Multicompartment Injury Risk in High-Rate Nonpenetrating Blunt Thoracic Impacts

The occurrence of blunt abdominal injuries resulting from thoracic high-rate nonpenetrating blunt impacts (NPBIs) is often missed and associated with increased mortality and morbidity. Diagnosis of penetrating gunshot wounds successfully predicts injury locations using bullet trajectory, but no similar correlation has been applied for blunt impacts. Historically, thoracic NPBIs have been studied on ovine subjects and have reported thoracic only and thoracoabdominal injuries for impacts at the same location. The purpose of this study is to investigate if the finite element ovine thorax model (FE-OTM) can indicate changes in multicompartment injury risk based on impact angle and determine a method for measuring this change. Twelve thoracic NPBIs were run over six impact angles (0-25 deg). Tissue directly under the impactor and along the path of impact was analyzed for changes in composition and strain. Tissue composition analysis identified abdominal, lung, and liver as key tissue types. Cumulative volume analysis was used to determine a combined strain-volume metric for regions of interest (ROIs). Within each region, Spearman's rank correlation was used to determine the strength of the relationship between this metric and impact angle. The key tissues experienced very strong correlations with impact angles and directionalities that corresponded to their change in volume. In conclusion, the FE-OTM can be used to indicate changes to multicompartment injury risk based on impact angle. A first principal strain-volume based metric in the key tissue types is recommended.