto, Japan) and to determine its suitability for assessing the insertion skill of trainee colonoscopists.

Design: Validation study; 21 experienced colonoscopists and 18 novices made 2 attempts at each of 4 standard cases on the Kyoto Kagaku physical model simulator, and we compared their performance on each case.

Setting: A medical simulation center in a large tertiary hospital.

Main outcome measurements: Completion rates, times to cecum, and peak forces applied to the colon model.

Results: Compared with novices, experienced colonoscopists had significantly higher completion to cecum rates and shorter times to cecum for each of the 4 cases (all P < .005). For 2 cases, experienced colonoscopists also exerted significantly lower peak forces than did novices (both P = .01).

Limitations: Two of the model's 6 "standard cases" were not included in the study.

Conclusions: The 4 cases included in the study have construct validity in that they can distinguish between the performance of experienced colonoscopists and novices, reproducing experienced/novice differences found in real colonoscopy. These cases can be used to validly assess the insertion skill of colonoscopy trainees.