Predicting Strangulation Risk in Acute Irreducible Inguinal Hernias: Development and Validation of an Integrated Model Using Inflammatory Markers and Imaging Features

Purpose

Accurately predicting strangulation risk in acute irreducible inguinal hernia remains a clinical challenge. This study aimed to develop and validate an integrated model using routinely available inflammatory markers and imaging features for preoperative risk assessment.

Methods

We conducted a retrospective cohort study of adults with acute irreducible inguinal hernia at a single center (January 2020–August 2024). Predictors were drawn from clinical, laboratory (including inflammatory indices) and imaging domains. We employed a three-stage analytical framework: (1) univariate screening with t-tests or Mann–Whitney U tests, (2) variable refinement using LASSO regression on significant univariate predictors, and (3) definitive model construction via multivariable logistic regression. Model performance was evaluated by its area under the curve (AUC), calibration (calibration plot and Hosmer–Lemeshow test), and clinical utility (net benefit on decision curve analysis, DCA). Model stability was assessed through 10-fold cross-validation and 1000 bootstrap internal validations.

Results

From 988 screened hernia patients, 84 met the inclusion criteria. The intraoperative findings confirmed bowel strangulation in 40 patients (47.6%). The final model, the Inguinal Hernia Strangulation Risk Score (IHS-RS), incorporated five independent predictors: pelvic effusion (odds ratio [OR]: 8.77), age cohort (OR: 2.12), femoral hernia (vs. nonfemoral) (OR: 2.28), neutrophil count (OR: 1.26), and blood urea nitrogen (OR: 1.19). The model showed strong discrimination with an apparent AUC of 0.847 (95% CI: 0.762–0.933) and an internally validated AUC of 0.790 on 10-fold cross-validation, good calibration (Hosmer–Lemeshow test p = 0.809), and provided a positive net clinical benefit across a range of threshold probabilities on DCA.

Conclusion

The IHS-RS, integrating five readily available preoperative variables, offers a practical tool for preoperative risk stratification. It has the potential to aid surgical planning and optimize triage and referral decisions for frontline clinicians managing acute irreducible inguinal hernia.