Katrina A. Leone
PATHOPHYSIOLOGY
The neck contains a high concentration of vascular, aerodigestive, and spinal structures in a relatively confined space.
The platysma is the most superficial structure beneath the skin. Penetrating injuries that violate the platysma require evaluation for deep structure injuries.
Beneath the platysma is the deep cervical fascia that creates a series of tight fascial compartments. A tam-ponade effect within these compartments limits the potential for external bleeding from vascular injuries, but can result in airway compression and compromise.
CLINICAL FEATURES
All signs and symptoms associated with neck trauma require diagnostic evaluation, but hard signs are more often associated with significant injury than soft signs (Table 165-1).
Blunt and penetrating laryngeal or pharyngeal trauma can cause dysphonia, stridor, hemoptysis, hematemesis, dysphagia, neck emphysema, and dyspnea progressing to respiratory arrest.
Patients may present with signs of shock (diaphoresis, tachycardia, and hypotension) after experiencing significant blood loss.
Neurologic injury demonstrated by subjective complaints of pain and paresthesias, or more objective findings of hemiplegia, quadriplegia, and coma, may be observed.
Signs of esophageal injury include dysphagia and hematemesis.
Strangulation is a unique mechanism of blunt neck injury caused by hanging, ligature application, or manual neck compression.
The clinical presentation of strangulation depends upon the duration and amount of force applied to the neck. Cardiac arrest, cervical spine fractures, cerebral anoxia, arotid artery injuries, and hyoid bone and laryngeal fractures are possible. Increased venous pressure above the location of a ligature causes facial and conjunctival petechial hemorrhages.
TABLE 165-1 Signs and Symptoms of Neck Injury
DIAGNOSIS AND DIFFERENTIAL
The Roon and Christensen anatomic classification divides the neck into three zones (Table 165-2).
At-risk structures located in zone I are the proximal vertebral and carotid arteries, thoracic vessels, superior mediastinum, lungs, esophagus, trachea, thoracic duct, and spinal cord.
At-risk structures located in zone II are the mid-carotid and vertebral arteries, jugular veins, esophagus, trachea, larynx, and spinal cord.
At-risk structures located in zone III are the distal carotid and vertebral arteries, pharynx, and spinal cord.
Plain radiographs of the neck can identify the presence of penetrating foreign bodies, and a chest radiograph is warranted to assess for associated thoracic cavity injuries.
Helical CT angiography is the most commonly utilized diagnostic study for vascular injuries of the neck. It has a reported sensitivity of 90% to 100% and specificity of 98.6% to 100% for significant carotid and vertebral artery injuries, but is limited in detecting low zone I and high zone III injuries.
Proximal and distal surgical control of bleeding vessels is also more difficult in zones I and III, so conventional angiography may be preferred with injuries to these areas.
Blunt and penetrating esophageal injuries are often initially asymptomatic. Delayed diagnosis and treatment results in significant morbidity and mortality from deep space infections and mediastinitis.
CT is the initial diagnostic study to assess for esophageal injuries, but if this is nondiagnostic or suspicion of injury is high, esophagography and esophagoscopy should be performed. This combination of studies has a sensitivity of detecting injury that is nearly 100%.
Patients with any symptoms suggestive of laryngotra-cheal injury require laryngoscopy and bronchoscopy.
TABLE 165-2 Zones of the Neck
EMERGENCY DEPARTMENT CARE AND DISPOSITION
Initiate standard trauma protocols for evaluation and stabilization of trauma patients. Quickly establish high-flow oxygen, cardiac and respiratory monitoring, and IV access.
Immobilize and assess the cervical spine, as clinically appropriate.
Any patient with acute respiratory distress, expanding hematoma on the neck, massive subcutaneous emphysema, tracheal shift, impending respiratory arrest, or severe alteration in mental status requires the establishment of a definitive airway with endotracheal intubation or cricothyrotomy.
Evaluate the integrity of the larynx before intubation attempts as intubation of a fractured larynx may result in complete transection or creation of a false passage. Tracheostomy may be the best option for airway control in these patients.
Initiate volume resuscitation with crystalloid followed by blood products as needed.
Probing of neck wounds in the ED is never indicated; full exploration should occur in the operating room where the capacity for proximal and distal vascular control is optimal.
Direct pressure can often control active hemorrhage.
Blind clamping of blood vessels is contraindicated due to the complex vital anatomy compressed into a relatively small space and the danger of causing further injury with a misguided surgical instrument.
Injuries in proximity to the base of the neck predispose patients to simultaneous injury to the chest. Assess the chest for injuries such as pneumothorax and hemothorax.
Minor penetrating wounds that do not violate the platysma muscle require standard meticulous wound care and closure. Observe these patients for several hours in the ED. If asymptomatic and hemodynami-cally stable after 4 to 6 hours, these patients may be discharged home with close follow-up.
Wounds that violate the platysma muscle mandate surgical consultation. Admit these patients for surgical exploration or diagnostic evaluation for deep structure injury.
Patients with blunt neck trauma initially may present with subtle signs of injury and may develop significant symptoms on a delayed basis. After a period of observation, asymptomatic patients may be discharged with close follow-up, although a low threshold for admission should be maintained.
For further reading in Tintinalli’s Emergency Medicine: A Comprehensive Study Guide, 7th ed., see Chapter 257, “Trauma to the Neck,” by Bonny J. Baron.