title: The efferent segment in continent cutaneous urinary diversion: a comprehensive review of the literature.
abstract: OBJECTIVE
  To critically assess the biophysical properties and current status of outlet formation in heterotopic intestinal urinary diversion. As despite three decades of clinical experience with continent cutaneous urinary diversion through bowel segments, no consensus has been reached for the optimal efferent segment although its function largely determines patient satisfaction.
  
  
  METHODS
  A comprehensive Medline literature search using the Medical Subject Headings database (search terms: continent urinary diversion followed by either efferent segment, nipple, Mitrofanoff, Yang-Monti, Benchekroun, tapered ileum, intussuscepted ileum, Kock pouch, T-valve, or Ghonheim) was conducted to identify all full-length original articles addressing the various principles and techniques of outlet formation as well as their outcomes and complications. Examined series were published in English between 1966 and 2010. All studies were systematically evaluated using a checklist (study design, number of patients, etc.) and rated according to the Oxford Centre for Evidence-Based Medicine Levels of Evidence (LoE).
  
  
  RESULTS
  While there was a continuous flow of publications over the last three decades, the vast majority of studies were retrospective case series with numerous confounding factors and poorly defined, non-standardized outcomes (LoE, 3). Only a few investigations compare different efferent segments (LoE, 2a). No randomized studies exist. The major biophysical principles are based on the use of flap, nipple, and hydraulic valves. Vermiform appendix, intussuscepted ileal nipple, and the Yang-Monti tube are the most popular techniques and have well-established data on outcomes, complications, and failure rates. Artificial sphincter systems and tissue engineering have provided disappointing results thus far. Most reconstructive strategies are subject to a process of on-going improvement.
  
  
  CONCLUSIONS
  The continuous quest for optimization has not led to a single universally applicable efferent segment in continent cutaneous urinary diversion. While all techniques have their unique set of advantages and disadvantages, they will always remain a compromise. Success depends on selecting the optimal strategy for individual patients. A major change in principles in the near future is unlikely.
authors.affiliation: Department of Urology, Albert-Ludwigs-University Medical School, Freiburg, Germany. peter.ardelt@uniklinik-freiburg.de
authors.forename: Peter U
authors.initials: PU
authors.lastname: Ardelt
authors.forename: Christopher R J
authors.initials: CR
authors.lastname: Woodhouse
authors.forename: Hubertus
authors.initials: H
authors.lastname: Riedmiller
authors.forename: Elmar W
authors.initials: EW
authors.lastname: Gerharz
mesh_terms: D019317:Evidence-Based Medicine; D006304:Health Status; D006801:Humans; D007082:Ileum / Q000601:surgery; D011788:Quality of Life; D013524:Surgical Flaps; D014547:Urinary Diversion / Q000379:methods*; D016476:Urinary Reservoirs, Continent