Computed tomographic evaluation of laryngotracheal trauma

Tracheal trauma in rhesus macaques (Macaca mulatta)

Tracheal disruption is a previously unreported complication of nonhuman primate social trauma. Two cases were identified in rhesus macaques with subcutaneous emphysema. These cases resolved with medical management and demonstrate that the combined use of radiography and tracheoscopy allows rapid assessment and diagnosis of tracheal trauma in nonhuman primates.

Management of tracheobronchial injuries

Tracheobronchial injury is one of cases which are relatively uncommon, but must be suspected to make the diagnosis and managed immediately. In such a case, primary initial goals are to stabilize the airway and localize the injury and then determine its extend. These can be possible mostly with flexible bronchoscopy conducted by a surgeon who can repair the injury. Most of the penetrating injuries occur in the cervical region. On the other hand, most of the blunt injuries occur in the distal trachea and right main bronchus and they can be best approached by right posterolateral thoracotomy. The selection of the manner and time of approaching depends on the existence and severity of additional injuries. Most of the injuries can be restored by deploying simple techniques such as individual sutures, while some of them requires complex reconstruction techniques. Apart from paying attention to the pulmonary toilet, follow-up is crucial for determination of anastomotic technique or stenosis. Conservative treatment may be considered an option with a high probability of success in patients meeting the criteria, especially in patients with iatrogenic tracheobronchial injury.

[Surgery of traumatic tracheal and tracheobronchial injuries]

Tracheal injuries are altogether rare events and can be divided into three broad categories: tracheobronchial injuries caused by external violence, iatrogenic ruptures of the trachea and inhalation trauma. Successful management of tracheobronchial injuries requires a fast and straightforward diagnostic evaluation. In all severely injured patients with cervicothoracic involvement an injury of the tracheobronchial system should be actively excluded. Although it is commonly agreed that posttraumatic injuries require surgical intervention the management of iatrogenic injuries is presently shifting towards a more conservative treatment.

Traumatic injury to the trachea and bronchus

Tracheobronchial injuries are relatively uncommon, often require a degree of clinical suspicion to make the diagnosis, and usually require immediate management. The primary initial goals are twofold: stabilize the airway and define the extent and location of injury. These are often facilitated by flexible bronchoscopy, in the hands of a surgeon capable of managing these injuries. Most penetrating injuries occur in the cervical area. Most blunt injuries occur in the distal trachea or right mainstem, and are best approached by a right posterolateral thoracotomy. Choice and timing of approach are dictated by the presence and severity of associated injuries. The mainstay of intraoperative management remains a single-lumen endotracheal tube. Most injuries can be repaired by simple techniques, using interrupted sutures, but some require complex reconstructive techniques. Follow-up to detect stenosis or anastomotic technique is important, as is attention to pulmonary toilet.

Using CT to diagnose tracheal rupture

OBJECTIVE

A retrospective study was performed to assess CT sensitivity for diagnosing tracheal rupture. Intubated cadaver tracheas were examined to assess endotracheal tube balloon overdistention and deformity and to evaluate the relationship of balloon pressures to tracheal injury.

MATERIALS AND METHODS

Neck or chest CT scans of 14 patients with tracheal rupture and 41 control trauma patients with pneumomediastinum but without tracheal injury were reviewed and compared to assess the presence and location of extrapulmonary air, whether direct visualization of tracheal wall disruption was possible, the size and shape of endotracheal tube balloon, signs of transtracheal balloon herniation in intubated patients, and the location of the extratracheal endotracheal tube. Intact and experimentally injured cadaver tracheas were used to evaluate tube balloon pressure and configuration.

RESULTS

All 14 patients with tracheal rupture had deep cervical air and pneumomediastinum. Overdistention of the tube balloon occurred in 71% (5/7) of the intubated patients, and balloon herniation occurred in 29% (2/7). Direct tracheal injury was seen in 71% (10/14) of the patients as a wall defect (n = 8) or deformity (n = 2). Overall, CT was 85% sensitive for detecting tracheal injury. Patients with tracheal injury had a significantly lower incidence of pneumothorax (p = 0.01) than did the control group. The CT appearance of balloon herniation through defects in the cadaver tracheas closely mimicked those of patients with tracheal injury. The amount of balloon pressure required to rupture the intubated trachea was extremely high and rupture was difficult to obtain.

CONCLUSION

CT can reveal tracheal injury and can be used to select trauma patients with pneumomediastinum for bronchoscopy, leading to early confirmation and treatment.

Nonaortic mediastinal injuries from blunt chest trauma

In addition to traumatic aortic injuries (TAI), blunt chest trauma may damage other structures in the mediastinum, including the tracheobronchial tree, the heart and pericardium, and rarely the esophagus. Tracheobronchial injuries may be difficult to separate radiographically from accompanying parenchymal lung injuries. Experience with diagnosis by computed tomography (CT) is still limited. Cardiac injuries often require emergent surgery before extensive imaging can be done. Some patients, usually those with chamber ruptures of the right heart, survive long enough to receive a chest CT, at which time hemopericardium can be detected. Upper esophageal injuries may occur in conjunction with lower cervical or upper thoracic spine injures. Distal esophageal injuries are rarely caused by blunt trauma.