A prospective trial of variable stiffness pediatric vs. standard instrument colonoscopy Arthur John Kaffes, MBBS, FRACP, Animesh Mishra, MBBS, Steven Leslie Ding, MBChB, FRACP, Rick Hope, MBBS, FRACP, Stephen John Williams, MBBS, FRACP, MD, Peter Edward Gillespie, MBBS, FRACP, Michael John Bourke, MBBS, FRACP Westmead, Sydney, Australia Background: The pediatric variable stiffness colonoscope is believed to have theoretical advantages over the standard colonoscope, however a systematic evaluation of this instrument in routine clinical practice involving adult patients is lacking. Methods: Consecutive patients (blinded) undergoing colonoscopy in an outpatient endoscopy center by one of 4 experienced colonoscopists had the procedure performed with a standard colonoscope (n = 384) or pediatric variable stiffness colonoscope (n = 413). Failure to negotiate the sigmoid colon within 10 minutes was regarded as a failure and, if suitable, the patient was crossed over to colonoscopy with the alternative instrument. Results: Median (95% CI) time to the cecum was significantly faster in the pediatric variable stiffness colonoscope group (odds ratio 5.0: 95% CI[4.7,5.3] minutes) compared with the standard colonoscope group (odds ratio 5.5: 95% CI[5.2,5.8] minutes, p = 0.01). There were 22 failures overall (2.8%), 14 in the standard colonoscope group (3.6%) and 8 in the pediatric variable stiffness colonoscope group (1.9%; p = 0.1). With regard to the 14 failures in the standard colonoscope group, colonoscopy was attempted with the pediatric variable stiffness colonoscope in 13 and completed successfully in 12 (92%). The pediatric variable stiffness colonoscope was superior in cases of severe stenosing diverticular disease; two of 27 examinations with the pediatric variable stiffness colonoscope were rated as failed vs. 12 of 18 with the standard colonoscope (p < 0.001). Conclusions: Intubation time was faster with the pediatric variable stiffness colonoscope, but use of this instrument was not associated with a superior cecal intubation rate compared with the standard colonoscope. However, in patients with severe stenosing diverticular disease, the intubation rate with the pediatric variable stiffness colonoscope was superior. (Gastrointest Endosc 2003;58:685-9.) With the emergence of colorectal cancer screening programs, the demand for outpatient colonoscopy will increase. 1-3 This has implications for colonoscopy completion times, sedation requirements, and rate of cecal intubation. Despite widespread diffusion of colo- noscopic technical proficiency throughout the de- veloped world, the failure rate for cecal intubation remains significant at up to 10%. 4,5 Modifications or improvements in colonoscopes may improve out- comes. The use of standard pediatric colonoscopes in adult patients has been studied. 6-9 It is suggested that these colonoscopes have a theoretical advantage over standard colonoscopes (SC) because of their narrower diameter and greater flexibility. However, these instruments may be subject to recurrent looping, which likely lengthens procedure time and limits routine application. 6 Despite these problems, the standard pediatric colonoscope has been used suc- cessfully in ‘‘difficult colons’’ where a tight or stenosed sigmoid colon could not be negotiated with a SC. 6-8 To maximize cecal intubation rates and times, the ideal instrument would offer a broad range of both flex- ibility and stiffness, which could be varied by the endoscopist, as well as a narrow diameter insertion tube. The pediatric variable stiffness colonoscope (PVSC) offers all of these features. There are several studies of the use of variable stiffness (VS) colonoscopes in adults, and the results are either conflicting or limited by the small numbers of patients. 10-16 In a multicenter study involving over Received March 13, 2003. For revision April 29, 2003. Accepted July 15, 2003. Current affiliations: Department of Gastroenterology and Hepa- tology, Westmead Hospital, City West Endoscopy, Westmead, Australia. Abstract presentation at Digestive Diseases Week, May 19-23, 2002, San Francisco, California (Gastrointest Endosc 2002;55:W1616). Abstract presentation at Australian Gastroenterology Week, September 23-27, 2001, Sydney, Australia (J Gastroenterol Hepatol 2001;16(Suppl):A42). Reprint requests: Michael J Bourke, MBBS, FRACP, Citywest Gastroenterology, 106A/151 Hawkesbury Rd., Westmead, Syd- ney, Australia 2145. Copyright Ó 2003 by the American Society for Gastrointestinal Endoscopy 0016-5107/2003/$30.00 + 0 PII:S0016-5107(03)02017-0 VOLUME 58, NO. 5, 2003 GASTROINTESTINAL ENDOSCOPY 685