title: Variable stiffness colonoscopes are associated with less pain during colonoscopy in unsedated patients.
abstract: OBJECTIVE
  Application of a new variable stiffness colonoscope (VSC) is expected to control loop formation and to lessen patient discomfort. The aim of this prospective study was to compare the efficacy of VSC with a conventional colonoscope (CC) in unsedated colonoscopy, based on the experience of examiners.
  
  
  METHODS
  Four-hundred sixty-seven patients were randomly assigned to undergo colonoscopy with either VSC or CC by an endoscopist, including experienced and less-experienced examiners. The percentages of completed procedure and time to cecal intubation were recorded. Patients were asked to rate pain on a 5-point pain score.
  
  
  RESULTS
  The percentages of completed procedure with VSC and CC were 98% and 95%, respectively, by less-experienced hands, and 99% and 98%, respectively, by experienced hands. Time for cecal intubation with VSC and CC was 15.7 and 18.5 min, respectively, by less-experienced hands, and 9.8 and 10.6 min, respectively, by experienced hands. A significantly lower mean pain score was noted in VSC patients compared with CC patients, irrespective of experience of the examiner. The percent of patients rating the procedure as moderately or severely painful was significantly lower with VSC than with CC, both in less-experienced (19% vs 40%; p < 0.01) and experienced hands (15% vs 26%; p < 0.05).
  
  
  CONCLUSIONS
  Our results indicated that VSC allows favorable examination compared with CC regarding completeness, time to cecal intubation, and comfort of patients undergoing unsedated colonoscopy, irrespective of the examiner's experience. These features suggest VSC as the preferred colonoscope for patients undergoing unsedated colonoscopy.
authors.affiliation: Third Department of Internal Medicine, University of Occupational and Environmental Health, Japan, School of Medicine, Kitakyushu, Japan.
authors.forename: Ichiro
authors.initials: I
authors.lastname: Yoshikawa
authors.forename: Hidekazu
authors.initials: H
authors.lastname: Honda
authors.forename: Kaori
authors.initials: K
authors.lastname: Nagata
authors.forename: Kikuo
authors.initials: K
authors.lastname: Kanda
authors.forename: Takuji
authors.initials: T
authors.lastname: Yamasaki
authors.forename: Keiichiro
authors.initials: K
authors.lastname: Kume
authors.forename: Akinari
authors.initials: A
authors.lastname: Tabaru
authors.forename: Makoto
authors.initials: M
authors.lastname: Otsuki
mesh_terms: D000368:Aged; D002983:Clinical Competence; D020685:Colonoscopes; D003113:Colonoscopy / Q000009:adverse effects*; D004867:Equipment Design; D005260:Female; D006801:Humans; D006993:Hypnotics and Sedatives; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D010146:Pain / Q000209:etiology* / Q000503:physiopathology*; D010147:Pain Measurement; D011446:Prospective Studies
chemical_list: D006993:Hypnotics and Sedatives