External validation of the Cairns Prediction Model (CPM) to predict conversion from laparoscopic to open cholecystectomy.

BACKGROUND: Valid and user-friendly prediction models for conversion to open cholecystectomy allow for proper planning prior to surgery. The Cairns Prediction Model (CPM) has been in use clinically in the original study site for the past three years, but has not been tested at other sites. METHODS: A retrospective, single-centred study collected ultrasonic measurements and clinical variables alongside with conversion status from consecutive patients who underwent laparoscopic cholecystectomy from 2013 to 2016 in The Townsville Hospital, North Queensland, Australia. An area under the curve (AUC) was calculated to externally validate of the CPM. RESULTS: Conversion was necessary in 43 (4.2%) out of 1035 patients. External validation showed an area under the curve of 0.87 (95% CI 0.82-0.93, p = 1.1 × 10-14). CONCLUSIONS: In comparison with most previously published models, which have an AUC of approximately 0.80 or less, the CPM has the highest AUC of all published prediction models both for internal and external validation.

Risk factors for conversion of laparoscopic cholecystectomy to open surgery - A systematic literature review of 30 studies.

BACKGROUND: The study aims to evaluate the methodological quality of publications relating to predicting the need of conversion from laparoscopic to open cholecystectomy and to describe identified prognostic factors. METHOD: Only English full-text articles with their own unique observations from more than 300 patients were included. Only data using multivariate analysis of risk factors were selected. Quality assessment criteria stratifying the risk of bias were constructed and applied. RESULTS: The methodological quality of the studies were mostly heterogeneous. Most studies performed well in half of the quality criteria and considered similar risk factors, such as male gender and old age, as significant. Several studies developed prediction models for risk of conversion. Independent risk factors appeared to have additive effects. CONCLUSION: A detailed critical review of studies of prediction models and risk stratification for conversion from laparoscopic to open cholecystectomy is presented. One study is identified of high quality with a potential to be used in clinical practice, and external validation of this model is recommended.