Predictors of acute incisional hernia incarceration at initial hernia diagnosis on computed tomography

Abstract

BACKGROUND Acute incisional hernia incarceration is associated with high morbidity and mortality yet there is little evidence to guide which patients will benefit most from prophylactic repair. We explored baseline computed tomography (CT) characteristics associated with incarceration. METHODS A case-control study design was utilized to explore adults (≥18 years) diagnosed with an incisional hernia between 2010 and 2017 at a single institution with a 1-year minimum follow-up. Computed tomography imaging at the time of initial hernia diagnosis was examined. Following propensity score matching for baseline characteristics, multivariable logistic regression was performed to identify independent predictors associated with acute incarceration. RESULTS A total of 532 patients (27.26% male, mean 61.55 years) were examined, of whom 238 experienced an acute incarceration. Between two well-matched cohorts with and without incarceration, the presence of small bowel in the hernia sac (odds ratio [OR], 7.50; 95% confidence interval [CI], 3.35–16.38), increasing sac height (OR, 1.34; 95% CI, 1.10–1.64), more acute hernia angle (OR, 0.98 per degree; 95% CI, 0.97–0.99), decreased fascial defect width (OR, 0.68; 95% CI, 0.58–0.81), and greater outer abdominal fat (OR, 1.28; 95% CI, 1.02–1.60) were associated with acute incarceration. Using threshold analysis, a hernia angle of <91 degrees and a sac height of >3.25 cm were associated with increased incarceration risk. CONCLUSION Computed tomography features present at the time of hernia diagnosis provide insight into later acute incarceration risk. Improved understanding of acute incisional hernia incarceration can guide selection for prophylactic repair and thereby may mitigate the excess morbidity associated with incarceration. LEVEL OF EVIDENCE Prognostic and Epidemiological; Level III.