title: The Clavien-Dindo classification of surgical complications: five-year experience.
abstract: OBJECTIVE
  The lack of consensus on how to define and grade adverse postoperative events has greatly hampered the evaluation of surgical procedures. A new classification of complications, initiated in 1992, was updated 5 years ago. It is based on the type of therapy needed to correct the complication. The principle of the classification was to be simple, reproducible, flexible, and applicable irrespective of the cultural background. The aim of the current study was to critically evaluate this classification from the perspective of its use in the literature, by assessing interobserver variability in grading complex complication scenarios and to correlate the classification grades with patients', nurses', and doctors' perception.
  
  
  METHODS
  Reports from the literature using the classification system were systematically analyzed. Next, 11 scenarios illustrating difficult cases were prepared to develop a consensus on how to rank the various complications. Third, 7 centers from different continents, having routinely used the classification, independently assessed the 11 scenarios. An agreement analysis was performed to test the accuracy and reliability of the classification. Finally, the perception of the severity was tested in patients, nurses, and physicians by presenting 30 scenarios, each illustrating a specific grade of complication.
  
  
  RESULTS
  We noted a dramatic increase in the use of the classification in many fields of surgery. About half of the studies used the contracted form, whereas the rest used the full range of grading. Two-thirds of the publications avoided subjective terms such as minor or major complications. The study of 11 difficult cases among various centers revealed a high degree of agreement in identifying and ranking complications (89% agreement), and enabled a better definition of unclear situations. Each grade of complications significantly correlated with the perception by patients, nurses, and physicians (P < 0.05, Kruskal-Wallis test).
  
  
  CONCLUSIONS
  This 5-year evaluation provides strong evidence that the classification is valid and applicable worldwide in many fields of surgery. No modification in the general principle of classification is warranted in view of the use in ongoing publications and trials. Subjective, inaccurate, or confusing terms such as "minor or major" should be removed from the surgical literature.
authors.affiliation: Department of Surgery and Swiss HPB Center, University Hospital of Zurich, Switzerland. clavien@chir.uzh.ch
authors.forename: Pierre A
authors.initials: PA
authors.lastname: Clavien
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Barkun
authors.forename: Michelle L
authors.initials: ML
authors.lastname: de Oliveira
authors.forename: Jean Nicolas
authors.initials: JN
authors.lastname: Vauthey
authors.forename: Daniel
authors.initials: D
authors.lastname: Dindo
authors.forename: Richard D
authors.initials: RD
authors.lastname: Schulick
authors.forename: Eduardo
authors.initials: E
authors.lastname: de Santibañes
authors.forename: Juan
authors.initials: J
authors.lastname: Pekolj
authors.forename: Ksenija
authors.initials: K
authors.lastname: Slankamenac
authors.forename: Claudio
authors.initials: C
authors.lastname: Bassi
authors.forename: Rolf
authors.initials: R
authors.lastname: Graf
authors.forename: René
authors.initials: R
authors.lastname: Vonlanthen
authors.forename: Robert
authors.initials: R
authors.lastname: Padbury
authors.forename: John L
authors.initials: JL
authors.lastname: Cameron
authors.forename: Masatoshi
authors.initials: M
authors.lastname: Makuuchi
mesh_terms: D001291:Attitude of Health Personnel; D006801:Humans; D015588:Observer Variation; D017060:Patient Satisfaction; D011183:Postoperative Complications / Q000145:classification*; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012720:Severity of Illness Index; D009626:Terminology as Topic