Segmental increases in force application during colonoscope insertion: quantitative analysis using force monitoring technology.

BACKGROUND: Colonoscopy is a frequently performed procedure that requires extensive training and a high skill level. OBJECTIVE: Quantification of forces applied to the external portion of the colonoscope insertion tube during the insertion phase of colonoscopy. DESIGN: Observational cohort study of 7 expert and 9 trainee endoscopists for analysis of colonic segment force application in 49 patients. Forces were measured by using the colonoscopy force monitor, which is a wireless, handheld device that attaches to the insertion tube of the colonoscope. SETTING: Academic gastroenterology training programs. PATIENTS: Patients undergoing routine screening or diagnostic colonoscopy with complete segment force recordings. MAIN OUTCOME MEASUREMENTS: Axial and radial force and examination time. RESULTS: Both axial and radial force increased significantly as the colonoscope was advanced from the rectum to the cecum. Analysis of variance demonstrated highly significant operator-independent differences between segments of the colon (zones) in all axial and radial forces except average torque. Expert and trainee endoscopists differed only in the magnitude of counterclockwise force, average push/pull force rate used, and examination time. LIMITATIONS: Small study, observational design, effect of prototype device on insertion tube manipulation. CONCLUSION: Axial and radial forces used to advance the colonoscope increase through the segments of the colon and are operator independent.