Tears of the trachea and main bronchi caused by blunt trauma: radiologic findings.

Although most of the radiologic changes that have been described in transection or laceration of the trachea or main bronchi are nonspecific, they can be of diagnostic importance in the appropriate clinical setting. In order to reassess the significance of these findings, and to determine the presence of any other changes that might lead to a definitive diagnosis, we retrospectively reviewed the chest radiographs of nine patients who had tears or transection of the trachea and/or main bronchi as a result of blunt chest trauma. The diagnosis was proved by bronchoscopy in all patients and reconfirmed at surgery in five. The predominant findings on the chest radiographs were related to air leak and included subcutaneous emphysema (seven patients), pneumomediastinum (seven patients), pneumothorax (six patients), and air surrounding a bronchus in one patient. Upper thoracic fractures that involved the clavicles, scapula, sternum, and ribs were present in four patients. Abnormalities in the appearance of an endotracheal tube in two patients (overdistention of the cuff or extraluminal position of the tip), and the presence of the fallen lung sign (collapse of the lung toward the lateral chest wall) in two others provided specific evidence of tracheobronchial injury. We conclude that, although the major importance of the chest radiograph in patients with tracheobronchial transection may be to verify the existence of air leak, the presence of the fallen lung sign and endotracheal tube abnormalities is a reliable indication of airway injury.