How much force is required to perforate a colon during colonoscopy? An experimental study

Area of Science:

• Gastroenterology
• Medical Engineering
• Biomechanical Engineering

Background:

• Colonoscopy is a vital diagnostic tool for large intestine pathology.
• Colon perforation is a rare but serious complication.
• The forces causing colon perforation and their relation to disease states are not well understood.

Purpose of the Study:

• To experimentally determine the forces required to perforate porcine colon tissue.
• To compare these forces across different colonoscope head configurations and loading conditions.
• To assess how these forces compare to those exerted by experienced colonoscopists.

Main Methods:

• 3D printing was used to create models of two commercial colonoscope heads.
• Porcine colon samples were subjected to load testing using these models in straight (I), 90° bent (L), and fully bent (U) configurations.
• Both perpendicular and angular load applications were tested, and results were compared to typical forces exerted by endoscopists.

Main Results:

• The force required for perforation was significantly lower for the straight (I) configuration compared to the bent (L) configuration under angular loading (14.1 vs. 46.5 N).
• Linear stiffness also varied significantly between configurations and loading types.
• Failure modes differed across configurations, with delamination common in the straight (I) configuration and full-layer failure in the fully bent (U) configuration.

Conclusions:

• The force needed to perforate the colon is dependent on the colonoscope's configuration and the mode of loading.
• Perforation risk may be higher than previously assumed, particularly when the scope advances directly against the colonic wall.
• This study provides a standardized experimental basis for further research into colonoscopic injury mechanisms.