Incremental value of laboratory and ultrasonographic markers for preoperative risk stratification of difficult laparoscopic cholecystectomy: a cross-validated cohort study
- 1Sancaktepe Şehit Prof. Dr. İlhan Varank Training and Research Hospital, Republic of Türkiye Ministry of Health, University of Health Sciences, Istanbul, Türkiye
Abstract
Background: Difficult laparoscopic cholecystectomy (LC) is associated with prolonged operative times, bile duct injuries, and increased postoperative morbidity. Reliable preoperative prediction could optimize surgical planning and patient consent, but the incremental value of adding laboratory and ultrasonographic (USG) data to routinely available clinical variables has rarely been quantified.
Materials and methods: We conducted a retrospective cohort study of 648 consecutive patients undergoing LC for symptomatic gallstone disease, reported in accordance with the STROCSS 2021 guidelines and relevant TRIPOD recommendations. Difficult LC was defined a priori as a composite outcome (operative time ≥90 min, subtotal cholecystectomy, conversion to open surgery, fundus-first dissection, or additional ports), capturing distinct but overlapping dimensions of operative difficulty ranging from prolonged dissection to surgeon-driven bailout strategies. Independent predictors were identified by multivariable logistic regression, and discriminative performance of clinical, clinical + laboratory, and combined (clinical + laboratory + USG) models was assessed using fivefold cross-validated receiver operating characteristic analysis, with bootstrap-derived 95% confidence intervals (CIs), calibration, and bootstrap optimism correction.
Results: Difficult LC occurred in 125 patients (19.3%). Impacted stone [adjusted odds ratio (OR) 2.86, 95% CI 1.66–4.92], previous cholecystitis attack (OR 1.87, 95% CI 1.15–3.02), gallbladder wall thickness (OR 1.74 per mm, 95% CI 1.36–2.21), body mass index (OR 1.05 per kg/m2, 95% CI 1.00–1.11), and C-reactive protein (OR 1.02 per mg/L, 95% CI 1.01–1.04) were independent predictors (all p < 0.05). Cross-validated areas under the receiver operating characteristic curve (AUC) values increased progressively from 0.723 (95% CI 0.687–0.786) (clinical) to 0.734 (95% CI 0.700–0.796) (clinical + laboratory) to 0.768 (95% CI 0.742–0.831) (combined + USG), a pattern preserved after excluding operative time from the outcome definition [0.705 (95% CI 0.635–0.801) → 0.716 (95% CI 0.641–0.808) → 0.739 (95% CI 0.675–0.832)]. The paired-bootstrap increment in AUC was +0.011 (95% CI −0.007 to +0.040) for laboratory variables and +0.034 (95% CI +0.010 to +0.071) for ultrasonographic variables, indicating that the laboratory increment alone was not statistically distinguishable from zero, whereas the ultrasonographic increment was. The combined model showed acceptable calibration (slope 0.76, intercept 0.03, Brier score 0.134) and an optimism-corrected AUC of 0.783. Difficult LC was associated with more postoperative bile leaks, 30-day readmissions, and longer hospital stays (all p < 0.001).
Conclusion: Sequentially adding laboratory and then ultrasonographic data to a clinical-only model produced modest, calibration-confirmed improvements in cross-validated discrimination of difficult LC. This increment was statistically robust for ultrasonographic variables (95% CI excluding zero) but not for laboratory variables alone, indicating a modest incremental improvement in discrimination rather than a clinically transformative gain. External, prospective validation is warranted before routine clinical implementation.
