Development and Internal Validation of a Preoperative Risk Stratification Model for Difficult Laparoscopic Cholecystectomy in Acute Cholecystitis

Background

Difficult laparoscopic cholecystectomy (DLC) in patients with acute cholecystitis (AC) is associated with greater operative complexity and increased perioperative morbidity, yet reliable preoperative risk stratification remains limited. This study aimed to develop and internally validate a preoperative prediction model for DLC and to compare its predictive performance with that of an alternative C-reactive protein–albumin–lymphocyte (CALLY)-based model. Materials and Methods: We retrospectively analyzed consecutive adult patients who underwent laparoscopic cholecystectomy (LC) for AC at a single center between 1 January 2022 and 31 December 2025. DLC was defined as operative time >90 min, conversion to open surgery, subtotal cholecystectomy or a Nassar grade ≥4. Preoperative clinical, laboratory and ultrasonographic variables were evaluated using multivariable logistic regression. Model performance was assessed by discrimination, calibration, Brier score, decision curve analysis and bootstrap internal validation.