EFFICACY OF TOTAL COLONOSCOPY WITH A TRANSPARENT CAP IN COMPARISON WITH COLONOSCOPY WITHOUT THE CAP

Background and Study Aims: In spite of scrupulous inspection during ro utine colonoscopy, small lesions behind the semilunar folds can be sit uated in blind spots, where they are easily overlooked. The aim of thi s study was to evaluate the efficacy of total colonoscopy with a trans parent cap in identifying such lesions, in comparison with colonoscopy without the cap. Patients and Methods: In 24 patients with colorectal polyps, tandem colonoscopic procedures were carried out on the same d ay in random order, first without a transparent cap and then with the cap (without-to-with), or first with the cap and then without the cap (with-to-without). The time required for intubation as far as the cecu m, the number of polyps detected, and procedure-related complications were recorded. The frequencies of terminal ileal intubation and retrof lexion within the rectum were also recorded. Results: Total colonoscop y was carried out in all of the patients without any complications. Co lonoscopy with a transparent cap ensured good visual fields during ins ertion and withdrawal of the colonoscope, There were no significant di fferences in the intubation time to the cecum or in the frequency of t erminal ileal intubation between the two procedures. The miss rate for polyps was 15% in without-to-with tandem colonoscopies, and zero in w ith-to-without procedures (P=0.0125). The diameter of all the missed p olyps except for one lesion (8 mm) was less than 5 mm, Retroflexion wi thin the rectum was more difficult using the colonoscope with the cap (P<0.0001), and was successful in only one case using the cap, Conclus ions: Total colonoscopy with a transparent cap allows inspection of th e blind area of the colonic mucosa behind the semilunar folds, with go od visual fields. This method is potentially useful for both screening and diagnostic purposes.