Master of Science
Colonoscopy is a technically challenging procedure to learn. The colonoscope is prone to forming loops in the colon, which can lead patient discomfort and even perforation. We hypothesized that expert endoscopists use techniques to avoid loop formation, and identify and straighten loops earlier, and thus exert less force.
Using a physical colon simulator model, electromagnetic tracking markers were used to follow the motion of the colon as the scope was advanced. Attending physicians exerted significantly lower mean colonic displacement than trainees.
To allow portability to any simulator, and even the clinical setting, we designed and tested the construct validity of a force-sensing sleeve for the colonoscope. It utilizes piezoresistive sensors applied in a helical orientation along the length of the colonoscope.
Force application is a marker of endoscopic competence. Our colonoscope sleeve has potential for educational and clinical use, alerting endoscopists to dangerous force application, improving patient comfort and safety.
Summary for Lay Audience
Colonoscopy is a procedure that involves the insertion of a long flexible tube with a camera and light via the anal canal. This allows the examination of the colon for diagnosis and treatment. Not surprisingly, the procedure is prone to not only discomfort, but also potential injury to the colon wall, as the scope is negotiated through the turns. Frequently, these anatomic turns in the colon result in loops being formed by the flexible scope. Our research set out to examine the force transmitted from loops in the scope to the wall of the bowel. These loops are responsible for the majority of the discomfort during the procedure, and can increase the risk of perforation.
We hypothesized that expert endoscopists would use techniques to avoid loop formation, and identify and reduce loops earlier, and would thus exert less force.
We first explored the difference between novice and expert endoscopists. We developed a training model that was able to measure how much the colon was displaced from its resting position as the colonoscope was advanced to the end of the colon. Expert endoscopists were able to advance the scope through the colon with a reduction in colonic displacement compared to their novice counterparts. This is a potential marker of competence that could be incorporated into colonoscopy training programs.
Although our simulation model worked well for training and assessment purposes, we wanted to develop a device for clinical use. Our simulation model relied on sensors placed on our model colon. For clinical use we needed our force sensors to be applied to the scope itself. We developed a layered flexible sleeve wrapped around the outside of the scope. Compression between the layers in the sleeve can be used to measure force. The helical shape of the sleeve allows for the flexibility of the scope to be maintained.
Our work has identified force application as a marker of endoscopic competence and should be incorporated into training programs. Our novel sleeve design has the potential for both educational and clinical use, alerting endoscopists to potentially dangerous force application, improving patient comfort and safety.
Hawel, Jeffrey D., "Force Application During Colonoscopy as a Marker of Competence: Development of a Novel Training Device" (2020). Electronic Thesis and Dissertation Repository. 7236.
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