title: Study protocol of the DUCATI-study: a randomized controlled trial investigating the optimal common channel length in laparoscopic gastric bypass for morbid obese patients.
abstract: BACKGROUND
  Morbid obesity has become one of the most frequent chronic medical disorders in Western countries, affecting 1.5-2 % of the Dutch population. Currently, the laparoscopic Roux-Y gastric bypass is considered to be the most effective bariatric treatment option for morbid obesity as it results in adequate weight loss and a significant decrease in comorbidity. Although this technique has been applied for years, the optimal lengths of the three bowel limbs (alimentary limb, biliopancreatic limb, and common channel) in order to achieve maximal percentage excess weight loss with minimal side effects (i.e. malabsorption symptoms), are unknown. As 'normal' sized gastric bypasses achieve an average of 60 - 80 % excess weight loss after one year, one could hypothesize that afferent limb lengths should be longer in order to reduce the common channel length, thereby improving outcome in terms of excess weight loss. The aim of the current study is to investigate the effect of the length of the common channel in gastric bypass surgery for morbid obesity. In this randomized controlled trial the very long Roux limb gastric bypass will be compared to the standard gastric bypass, in order to conclude which option is the optimal therapeutic strategy in the morbidly obese patient.
  
  
  METHODS
  In this multicentre trial patients will be randomized either to a very long Roux limb gastric bypass with a fixed common channel length of 100 cm, or to a standard gastric bypass with a variable common channel length. The primary objective is to evaluate whether the very long Roux limb gastric bypass is superior in terms of percentage excess weight loss after one year follow-up compared to the standard gastric bypass. Secondary endpoints are quality-of-life, cure /improvement of obesity related comorbidity, complications, malnutrition, re-admission rate, and re-operation rate.
  
  
  CONCLUSIONS
  We hypothesize that our proposed distal LRYGB will provide for improved results concerning % EWL with an acceptable rate of (metabolic) complications. Our main point of interest is to determine if the distal LRYGB is a superior alternative to standard LRYGB in terms of percentage excess weight loss and to put more focus on the role of the common channel. Therefore we will perform this randomized controlled trial comparing both techniques, with % EWL as a primary outcome.
  
  
  BACKGROUND
  CCMO registration number: NL43951.101.13 and Netherlands Trial Registry number: NTR4466.
authors.affiliation: Department of Surgery, Sint Franciscus Gasthuis, Rotterdam, The Netherlands.
authors.forename: Ralph P M
authors.initials: RP
authors.lastname: Gadiot
authors.affiliation: Department of Surgery, Erasmus MC, Rotterdam, The Netherlands.
authors.forename: Brechtje A
authors.initials: BA
authors.lastname: Grotenhuis
authors.affiliation: Department of Surgery, Sint Franciscus Gasthuis, Rotterdam, The Netherlands.
authors.forename: L Ulas
authors.initials: LU
authors.lastname: Biter
authors.affiliation: Department of Surgery, Sint Franciscus Gasthuis, Rotterdam, The Netherlands.
authors.forename: Martin
authors.initials: M
authors.lastname: Dunkelgrun
authors.affiliation: Department of Surgery, Sint Franciscus Gasthuis, Rotterdam, The Netherlands.
authors.forename: Hans J J
authors.initials: HJ
authors.lastname: Zengerink
authors.affiliation: Department of Bariatric Surgery, Lievensberg Ziekenhuis, Bergen op Zoom, The Netherlands.
authors.forename: Pierre B G M
authors.initials: PB
authors.lastname: Feskens
authors.affiliation: Department of Surgery, Sint Franciscus Gasthuis, Rotterdam, The Netherlands.
authors.forename: Guido H H
authors.initials: GH
authors.lastname: Mannaerts
keywords: Bariatric surgery; Common channel; Laparoscopic Roux -Y gastric bypass; Morbid obesity