Predictive score for conversion in laparoscopic cholecystectomy - a prospective study.

Objective: 2-15% of laparoscopic cholecystectomy gets converted to an open procedure due to various factors. The aim of this study was to identify pre-operative risk factors that could predict the conversion of laparoscopic cholecystectomy to open surgery. Pre-operative prediction would help in reducing the morbidity.

Material and methods: Adult patients undergoing elective laparoscopic cholecystectomy at a tertiary institute were included in the study. The parameters analysed were age, gender, body mass index, total count, liver function test, gall bladder size and wall thickness, impacted stone in Hartmann's pouch and common bile duct (CBD) diameter on ultrasonography. Intra-operative findings and the total number of conversions to open surgery were documented. Statistical analysis was done using SPSS 16.0 Inc., IBM system. A univariate regression analysis was used to find the significant risk factors followed by multivariate linear regression.

Results: Twenty-one of the 222 (9.5%) patients who underwent laparoscopic cholecystectomy, were converted to open cholecystectomy. Six variables were found significant on univariate analysis: Age, sex, total count, gallbladder wall thickness and size and diameter of the CBD. On logistic regression analysis, gall bladder wall thickness and size were found to be significant, and were used in the scoring system, wherein 1 point was given to each variable. The predicted risk of conversion was 0.5%, 1.8% and 7.2% for a score of zero, one and two respectively.

Conclusion: The most significant factors predicting conversion of laparoscopic cholecystectomy to open surgery were gall bladder size and wall thickness. This prediction can be used to minimize the time to conversion and reduce the morbidity.