title: The evidence based dilemma of intraperitoneal drainage for pancreatic resection - a systematic review and meta-analysis.
abstract: BACKGROUND
  Routine placement of intraperitoneal drains has been shown to be ineffective or potentially harmful in various abdominal surgical procedures. Studies assessing risks and benefits of abdominal drains for pancreatic resections have demonstrated inconsistent results. We thus performed a systematic review of the literature and meta-analyzed outcomes of pancreatic resections with and without intraoperative placement of drains.
  
  
  METHODS
  A database search according to the PRISMA guidelines was performed for studies on pancreatic resection with and without intraperitoneal drainage. The subgroup 'pancreaticoduodenectomy' was analyzed separately. The quality of studies was assessed using the MINORS and STROBE criteria. Pooled estimates of morbidity, mortality and length of hospital stay were calculated using random effects models.
  
  
  RESULTS
  Only two randomized trials were identified. Their results were contradictory. We thus included six further, retrospective studies in the meta-analysis. However, with I2 = 68% for any kind of complication, the estimate of inter-study heterogeneity was high. While overall morbidity after any kind of pancreatic resection was lower without drains (p = 0.04), there was no significant difference in mortality rates. In contrast, pooled estimates of outcomes after pancreaticoduodenectomy demonstrated no differences in morbidity (p = 0.40) but increased rates of intraabdominal abscesses (p = 0.04) and mortality (p = 0.04) without intraperitoneal drainage.
  
  
  CONCLUSIONS
  Although drains are associated with slightly increased morbidity for pancreatic resections, routine omission of drains cannot be advocated, especially after pancreaticoduodenectomy. While selective drainage seems reasonable, further efforts to generate more reliable data are questionable because of the current studies and the presumed small differences in outcomes.
  
  
  BACKGROUND
  Systematic review registration number CRD42014007497.
authors.forename: Ulrich
authors.initials: U
authors.lastname: Nitsche
authors.forename: Tara C
authors.initials: TC
authors.lastname: Müller
authors.forename: Christoph
authors.initials: C
authors.lastname: Späth
authors.forename: Lynne
authors.initials: L
authors.lastname: Cresswell
authors.forename: Dirk
authors.initials: D
authors.lastname: Wilhelm
authors.forename: Helmut
authors.initials: H
authors.lastname: Friess
authors.forename: Christoph W
authors.initials: CW
authors.lastname: Michalski
authors.affiliation: Department of Surgery, Klinikum rechts der Isar, Technische Universität München, Ismaninger Strasse 22, 81675 Munich, Germany. kleeff@tum.de.
authors.forename: Jörg
authors.initials: J
authors.lastname: Kleeff
mesh_terms: D003657:Decision Making; D004322:Drainage / Q000379:methods*; D019317:Evidence-Based Medicine / Q000379:methods*; D006801:Humans; D010180:Pancreatectomy / Q000379:methods*; D010195:Pancreatitis / Q000601:surgery*; D010529:Peritoneal Cavity / Q000601:surgery*