Excluding Hollow Viscus Injury for Abdominal Seat Belt Sign Using Computed Tomography

Abstract

Abdominal seat belt sign (SBS) has historically entailed admission and observation because of the diagnostic limitations of computed tomography (CT) imaging and high rates of hollow viscus injury (HVI). Recent single-institution, observational studies have questioned the utility of this practice. To evaluate whether a negative CT scan can safely predict the absence of HVI in the setting of an abdominal SBS. This prospective, observational cohort study was conducted in 9 level I trauma centers between August 2020 and October 2021 and included adult trauma patients with abdominal SBS. Inclusion in the study required abdominal CT as part of the initial trauma evaluation and before any surgical intervention, if performed. Results of CT scans were considered positive if they revealed any of the following: abdominal wall soft tissue contusion, free fluid, bowel wall thickening, mesenteric stranding, mesenteric hematoma, bowel dilation, pneumatosis, or pneumoperitoneum. Presence of HVI diagnosed at the time of operative intervention. A total of 754 patients with abdominal SBS had an HVI prevalence of 9.2% (n = 69), with only 1 patient with HVI (0.1%) having a negative CT (ie, none of the 8 a priori CT findings). On bivariate analysis comparing patients with and without HVI, there were significant associations between each of the individual CT scan findings and the presence of HVI. The strongest association was found with the presence of free fluid, with a more than 40-fold increase in the likelihood of HVI (odds ratio [OR], 42.68; 95% CI, 20.48-88.94; P < .001). The presence of free fluid also served as the most effective binary classifier for presence of HVI (area under the receiver operator characteristic curve [AUC], 0.87; 95% CI, 0.83-0.91). There was also an association between a negative CT scan and the absence of HVI (OR, 41.09; 95% CI, 9.01-727.69; P < .001; AUC, 0.68; 95% CI, 0.66-0.70). The prevalence of HVI among patients with an abdominal SBS and negative findings on CT is extremely low, if not zero. The practice of admitting and observing all patients with abdominal SBS should be reconsidered when a high-quality CT scan is negative, which may lead to significant resource and cost savings.