Development and Validation of a Preoperative Risk Score for Difficult Laparoscopic Cholecystectomy: A Retrospective Study in Resource-Limited Settings

Description

Study Design and Setting This single-center retrospective observational cohort study analyzed data from Ibb University Hospitals. We reviewed surgical and radiological records of consecutive patients undergoing laparoscopic cholecystectomy from April 22, 2020, to November 23, 2024. Ethical Approval The Ibb University Institutional Research Ethics Committee approved the protocol on January 1, 2025 (Ref: IBBUNI.2025.1.001). Individual consent was waived given the anonymized, retrospective design, following Declaration of Helsinki principles. Patient Population We screened adults (≥18 years) with laparoscopic cholecystectomy for benign gallbladder disease (acute/chronic cholecystitis, symptomatic cholelithiasis). Exclusions: gallbladder malignancy, combined hepatobiliary/pancreatic procedures, or incomplete records. Final cohort: 301 patients (STARD Flow Diagram, Supplementary Figure 1). Data Collection A trained team extracted preoperative data via standardized electronic forms: demographics (age, sex), BMI, clinical history (prior acute cholecystitis, comorbidities), physical exam (RUQ rigidity), labs (WBC count), and ultrasound (gallbladder wall thickness, impacted stone at neck/cystic duct). Primary Outcome "Difficult LC" was a composite: (1) intraoperative conversion to open surgery, or (2) major complication (significant biliary/vascular/visceral injury). Of 384 procedures, 57 (14.8%) were difficult. Statistical Analysis Analyses used Python 3.10 (SciPy, pandas, scikit-learn, statsmodels). Continuous data: mean±SD or median (IQR) per Shapiro-Wilk test. Comparisons: t/Mann-Whitney U tests (continuous), χ²/Fisher's exact (categorical). Model Development Variables with p<0.10 univariately entered multivariable logistic regression (VIF<2.0, linearity checked). Final model by AIC, p<0.05, clinical relevance. β-coefficients derived integer risk score (divide by smallest β, round). Assessed: AUC (bootstrapped 95% CI, 1000 reps), calibration (Brier score, plot), DCA for utility. Bootstrap internal validation.

Steps to reproduce

Methods A trained team prospectively collected preoperative, intraoperative, and postoperative data using a standardized electronic form. This included demographics, clinical history, physical exam findings (notably RUQ rigidity), preoperative WBC count, and ultrasound details (gallbladder wall thickness, impacted stone). Primary Outcome: A "difficult laparoscopic cholecystectomy" was a composite of conversion to open surgery or a major intraoperative complication (e.g., significant biliary or vascular injury). 57 of 384 cases (14.8%) were difficult. Statistical Analysis: Analyses used Python. Group comparisons employed appropriate tests (t-test, Mann-Whitney U, Chi-squared). Variables with a univariate association of *p* < 0.10 were entered into a multivariable logistic regression model to identify independent predictors. Model assumptions were checked, including multicollinearity (VIF < 2.0). Model & Risk Score: The final model, selected via clinical relevance, significance (*p* < 0.05), and AIC, was used to create an integer-based risk score. The model's and score's discrimination were assessed using the AUC (with bootstrapped 95% CI). Calibration was checked with a plot and Brier score. Clinical utility was evaluated via Decision Curve Analysis, and internal validation used bootstrap resampling for an optimism-corrected AUC.

Institutions

• Ibb University

  Ibb

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