腹腔鏡下胆嚢摘出術における変換のリスク因子と予測ノモグラムの開発

BackgroundLaparoscopic cholecystectomy (LC) is the gold standard for gallbladder disease, yet conversion to open cholecystectomy (OC) remains necessary in 2-15% of cases. Although often life-saving, conversion increases operative time, morbidity, and hospital stay. Identifying reliable predictors is therefore crucial for surgical planning and patient counseling.MethodsA retrospective cohort study was conducted on 4535 patients who underwent LC at a tertiary center between January 2018 and May 2024. Demographic, clinical, laboratory, radiological, intraoperative, and histopathological data were extracted from medical records. Univariate and multivariate logistic regression analyses were used to identify independent predictors of conversion. A nomogram was developed to estimate individualized conversion risk.ResultsConversion to OC occurred in 304 patients (6.7%). Independent predictors included male sex (OR 1.65, 95% CI 1.09-2.50), ASA IV classification (OR 4.84, 95% CI 2.51-9.33), elevated CRP (OR 1.007 per mg/L, 95% CI 1.004-1.010), reduced lymphocyte count (OR 0.42, 95% CI 0.21-0.84), gastric or intestinal complications (OR 3.38, 95% CI 1.01-11.38), gangrenous gallbladder (OR 2.39, 95% CI 1.45-3.93), and xanthogranulomatous cholecystitis (OR 5.42, 95% CI 1.61-18.25). Gallbladder wall thickness was the strongest preoperative predictor (OR 1.20 per mm, 95% CI 1.13-1.27, P < 0.001), and existence of dense adhesions were the strongest intraoperative predictor (OR 26.77, 95% CI 16.64-43.07).ConclusionConversion to OC reflects anatomical complexity and advanced disease rather than surgical failure. Gallbladder wall thickness, inflammatory markers, adhesions, gangrene, and xanthogranulomatous cholecystitis are consistent predictors. The proposed nomogram provides individualized risk estimation to improve preoperative planning and patient counseling. Prospective multicenter validation is warranted.