The PreOp flexible sigmoidoscopy trainer. Validation and early evaluation of a virtual reality based system

Surg Endosc. 2002 Oct;16(10):1459-63. doi: 10.1007/s00464-002-9014-4. Epub 2002 Jun 4.


Aim: To demonstrate face and construct validity of a computer based flexible sigmoidoscopy trainer.

Methods: The PreOp (Immersion Medical, USA) system is a virtual reality based flexible sigmoidoscopy simulator. The system records several performance parameters, such as percentage of colonic mucosa visualized, time taken, and pathlength of endoscope travel. Forty-five subjects were divided into three groups: novice (never performed a lower GI endoscopy), intermediate (5-50 examinations), and trained (greater than 200 examinations). After initial familiarization subjects were assessed three times on a case module. Results showed a nonparametric distribution.

Results: There was a significant difference between all three groups with respect to percentage of mucosa visualized (novice 71.0 +/- 3.7%, intermediate 77.3 +/- 5.6%, expert 84.8 +/- 4.6%, Kruskal-Wallis p <0.001) and efficiency ratio (%mucosa/time, novice 0.163 +/- 0.055, intermediate 0.259 +/- 0.07, expert 0.306 +/- 0.058, p <0.001). The novice group was also slower and had a lower pathlength of instrument travel compared to the others.

Conclusion: PreOp virtual reality simulator is a valid discriminator of flexible sigmoidoscopic experience. Its effect on training needs to be explored.

Publication types

  • Comparative Study
  • Validation Study

MeSH terms

  • Clinical Competence*
  • Education, Medical / methods*
  • General Surgery / education*
  • Humans
  • Physicians
  • Sigmoidoscopes*
  • Sigmoidoscopy*
  • United Kingdom
  • User-Computer Interface*