The advantages of the 30-cm flexible sigmoidoscope over the 60-cm flexible sigmoidoscope.

To determine the optimal length of the flexible fiberoptic sigmoidoscope we performed a randomized, blinded comparison study of the standard 60-cm instrument with a prototype 30-cm instrument with identical design features. Ninety-six male patients referred for symptom evaluation underwent examination with both instruments in random order by different examiners; positive examinations were followed by colonoscopy or surgery. Performance of the 30-cm sigmoidoscope compared with the 60-cm instrument revealed that the former was significantly more likely to yield a complete examination (74 vs. 32 examinations, p less than 0.002), took less time to perform (6.4 vs. 9.8 min, p less than 0.0001), and was more acceptable to patients and physicians. The 30-cm instrument was not significantly less effective than the 60-cm instrument in detecting polyps (21 vs. 25), adenocarcinoma (six for each), and inflammatory lesions. For these reasons, we conclude that the 30-cm flexible sigmoidoscope has a role in the evaluation of colorectal complaints.