title: Criteria for definition of a complex abdominal wall hernia.
abstract: OBJECTIVE
  A clear definition of "complex (abdominal wall) hernia" is missing, though the term is often used. Practically all "complex hernia" literature is retrospective and lacks proper description of the population. There is need for clarification and classification to improve patient care and allow comparison of different surgical approaches. The aim of this study was to reach consensus on criteria used to define a patient with "complex" hernia.
  
  
  METHODS
  Three consensus meetings were convened by surgeons with expertise in complex abdominal wall hernias, aimed at laying down criteria that can be used to define "complex hernia" patients, and to divide patients in severity classes. To aid discussion, literature review was performed to identify hernia classification systems, and to find evidence for patient and hernia variables that influence treatment and/or prognosis.
  
  
  RESULTS
  Consensus was reached on 22 patient and hernia variables for "complex" hernia criteria inclusion which were grouped under four categories: "Size and location", "Contamination/soft tissue condition", "Patient history/risk factors", and "Clinical scenario". These variables were further divided in three patient severity classes ('Minor', 'Moderate', and 'Major') to provide guidance for peri-operative planning and measures, the risk of a complicated post-operative course, and the extent of financial costs associated with treatment of these hernia patients.
  
  
  CONCLUSIONS
  Common criteria that can be used in defining and describing "complex" (abdominal wall) hernia patients have been identified and divided under four categories and three severity classes. Next step would be to create and validate treatment algorithms to guide the choice of surgical technique including mesh type for the various complex hernias.
authors.affiliation: Department of Surgery, Radboud University Nijmegen Medical Centre, P.O. Box 9101, 6500 HB, Nijmegen, The Netherlands, n.slater.md@gmail.com.
authors.forename: N J
authors.initials: NJ
authors.lastname: Slater
authors.forename: A
authors.initials: A
authors.lastname: Montgomery
authors.forename: F
authors.initials: F
authors.lastname: Berrevoet
authors.forename: A M
authors.initials: AM
authors.lastname: Carbonell
authors.forename: A
authors.initials: A
authors.lastname: Chang
authors.forename: M
authors.initials: M
authors.lastname: Franklin
authors.forename: K W
authors.initials: KW
authors.lastname: Kercher
authors.forename: B J
authors.initials: BJ
authors.lastname: Lammers
authors.forename: E
authors.initials: E
authors.lastname: Parra-Davilla
authors.forename: S
authors.initials: S
authors.lastname: Roll
authors.forename: S
authors.initials: S
authors.lastname: Towfigh
authors.forename: E
authors.initials: E
authors.lastname: van Geffen
authors.forename: J
authors.initials: J
authors.lastname: Conze
authors.forename: H
authors.initials: H
authors.lastname: van Goor
mesh_terms: D046449:Hernia, Abdominal / Q000145:classification* / Q000473:pathology / Q000601:surgery; D006801:Humans; D010347:Patient Care Planning; D012008:Recurrence; D012307:Risk Factors; D012720:Severity of Illness Index; D013526:Surgical Mesh; D009626:Terminology as Topic