title: Risk Factors for Conversion of Laparoscopic Cholecystectomy to Open Surgery: A New Predictive Statistical Model.
abstract: BACKGROUND
  Although laparoscopic cholecystectomy is currently the standard treatment for benign gallbladder pathologies, some cases still require conversion to open cholecystectomy. Since open cholecystectomy has a significantly higher morbidity rate and a lengthier stay in the hospital compared with laparoscopic surgery, predicting this conversion would grant a great advantage in the management of cholecystitis. Therefore, in this study, we aimed to develop a predictive statistical model.
  
  
  METHODS
  Between August 2006 and January 2011, 1335 laparoscopic cholecystectomies were initiated at the General Surgery Department of Hacettepe University. One hundred four of these cases were started as laparoscopic surgeries, but converted to open cholecystectomies. In our study, we randomly chose 104 laparoscopically completed cases and compared them with the 104 converted cases. We used 31 parameters, including demographics, ultrasonographic findings, and laboratory values, to compare groups. These parameters were later included in a logistic regression analysis to create a statistical model that predicts conversion to open cholecystectomy.
  
  
  RESULTS
  Among the 1335 laparoscopically started cases, 104 (7.7%) were converted to open surgery. In our study, we found age, gender, ultrasonographic findings of acute cholecystitis, history of choledocolithiasis, history of abdominal surgery, and alkaline phosphatase (ALP) levels to be significant risk factors. By using a receiver operating characteristic curve, we found that the risk significantly increases after 55 years of age and an ALP over 80 IU/L.
  
  
  CONCLUSIONS
  Using four parameters-age, gender, history of abdominal surgery, and ALP-in our statistical model, we were able to predict the conversion from laparoscopic to open cholecystectomy with 70% sensitivity and 79% specificity.
authors.affiliation: 1 Department of General Surgery, Hacettepe University , Ankara, Turkey .
authors.forename: Kemal
authors.initials: K
authors.lastname: Beksac
authors.affiliation: 1 Department of General Surgery, Hacettepe University , Ankara, Turkey .
authors.forename: Nihan
authors.initials: N
authors.lastname: Turhan
authors.affiliation: 2 Department of Biostatistics, Hacettepe University , Ankara, Turkey .
authors.forename: Ergun
authors.initials: E
authors.lastname: Karaagaoglu
authors.affiliation: 1 Department of General Surgery, Hacettepe University , Ankara, Turkey .
authors.forename: Osman
authors.initials: O
authors.lastname: Abbasoglu
mesh_terms: D000005:Abdomen / Q000601:surgery; D000328:Adult; D000367:Age Factors; D000368:Aged; D000469:Alkaline Phosphatase / Q000097:blood; D016022:Case-Control Studies; D017081:Cholecystectomy, Laparoscopic / Q000009:adverse effects*; D002764:Cholecystitis / Q000000981:diagnostic imaging / Q000601:surgery; D041881:Cholecystitis, Acute / Q000601:surgery; D042883:Choledocholithiasis / Q000150:complications; D061887:Conversion to Open Surgery; D005260:Female; D006801:Humans; D007431:Intraoperative Complications / Q000209:etiology / Q000601:surgery; D010535:Laparoscopy; D007902:Length of Stay; D008297:Male; D008875:Middle Aged; D015233:Models, Statistical; D012372:ROC Curve; D012307:Risk Factors; D012737:Sex Factors; D014463:Ultrasonography
chemical_list: D000469:Alkaline Phosphatase