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Open Access Open Badges Research article

Does the variable-stiffness colonoscope makes colonoscopy easier? A meta-analysis of the efficacy of the variable stiffness colonoscope compared with the standard adult colonoscope

Qin Xie1, Bin Chen1, Liu Liu1 and Huatian Gan2*

Author Affiliations

1 Department of Gastroenterology, West China Hospital of Sichuan University, Chengdu, Sichuan Province, 610041, China

2 Department of Geriatric Medicine and Gastroenterology, West China Hospital of Sichuan University, Chengdu, Sichuan Province, 610041, China

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BMC Gastroenterology 2012, 12:151  doi:10.1186/1471-230X-12-151

Published: 24 October 2012



The variable-stiffness colonoscope (VSC) appears to have advantages over the standard adult colonoscope (SAC), although data are conflicting. To provide a comprehensive up-to-date review, we conducted a meta-analysis to compare the efficacies of the VSC and SAC.


Electronic databases, including PubMed, EMBASE, the Cochrane library and the Science Citation Index, were searched to retrieve relevant trials. In addition, meeting abstracts and the reference lists of retrieved articles were reviewed for further relevant studies.


Eight randomized controlled trials (RCTs), enrolling a total of 2033 patients, were included in the meta-analysis. There was no significant heterogeneity among these studies. The cecal intubation rate was higher with the use of VSC (RR = 1.03, 95% CI 1.01 to 1.06, 8 RCTs). The VSC was also associated with fewer position changes made during colonoscopy. Time to cecal intubation was similar with VSC and SAC (WMD −0.54, 95% CI −1.40 to 0.32) but shorter in subgroup analysis with the use of VSC (WMD = −1.36, 95% CI −2.29 to −0.43). Sedation dose used with the two types of instruments showed no evidence of differences either. For all trials, only patients were blinded because of the nature of the interventions.


Use of the VSC significantly improved the cecal intubation rate and reduced ancillary maneuvers made during the procedure. Cecal intubation time was similar for the two colonoscope types over all trials, whereas a shortened time with the use of the adult VSC was seen in subgroup analysis.

Colonoscope; Variable-stiffness colonoscope; Stiffness; Meta-analysis