Related Experiment Video
Updated: Jul 10, 2026
The Role of Indocyanine Green Fluorescence in Complex Laparoscopic Cholecystectomy Navigation
Published on: January 31, 2025
Preoperative Conversion Risk Score for Acute Calculous Cholecystitis: Does TG18 Add Value?
Rahman Şenocak1, Murat Özkara2, Şahin Kaymak1
1Department of General Surgery, Gulhane School of Medicine, University of Health Sciences, Ankara, Türkiye.
Introduction:
The 2018 Tokyo Guidelines are widely used for the diagnosis and severity grading of acute calculous cholecystitis, but their value for individualized prediction of conversion from laparoscopic to open cholecystectomy remains uncertain. We aimed to develop a practical preoperative model and point-based score and to compare their performance with guideline grade alone.
Materials And Methods:
This single-center retrospective cohort study included 183 adults who underwent laparoscopic cholecystectomy for acute calculous cholecystitis between May 2020 and May 2024. Twenty-five prespecified preoperative candidate predictors across clinical, laboratory, and imaging findings were evaluated using univariable effect estimation and multivariable Firth penalized logistic regression. Three approaches were assessed: a clinical model, guideline grade alone, and a hybrid model. A deterministic point-based conversion risk score was derived from the final multivariable model using age, diabetes mellitus, WBC, LDH, and gallbladder wall thickness.
Results:
Conversion to open surgery occurred in 33 of 183 patients (18.0%). Diabetes mellitus, age, white blood cell count, gallbladder wall thickness, and lactate dehydrogenase remained independently associated with conversion. The hybrid and clinical models showed strong internal discrimination, whereas guideline grade alone performed poorly (area under the curve 0.927 and 0.931 versus 0.576). The derived score also showed good discrimination (area under the curve 0.893; Brier score 0.082), but adding guideline grade did not improve performance (area under the curve 0.891; Brier score 0.081; likelihood ratio P = 0.442; DeLong P = 0.212). Despite this, grade-specific thresholds identified marked within-grade heterogeneity: conversion rates were 0.0% versus 41.7% in grade I and 4.3% versus 60.0% in grade II.
Conclusions:
A simple preoperative conversion risk score based on age, diabetes mellitus, WBC, LDH, and gallbladder wall thickness provided more informative patient-level prediction than TG18 alone, while TG18 primarily supported within-grade clinical interpretation rather than meaningful incremental global discrimination.