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BibTeX
@article{basdogan2026incremental,
title = {{Incremental value of laboratory and ultrasonographic markers for preoperative risk stratification of difficult laparoscopic cholecystectomy: a cross-validated cohort study}},
author = {Mustafa Kağan Başdoğan and Furkan Saydın and Cem Batuhan Ofluoğlu and Güney Özkaya and Fırat Mülküt},
journal = {Frontiers in Surgery},
year = {2026},
month = oct,
doi = {10.3389/fsurg.2026.1982578},
url = {https://doi.org/10.3389/fsurg.2026.1982578},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Incremental value of laboratory and ultrasonographic markers for preoperative risk stratification of difficult laparoscopic cholecystectomy: a cross-validated cohort study
AU - Mustafa Kağan Başdoğan
AU - Furkan Saydın
AU - Cem Batuhan Ofluoğlu
AU - Güney Özkaya
AU - Fırat Mülküt
PY - 2026
DA - 2026/10/13
JO - Frontiers in Surgery
DO - 10.3389/fsurg.2026.1982578
UR - https://doi.org/10.3389/fsurg.2026.1982578
AB - Background: Difficult laparoscopic cholecystectomy (LC) is associated with prolonged operative times, bile duct injuries, and increased postoperative morbidity. Reliable preoperative prediction could optimize surgical planning and patient consent, but the incremental value of adding laboratory and ultrasonographic (USG) data to routinely available clinical variables has rarely been quantified. Materials and methods: We conducted a retrospective cohort study of 648 consecutive patients undergoing LC for symptomatic gallstone disease, reported in accordance with the STROCSS 2021 guidelines and relevant TRIPOD recommendations. Difficult LC was defined a priori as a composite outcome (operative time ≥90 min, subtotal cholecystectomy, conversion to open surgery, fundus-first dissection, or additional ports), capturing distinct but overlapping dimensions of operative difficulty ranging from prolonged dissection to surgeon-driven bailout strategies. Independent predictors were identified by multivariable logistic regression, and discriminative performance of clinical, clinical + laboratory, and combined (clinical + laboratory + USG) models was assessed using fivefold cross-validated receiver operating characteristic analysis, with bootstrap-derived 95% confidence intervals (CIs), calibration, and bootstrap optimism correction. Results: Difficult LC occurred in 125 patients (19.3%). Impacted stone [adjusted odds ratio (OR) 2.86, 95% CI 1.66–4.92], previous cholecystitis attack (OR 1.87, 95% CI 1.15–3.02), gallbladder wall thickness (OR 1.74 per mm, 95% CI 1.36–2.21), body mass index (OR 1.05 per kg/m2, 95% CI 1.00–1.11), and C-reactive protein (OR 1.02 per mg/L, 95% CI 1.01–1.04) were independent predictors (all p < 0.05). Cross-validated areas under the receiver operating characteristic curve (AUC) values increased progressively from 0.723 (95% CI 0.687–0.786) (clinical) to 0.734 (95% CI 0.700–0.796) (clinical + laboratory) to 0.768 (95% CI 0.742–0.831) (combined + USG), a pattern preserved after excluding operative time from the outcome definition [0.705 (95% CI 0.635–0.801) → 0.716 (95% CI 0.641–0.808) → 0.739 (95% CI 0.675–0.832)]. The paired-bootstrap increment in AUC was +0.011 (95% CI −0.007 to +0.040) for laboratory variables and +0.034 (95% CI +0.010 to +0.071) for ultrasonographic variables, indicating that the laboratory increment alone was not statistically distinguishable from zero, whereas the ultrasonographic increment was. The combined model showed acceptable calibration (slope 0.76, intercept 0.03, Brier score 0.134) and an optimism-corrected AUC of 0.783. Difficult LC was associated with more postoperative bile leaks, 30-day readmissions, and longer hospital stays (all p < 0.001). Conclusion: Sequentially adding laboratory and then ultrasonographic data to a clinical-only model produced modest, calibration-confirmed improvements in cross-validated discrimination of difficult LC. This increment was statistically robust for ultrasonographic variables (95% CI excluding zero) but not for laboratory variables alone, indicating a modest incremental improvement in discrimination rather than a clinically transformative gain. External, prospective validation is warranted before routine clinical implementation.
SN - 2296-875X
ER -