A prospective randomized study on the benefits of a new small-caliber colonoscope

Background and study aims: We compared the performance efficiency of a newly developed small-caliber colonoscope (PCF-PQ260L) with passive bending, high force transmission, and an outer diameter of 9.2mm with that of a standard colonoscope, in female and male patients, particularly with regard to passage through acute angulations or into the proximal colon. Patients and methods: A total of 330 patients were randomly allocated to undergo small-caliber (n=164) or standard (n=166) colonoscopy. The patients were assessed for pain using a visual analogue scale (0=none, 100=extremely painful), and for cecal intubation, withdrawal time, difficulty of colonoscopy, dosage and level of sedation used, and any complications. Results: Median maximum pain and overall pain during colonoscopy were significantly lower in the small-caliber group than in the standard group in women (25 vs. 45, P<0.001 and 15 vs. 26, P=0.001, respectively), whereas no significant differences were seen in men (8 vs. 10, P=0.103 and 16 vs. 20, P=0.166, respectively). Furthermore, no significant differences were seen between groups in cecal intubation rate or time to cecum in all patients or by sex. Conclusions: Use of the small-caliber colonoscope reduced pain in female patients, but offered no advantage over standard colonoscopy in male patients. The performance of the small-caliber colonoscope was equivalent to that of the standard colonoscope in terms of cecal intubation rate and time to cecum, regardless of the sex of the patient.