The measurement of forces exerted during colonoscopy

Background: The widely varying forces used at colonoscopy have not been mea sured, An electronic device was designed to measure the forces exerted by t he clinician on the endoscope during colonoscopy. Methods: The device featured a handle designed in the shape of a hinged spl it cylinder that could be locked around the endoscope but readily moved up and down the insertion tube as the colonoscopy proceeded. This cylinder con tained strain-gauges arranged so that the forces transmitted could be accur ately measured. The device recorded the torque forces in addition to the pu sh and pull forces exerted during diagnostic colonoscopy. Results: In a series of 21 colonoscopies in 20 patients: peak pushing force = 4.4 kg, pulling force = -1.8 kg, anticlockwise torque = 1.0 Newton meter s, clockwise torque = 0.8 Newton meters. Percentage time force greater than 1 kg = 5%, Peak anal insertion force = 1.8 kg. Conclusions: These measurements represent the first accurate measurements o f the forces exerted during colonoscopy. Reducing the force during colonosc opy is likely to diminish pain and reduce the risk of perforation. A knowle dge of these forces may also help with the design of new instruments and mo dels for teaching or research.