Impact of proximal colon retroflexion on adenoma miss rates

Small adenomas are commonly missed during routine colonoscopy. The aim of this study was to determine whether routine retroflexion in the proximal colon would improve adenoma detection rates.

One hundred patients underwent colonoscopy from the cecum to the splenic flexure by a gastroenterology fellow, with the removal of all visualized polyps. The cecum was then reintubated and patients were randomized to a second exam of the proximal colon by an experienced staff physician in either the forward view or a retroflexed view.

Two patients were excluded due to a difficult initial cecal intubation. Forty-eight patients were randomized to forward view and 50 patients were randomized to a retroflexed view. Retroflexion was successful in the cecum in 60%, the ascending colon 100%, and the transverse colon 98%. The success in retroflexion was determined in part by the type of colonoscope used. If any portion of the retroflexed examination could not be performed, that reexamination was performed in the forward view. The calculated miss rates for all polyps and adenomas among patients randomized to second examination in the forward view was 36.8% and 33.3%, respectively. The calculated miss rate for all polyps and for adenomas among patients randomized to a second examination in the retroflexed view was 38.1% and 23.7%, respectively. There was no difference in miss rates for all polyps or for adenomas (p= 0.31) when the second examination was performed in the forward view versus retroflexed view.

A second examination by retroflexion in the proximal colon did not increase the calculated miss rate relative to that performed by a forward view examination. These results do not support the addition of routine right colon retroflexion to colonoscopy.