Predicting conversion from laparoscopic to open cholecystectomy presented as a probability nomogram based on preoperative patient risk factors.

BACKGROUND: We aim to develop a risk stratification tool to preoperatively predict conversion (CONV) from a laparoscopic to open cholecystectomy.

METHODS: Multiple risk factors were analyzed with multivariate logistic regression and presented as probability nomograms.

RESULTS: Of 732 patients, 47 (6.4%) required CONV. Among 40 preoperative risk factors evaluated, 5 variables were found to have significant association with CONV: 2 clinical variables, previous upper abdominal surgery (odds ratio [OR] 95.2) and obesity defined as body mass index greater than 30 kg/m(2) (OR 12.3), and 3 ultrasound parameters, visible choledocholithiasis (OR 19.8), impacted stone at the neck of the gallbladder (OR 5.9), and gallbladder wall width in millimeters (OR 2.1). Nomograms based on this multivariate model demonstrate the individual preoperative probability of CONV. Internal validation using receiver operator curve analysis showed an area under the curve of .97.

CONCLUSION: Four probability nomograms were developed as a practical individual risk stratification tool to predict probability of CONV.