Thoracic Trauma

Abstract

Clinically significant thoracic trauma occurs in 4–6% of injured children. Although the frequency of penetrating injuries continues to increase in both urban and rural centers, injuries due to blunt trauma, primarily from motor vehicle crashes and pedestrian trauma, predominate, accounting for more than 85% of cases. Isolated thoracic injuries are rare in children, and instead occur much more commonly in association with multi-system trauma. When present, they are a marker for severe, life threatening injuries. In fact, regardless of the mechanism, an associated thoracic injury more than triples the risk of death. Data from the National Pediatric Trauma Registry reports an overall mortality of 15% for children with blunt thoracic injury.

Appendices

Summary Points

• Because most injuries are the result of blunt mechanisms, associated injuries are common and impact outcome.

• Immaturity of the bony thoracic cage allows for significant internal injury to occur without external signs.

• Most pneumothoraces and hemothoraces can be managed by tube thoracostomy.

• Rib fractures and thoracic duct injury, in the absence of a defined mechanism, should raise concerns for child abuse.

• Most pulmonary and cardiac contusions can be managed supportively.

• Determination of ballistic trajectory helps identify organ injury.

Editor’s Comment

The life-threatening injuries that we commonly see in adults after a blunt thoracic trauma mechanism are rarely seen or significantly less morbid in children: aortic dissection, myocardial contusion, pericardial tamponade, pulmonary contusion, sternal fracture, and flail chest physiology. Children appear to less vulnerable to these types of injuries perhaps due to superior tissue resiliency and durability, more favorable dissipation of kinetic energy due to size/volume differences, and, in the case of a head-on automobile collision, the absence of steering wheel-induced injuries. Nevertheless, these injuries are occasionally seen in children and a proper diagnostic algorithm should be followed whenever the mechanism is suggestive.

After blunt trauma, a CT scan of the chest will sometimes reveal a small amount of mediastinal air or a tiny pneumothorax. In the absence of other signs of significant organ injury, these findings can generally be regarded as incidental. Nevertheless, these patients warrant a meticulous evaluation and careful observation.

Penetrating injuries in the form of stabbings and gun shot wounds are becoming more common in children and require a thoughtful and scrupulous diagnostic approach in order to identify latent injuries. Trajectories based on the location of entry and exit wounds are notoriously inaccurate for several reasons: the victim might have been in a contorted position at the moment of impact, missiles can follow tissue planes and therefore fail to travel in a straight line, and bullets can ricochet within the bony cage of the thorax. Not every patient with a gunshot wound or knife injury to the chest will require an operation, perhaps because most patients with potentially operative injuries never make it to the hospital, but a trauma surgeon needs to be involved with every aspect of the care of these children. The most important diagnostic and therapeutic maneuver in a child with a gunshot wound to the chest is the placement of a chest tube. The stable child with a stab wound should have a chest radiograph and could potentially avoid a chest tube if there is no evidence of a pneumo- or hemothorax. Placing a chest tube in a child should be done with a delicate technique, under sterile conditions, and after sedation and injection of a local anesthetic. In young children, a small incision that passes through the chest wall obliquely is all that is necessary (not big enough to insert your finger) but it is surprisingly easy to inadvertently place the tube into the subcutaneous tissues and for it to erroneously appear to be in perfect position on a chest film.

The primary indication for operative intervention in the child with a thoracic injury is bleeding. There is no absolute amount of bloody chest tube effluent that can be used to decide if an operation is needed; this must be based on good judgment. Lung injuries can be oversewn or repaired with stapling device using a vascular cartridge. Esophageal injuries can almost always be repaired primarily provided there is little devitalized tissue and good drainage can be maintained. The same is true for most tracheal injuries, but when there are injuries to both the airway and the esophagus, viable tissue should be placed between the two suture lines to prevent the formation of a tracheo-esophageal fistula. The vagus and phrenic nerves should be carefully identified and protected throughout the procedure. Major vascular injuries should be repaired using standard vascular techniques, including the principle of proximal and distal control of the vessels and the use of side-biting clamps whenever feasible.

Diagnostic Studies

Anterior-posterior plain radiograph

Helical computed tomography

Computed tomography angiography

Transthoracic echocardiogram

Transesophageal echocardiogram

Contrast esophagram

12-lead electrocardiogram

Parental Preparation

• Possible major operation, large incision, long recovery

• High rates of morbidity and mortality

• Delayed operations may be necessary

Preoperative Preparation

• Type and cross

• Informed consent

Technical Points

• Tube thoracostomy is by same technique employed for adults

• Pulmonary injury may require debridement, wedge resection, tractotomy, lobectomy or pneumonectomy

• Enteral administration of cream may facilitate identification of thoracic duct injury

• A positive pericardial window (blood) mandates sternotomy and formal pericardial and cardiac exploration

• Esophageal perforations identified early may be managed with primary repair and drainage, late injuries (greater than 24 h) may require esophageal diversion