A New Preoperative Scoring System to Predict Difficulty of Laparoscopic Cholecystectomy and Risk of Conversion to Open Surgery

Abstract

To develop a preoperative scoring model to assess difficulty of laparoscopic cholecystectomy (LC) and risk of conversion to open cholecystectomy (OC), retrospective analysis of patients who underwent elective LC and LC converted to OC between 01/06/2013 and 01/06/2014. LC difficulty assessment was based on operative time (OT) and conversion to OC. Preoperative factors included age; ultrasound scan (USS) findings; “gallbladder (GB) wall thickness; other acute inflammatory signs, e.g. pericholecystic fluid collection, common bile duct (CBD) diameter, and size of gallstones (GS)”; previous pancreatitis; endoscopic retrograde cholangiopancreatography (ERCP) or magnetic resonance cholangiopancreatography (MRCP). Preoperative weighted score for LC difficulty was formulated based on the degree of significance of preoperative factors. A total of 280 patients were included, and 3.9% had open conversion. Univariate analysis revealed highly significant (HS) association between prolonged OT and USS findings, thick GB wall (P = 0.003) and other acute inflammatory signs (P = 0.0001). Significant (S) association with pancreatitis (P = 0.05), ERCP (P = 0.027) and MRCP (P = 0.016). Conversion to OC had HS association with thick GB wall (P = 0.001) and other acute inflammatory signs (P = 0.0001), S association with age > 62.3 (P = 0.015) and large GS (P = 0.035). Score was formulated as follows: 2 points for HS factors on the multivariate analysis (thick GB wall and other acute inflammatory signs) (P = 0.027 and 0.007, respectively) and 1 point for each S factor (age > 62, large GS, pancreatitis and ERCP/MRCP). Sensitivity and specificity using ROC curve showed that patients scoring < 2 had a straightforward LC with OT < 63 min and no conversions to OC; score ≥ 2 had a difficult LC with prolonged OT ≥63 min (sensitivity 46%, specificity 70%, P = 0.03) but no conversion to OC, and score ≥ 4 had more difficult LC with OT ≥63 min and with possible conversions to OC (sensitivity 73%, specificity 87%, P = 0.001). The scoring system could be helpful in preoperative planning to improve efficiency of theatre time, better utilisation of day surgery lists and assignment of the appropriate surgical grade/experience.