title: Technical improvement using ultra-slim gastroscopes for direct peroral cholangioscopy: analysis of the initial learning phase.
abstract: BACKGROUND
  Direct peroral cholangioscopy (POCS) is an emerging technique complementing endoscopic retrograde cholangiopancreatography (ERCP). Only few data about the learning process of this technique exist. The objective of this study is to investigate the learning process of POCS in a tertiary center.
  
  
  METHODS
  The study was a single center observational trial. All patients were investigated with standard ERCP directly prior to cholangioscopy. The bile ducts were intubated using the balloon anchor technique. The learning process was analyzed using linear regression and cumulative sum analysis.
  
  
  RESULTS
  A total of 42 POCS were performed. Intubation was successful in 38/42 (90%). Reasons for failed intubation were small caliber bile ducts, duodenal diverticulum and papillary adenoma. Failed intubation occurred three times in the first half and only one time in the second half of investigations. The mean intubation time was 8.4 ± 4.9 min (1.6-23 min). The average intubation time changed over time (R(2) = -0.7) from 9.5 min in the first half investigations to 7.3 min in the second half procedures. Cumulative sum analysis revealed an initial learning process of nine investigations with significant variations in results followed by a steady improvement in the following investigations.
  
  
  CONCLUSIONS
  Direct POCS is a useful tool for the investigation of biliary disease, which demands a short but recognizable initial learning phase even for experienced endoscopists.
authors.affiliation: Department of Gastroenterology, Hepatology and Infectious Diseases, Otto-von-Guericke University, Leipziger Str. 44, 39120, Magdeburg, Germany. jochen.weigt@med.ovgu.de.
authors.forename: Jochen
authors.initials: J
authors.lastname: Weigt
authors.forename: Arne
authors.initials: A
authors.lastname: Kandulski
authors.forename: Peter
authors.initials: P
authors.lastname: Malfertheiner
mesh_terms: D002760:Cholangiopancreatography, Endoscopic Retrograde / Q000295:instrumentation*; D016145:Endoscopy, Digestive System / Q000193:education*; D004867:Equipment Design; D005260:Female; D005705:Gallbladder Diseases / Q000175:diagnosis*; D020699:Gastroscopes; D006801:Humans; D059032:Learning Curve; D008297:Male; D012189:Retrospective Studies
keywords: Cholangioscopy; Direct peroral cholangioscopy; Learning