The role of computed tomography angiography in the detection of aerodigestive tract injury following penetrating neck injury

The purpose of this study was to audit our experience with computed tomography angiography (CTA) for the detection of aerodigestive tract injury (ADTI) following penetrating neck injury (PNI) and to assess the significance of deep surgical emphysema on CTA. A prospectively maintained trauma registry at the Pietermaritzburg Metropolitan Trauma Service, Pietermaritzburg, South Africa was retrospectively interrogated. The data of all patients with PNI investigated with CTA over a 4-y period were reviewed. All findings of deep surgical emphysema were correlated to an aggregate standard of reference for ADTI as demonstrated by results from clinical examination, surgical neck exploration, endoscopy or contrasted swallow to determine the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of this finding. A total of 383 patients underwent a CTA for PNI. A total of 94 vascular injuries were identified on 78 positive CTA studies. The sensitivity and specificity of CTA in detecting a vascular injury were 94.4% and 96.7%. Of the 383 patients investigated a total of 38 patients were diagnosed with digestive tract injury (DTI), and all of these patients were found to have deep surgical emphysema on CTA, except for one patient with a clinically insignificant oral cavity injury. Another 126 patients also had deep surgical emphysema on CTA but no DTI. The sensitivity, specificity, PPV, and NPV of deep surgical emphysema for the diagnosis of confirmed DTI in PNI were therefore 97.4%, 63.5%, 22.7%, and 99.5%, respectively. The sensitivity and NPV were, however, 100% when clinically insignificant injuries were excluded. Including patients with confirmed airway injuries and excluding all patients with pneumothoraces yielded a sensitivity, specificity, PPV, and NPV of 94.1%, 71.9%, 30.0%, and 98.9%, respectively, for the identification of ADTI. When excluding surgically irrelevant injuries, the sensitivity and NPV were again both 100%. CTA for PNI has a high sensitivity and specificity for demonstrating vascular injury. The absence of deep surgical emphysema in the deep cervical fascial planes virtually excludes surgically significant ADTI. The presence of deep surgical emphysema is nonspecific but warrants further investigation.