title: [The impact of preoperative classification of expected intraoperative difficulties. A multicenter study].
abstract: BACKGROUND
  This study examined the validity of the classification of intraoperative difficulties and its usefulness in surgical practice.
  
  
  METHODS
  Data on general surgical patients were collected in four German hospitals within a multicentre validation study. Before and immediately after surgery, the operating surgeon rated the relative difficulty of the operation using a score of 1 (easy), 2 (not easy), 3 (difficult) and 4 (very difficult). Data on the duration of surgery and on the occurrence of intraoperative and postoperative complications were collected. Multivariate regression models were constructed to examine whether different clinical variables and the surgeon's preoperative assessment of surgical difficulty increased the power of the prognostic model. The R(2) statistics, which describe explained variance (EV) as a percentage was used to compare regression models.
  
  
  RESULTS
  From July 2010 to August 2011 overall 500 patients were analyzed. Most patients were classified as being ideal (30 %) or relatively ideal (49 %) candidates for surgery. Preoperative and postoperative classification results were identical in 64 % of patients and were partly determined by classical risk factors (ASA score, number of previous surgeries, type of surgery, body mass index and gender). The addition of the surgeon's risk estimation to the multivariate models improved the prediction of duration of surgery (from 41.4% to 45.5 % EV), complications (from 22.5% to 24.5 % EV) and length of stay (from 32.6% to 34.5 % EV).
  
  
  CONCLUSIONS
  The classification of intraoperative difficulty can be applicable in surgical daily practice in terms of surgical decision-making in difficult intraoperative situations as well as in operating room management. It could also be useful for other surgical disciplines.
authors.affiliation: Abteilung für Allgemein-und Visceralchirurgie, Klinikum Werra-Meißner, Elsa-Brändström-Str. 1, 37269, Eschwege, Deutschland, michael.korenkov@klinikum-wm.de.
authors.forename: M
authors.initials: M
authors.lastname: Korenkov
authors.forename: M
authors.initials: M
authors.lastname: Gundlach
authors.forename: J
authors.initials: J
authors.lastname: Heimbucher
authors.forename: S
authors.initials: S
authors.lastname: Saad
authors.forename: H
authors.initials: H
authors.lastname: Troidl
authors.forename: H
authors.initials: H
authors.lastname: Zühlke
mesh_terms: D000328:Adult; D000368:Aged; D003661:Decision Support Techniques; D005260:Female; D005858:Germany; D006305:Health Status Indicators; D006801:Humans; D007431:Intraoperative Complications / Q000145:classification* / Q000209:etiology; D007902:Length of Stay / Q000706:statistics & numerical data; D008297:Male; D008875:Middle Aged; D015233:Models, Statistical; D015999:Multivariate Analysis; D061646:Operative Time; D011183:Postoperative Complications / Q000145:classification* / Q000209:etiology; D011300:Preoperative Care / Q000379:methods*; D011379:Prognosis; D013514:Surgical Procedures, Operative / Q000145:classification*
vernacular_title: Stellenwert einer präoperativen Klassifikation erwarteter intraoperativer Schwierigkeiten : Eine multizentrische Studie.