Koichi Hirahata

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-PQ260 L) with passive bending, high force transmission, and an outer diameter of 9.2 mm 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.