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BACKGROUND: Colonoscopy has a miss rate for adenomas that may partly relate to poor visualization of the colonic surface. Dynamic position changes during colonoscope withdrawal can improve luminal distension. OBJECTIVE: To assess whether position changes also improve adenoma and polyp detection. DESIGN: Randomized crossover clinical trial. SETTING: Academic endoscopy unit. PATIENTS: This study involved 130 patients who presented for routine colonoscopy. INTERVENTION: Examination either entirely in the left lateral position followed by position changes (cecum to hepatic flexure, left lateral; transverse colon, supine; splenic flexure and descending colon, right lateral) or vice versa. After both examinations, polyps were removed for histopathology. MAIN OUTCOME MEASUREMENTS: Proportion of patients with ≥1 polyp or adenoma detected between the hepatic flexure and the sigmoid-descending colon junction. Luminal distension was measured on a scale of 1 to 5: 1, total collapse; 5, fully distended. RESULTS: At least 1 adenoma was detected in 34% of patients in colon areas in which the patient position differed from left lateral (transverse colon, splenic flexure, descending colon) compared with 23% examined with the patient in the left lateral position alone (P = .01). At least 1 polyp was detected in 52% of patients with position changes versus 34% of patients examined in the left lateral position alone (P < .001). Adenoma and polyp detection were positively correlated with an improved distension score (correlation coefficient, 0.12; P < .001). Adenomas were detected in 16% of colon areas with adequate distension scores (4 and 5) compared with 7% of those with borderline or nondiagnostic scores (1-3; P < .001). LIMITATIONS: Single-operator study. CONCLUSION: Dynamic position changes during colonoscope withdrawal significantly improved polyp and adenoma detection. ( CLINICAL TRIAL REGISTRATION NUMBER: NCT00234650).

Original publication




Conference paper

Publication Date





456 - 463


Adenoma, Adult, Aged, Aged, 80 and over, Cecum, Colon, Colonic Neoplasms, Colonic Polyps, Colonoscopy, Cross-Over Studies, Early Detection of Cancer, Female, Humans, Male, Middle Aged, Patient Positioning, Supine Position