title: Preoperative risk factors for conversion from laparoscopic to open cholecystectomy: a validated risk score derived from a prospective U.K. database of 8820 patients.
abstract: Laparoscopic cholecystectomy is commonly performed, and several factors increase the risk of open conversion, prolonging operating time and hospital stay. Preoperative stratification would improve consent, scheduling and identify appropriate training cases. The aim of this study was to develop a validated risk score for conversion for use in clinical practice.
  
  
  
  Preoperative patient and disease-related variables were identified from a prospective cholecystectomy database (CholeS) of 8820 patients, divided into main and validation sets. Preoperative predictors of conversion were identified by multivariable binary logistic regression. A risk score was developed and validated using a forward stepwise approach.
  
  
  
  Some 297 procedures (3.4%) were converted. The risk score was derived from six significant predictors: age (p = 0.005), sex (p < 0.001), indication for surgery (p < 0.001), ASA (p < 0.001), thick-walled gallbladder (p = 0.040) and CBD diameter (p = 0.004). Testing the score on the validation set yielded an AUROC = 0.766 (p < 0.001), and a score >6 identified patients at high risk of conversion (7.1% vs. 1.2%).
  
  
  
  This validated risk score allows preoperative identification of patients at six-fold increased risk of conversion to open cholecystectomy.
authors: Liver Unit, University Hospitals Birmingham NHS Foundation Trust, Birmingham, UK. Electronic address: robert.sutcliffe@uhb.nhs.uk.
authors: Robert P
authors: RP
authors: Sutcliffe
authors: West Midlands Research Collaborative, Academic Department of Surgery, Birmingham University, UK.
authors: Marianne
authors: M
authors: Hollyman
authors: Institute of Translational Medicine, University Hospitals Birmingham NHS Foundation Trust, Birmingham, UK.
authors: James
authors: J
authors: Hodson
authors: Liver Unit, University Hospitals Birmingham NHS Foundation Trust, Birmingham, UK.
authors: Glenn
authors: G
authors: Bonney
authors: Nottingham Oesophago-Gastric Unit, Nottingham University Hospitals NHS Foundation Trust, Nottingham, UK.
authors: Ravi S
authors: RS
authors: Vohra
authors: Department of Upper Gastrointestinal Surgery, University Hospitals Birmingham NHS Foundation Trust, Birmingham, UK.
authors: Ewen A
authors: EA
authors: Griffiths
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D016009:Chi-Square Distribution; D017081:Cholecystectomy, Laparoscopic / Q000009:adverse effects*; D003135:Common Bile Duct / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery*; D061887:Conversion to Open Surgery; D016208:Databases, Factual; D004066:Digestive System Diseases / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery*; D004108:Dilatation, Pathologic; D005260:Female; D005704:Gallbladder / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery*; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D016017:Odds Ratio; D011237:Predictive Value of Tests; D011446:Prospective Studies; D015203:Reproducibility of Results; D018570:Risk Assessment; D012307:Risk Factors; D012737:Sex Factors; D016896:Treatment Outcome; D006113:United Kingdom