Background: Laparoscopic cholecystectomy has become the standard operative procedure for cholelithiasis, but there are still some patients requiring conversion to open cholecystectomy mainly because of technical difficulty. Our aim was to develop a risk score for prediction of conversion from laparoscopic to open cholecystectomy.

Methods: Preoperative clinical, laboratory, and radiologic parameters of 1,000 patients who underwent laparoscopic cholecystectomy were analyzed for their effect on conversion rates. Six parameters (male sex, abdominal tenderness, previous upper abdominal operation, sonographically thickened gallbladder wall, age over 60 years, preoperative diagnosis of acute cholecystitis) were found to have significant effect in multivariate analysis. A constant and coefficients for these variables were calculated and formed the risk score.

Results: Overall 48 patients required conversion to open cholecystectomy (4.8%). These patients had significantly higher scores (mean 6.9 versus −7.2, P <0.001). Increasing scores resulted with significant increases in conversion rates and probabilities (P <0.001). Ideal cut-off point for this score was −3; conversion rate was 1.6% under −3, but 11.4% over this value (P <0.001).

Conclusions: Conversion risk can be predicted easily by this score. Patients having high risk may be informed and scheduled appropriately. An experienced surgeon has to operate on these patients, and he or she has to make an early decision to convert in case of difficulty.