170 degrees wide-angle colonoscope: effect on efficiency and miss rates.

Background: Small polyps are routinely missed during colonoscopy even with careful examination.

Aim: To determine and compare endoscopic efficiency and polyp miss rate between a prototype 170 degrees wide-angle (WA) colonoscope and a standard (S) colonoscope.

Methods: Two consecutive same-day colonoscopies were performed in 50 patients with intact colons. The patients were randomized to undergo the first colonoscopy with either the prototype WA 170 degrees angle of view colonoscope or an S adult 140 degrees angle of view colonoscope.

Results: The mean time for insertion was 2.09 (1.09) min versus 2.53 (1.47) min (p= 0.002) for the WA colonoscope and the S colonoscope, respectively. Similarly, the mean time for examination during withdrawal was shorter with the WA colonoscope (4.98 (0.94) vs 5.74 (1.12) min; p < 0.0001). The mean insertion time for the second examination was shorter than the insertion time for the first examination, irrespective of the colonoscope (p= 0.006). However, the withdrawal times were not significantly different between the first and second examinations (p= 0.11). The miss rate for all polyps with the WA colonoscope (19%) was similar to the miss rate with the S colonoscope (27%; p= 0.19). The miss rates for adenomas with the WA (10/33; 30.3%) and the S scope (15/50; 30%) were similar (p= 0.98).

Conclusions: The use of the WA colonoscope was associated with a reduction in insertion time to the cecum, as well as examination time during withdrawal. No evidence was found that the accuracy of the two colonoscopes differs.