Application of Ultrasonography for Blunt Laryngo-Cervical-Tracheal Injury

Background: Bronchoscopy has been the gold standard for diagnosing blunt laryngo-cervical-tracheal injury (BLCTI); however, BLCTI is often undetected. Ultrasonography (US) is an indispensable tool in the field of critical care and traumatology, but has not been considered useful for evaluation of the airway. The aim of this study was to determine the usefulness of US in the diagnosis of BLCTI. Methods: To determine the detectability of BLCTI by US, we use a model of cylindrical plastic with a protruding mass made of paste. The model was placed in a water bath and US (3.5-MHz probe) was used to try to detect the mass. Results: We could detect the existence of the mass as a high echoic mass with strongly high echoic tail. We used four patients with BLCTIs whose sites of injury were confirmed by computed tomography (CT) and bronchoscopy. We evaluated the larynx and the cervical trachea as their outline of air in the cranial section near the sternal notch using a 3.5-MHz convex probe. The following US findings were compared with CT and bronchoscopic images as specific findings of BLCTI: discontinuity of the laryngo-cervical-tracheal wall and an abnormal mass protruding into the laryngo-cervical-tracheal lumen. Specific findings of BLCTI were detected in three of the four patients, whose sites of injury were the anterior or lateral side of the larynx or the cervical trachea. The site of injury of the remaining patient, where we detected no specific BLCTI findings, was the posterior wall of the larynx. Conclusions: US is useful for the diagnosis of BLCTI because it is capable of presenting specific images showing BLCTI features such as discontinuity of the laryngo-cervical-tracheal wall and abnormal masses protruding into the lumen; not only as a single diagnostic tool but one tool with many uses.