Does retroflexion improve adenoma miss rates on the right side of the colon when using a pediatric variable-stiffness colonoscope during routine colonoscopy?

Optical colonoscopy is widely accepted as the gold standard for detecting colorectal pathology, especially adenomas and cancer. However, even in the most experienced hands, miss rates of adenomas and small cancers of up to 30 % have been reported in the literature [1] [2]. The visibility of the colorectal surface by colonoscopy is only 86.6 % compared with colonography simulation [3]. There are of course several reasons for this, one of which is the difficulty of locating adenomas that are hidden behind proximal sides of folds and the inner aspect of flexures [4] [5] [6], especially in the hepatic flexure, where the colonoscope can slip during removal [7]. Once the cecum is reached, retroflexion is often possible, and this is helpful in examining behind haustra as far as the hepatic flexure. However, retroflexion in the cecum of adult patients has proven to be significantly more successful when pediatric colonoscopes are used compared with when standard instruments are used [8] [9]. Furthermore, retroflexion in the colon facilitates resection of polyps during colonoscopy [10] [11]. So far, the impact of proximal colon retroflexion on adenoma miss rates has been negative when using normal endoscopes [12]. However, the prospective pilot study described below suggests significant advancement in colonoscopy when using pediatric variable-stiffness colonoscopes.

A single physician carried out 200 consecutive total colonoscopies (106 women, 94 men; mean age 58 years, range 18 – 88 years) using a pediatric colonoscope with variable stiffness (Olympus PCF-160 AI, Center Valley, Pennsylvania, USA). Retroflexion and meticulous inspection of the ascending colon up to the hepatic flexure was possible in 178 cases (89 %). Scopolamine butylbromide, 5 – 10 mg, was routinely given for adequate distension. In order to pass for ”total“ colonoscopy, the endoscope had to reach the orificium of the appendix with the tip of the scope; this was documented photographically.

In the first approach, the tip of the colonoscope was then retroflexed and, by rotating the endoscope slowly to the left and then to the right side while pulling it back cautiously, the ascending colon and the hepatic flexure were examined. All pathological findings were documented and photographed.

In the second approach, the tip of the endoscope was turned into anterograde view, the cecum re-intubated, and the colonoscopy thus performed in the usual manner. Again all pathological findings were immediately documented.

Neither additional pain, nor any further complications were observed during the retroflexion maneuver. No additional analgesia or sedation was needed. The average time used for the retroflexion was 32 seconds (measured on 10 consecutive endoscopies). During these examinations, a total of 18 polyps were found: nine in anterograde and retrograde view, four in anterograde-only view, and five in retrograde-only view ([Table 1]).

Table 1 Right-sided colon adenoma: visibility in relation to positioning of colonoscope. Anterograde view Retrograde view Anterograde and retrograde view Adenoma < 1 cm 4 4 7 Adenoma > 1 cm 0 1 1 Malignant polyp 0 0 1

All polyps were removed for pathological assessment.

Of the 18 polyps, five were impossible to detect in the subsequent anterograde examination, despite the advantage of already knowing the location of the polyps. In other words, 28 % of all polyps on the right side of the colon would have been missed by doing only the traditional anterograde inspection. To conclude, the data as presented here suggest a benefit from additional retroflexion on right-sided colonoscopy during routine examinations with variable-stiffness pediatric colonoscopes. However, this pilot study might have major limitations; for example the same colonoscopist performed all of the examinations and thus there was no independent control. Therefore, further work is needed to confirm this benefit.

Competing interests: None

References

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