Neck Trauma

Etiology

Three major mechanisms have been described in neck trauma:

1. Blunt trauma: This includes motor vehicle accidents and sports injuries. There may be delayed presentation of laryngeal, vascular, and digestive tract injuries if blunt trauma occurs. Also, beware that occult cervical spine injury may be present in patients with blunt neck trauma. In addition, a shoulder harness (seatbelt) may also be responsible for shearing trauma to the anterior neck.
2. Penetrating trauma: This comprises as much as 5% to 10% of all trauma injuries. Examples include gunshot wounds and stab wounds. It is the violation of the platysma that determines penetrating injury. Wounds that penetrate the platysma have the potential for severe injury. Consequently, it is wise to consider damage to the vital structures if the platysma is violated. Stab wounds involve low-energy penetration.
3. Near-hanging or strangulation: External neck pressure causes cerebral hypoxia due to venous and arterial obstruction. 

The most commonly injured area is zone 2, which can easily be accessed surgically. However, in zones 1 and 3 injuries, exposure and vascular control are more difficult to achieve.[4]

Epidemiology

The mortality rate for penetrating neck injuries is as high as 10%. The most common cause of death from penetrating neck trauma is a vascular injury. The area of highest risk is injuries at the base of the neck, in zone 1. The leading causes of delayed mortality are due to esophageal injuries, which may not be apparent on initial presentation.

Beware that up to 50% of gunshot wounds are accompanied by significant injuries. These carry a mortality rate of 10% to 15%.  Stab wounds cause serious injury in 20% to 30% of cases, with an overall mortality rate of 5%. The most common cause of delayed mortality is due to esophageal injury, which may not be readily apparent on initial presentation. [5][6]

Pathophysiology

The pathophysiology of neck injury depends on the mechanism of injury. The neck contains many critical organ systems adjacent to one another. It is for this reason that even innocuous-appearing wounds have the potential to cause either immediate or delayed life-threatening injuries or complications. It is rare to have a cervical injury without a neurological deficit in patients with penetrating neck trauma.[7]

With a low-risk National Emergency X-radiography Utilization Study I (NEXUS I) criteria, spinal cord injuries are unlikely to occur. These criteria obtain only if the patient is:

• Alert and awake
• Not intoxicated
• Has no signs or symptoms of neurologic injury
• Has no spinous process tenderness.

Zone 1 is a dangerous area and injuries in this region are potentially lethal. There is a potential for injury to the following important structures:

• Great vessels in the neck
• Mediastinum
• Cervical and thoracic esophagus

A high mortality rate accompanies zone 1 injuries. Vascular injuries are the most common of cervical injuries and occur in up to 40% of patients with penetrating neck trauma. A vascular injury should be suspected in the presence of the following hard signs. (Hard signs suggest the presence of a serious injury that needs immediate attention or intervention).

Signs suggestive of vascular injury:

• Rapidly expanding or pulsatile hematoma
• Severe hemorrhage or difficult to control bleeding
• Shock refractory to fluid resuscitation
• Decreased or absent pulse
• Vascular bruit or thrill
• Neurologic deficit (On physical examination, this is suggestive of cerebral ischemia)

Signs suggestive of esophageal injury:

• Massive hemoptysis
• Significant hematemesis
• Respiratory distress 

The soft signs of penetrating neck trauma include minor hemoptysis, hematemesis, dysphonia, dysphagia, subcutaneous, or mediastinal air, non-expanding hematoma. Beware that penetrating injuries involving zones 1 and 3 have a higher risk for occult vascular injury. Also, beware of the possibility of significant concurrent wounds in these zones to the head, chest, or abdomen. Suspect airway injury if dyspnea, hemoptysis, subcutaneous air, stridor, hoarseness, and dysphonia are present. Esophageal injuries may not be clinically apparent initially. In addition, beware that normal radiographs do not exclude esophageal injury.

History and Physical

The most important part of the evaluation is a careful and thorough physical examination. Obtain essential information about the mechanism of injury, is vital. This should include responses to the following considerations:

When: Timing of the injury

Where: Location of both the injury and number of wound sites (suspected entry and exit wounds), as well as their nearness to vital structures.

How: The type of wounding agent used, such as a knife, handgun, motor vehicle, etc.

Events surrounding the timing of the injury: This information can be obtained from the emergency management report and the law enforcement report.

Any other existing or underlying medical condition(s).

It is important to determine the extent of the injury and identify any associated injuries. Beware that are uncommonly isolated injuries, particularly in cases involving blunt trauma. Always attempt to identify any associated injuries.

Evaluate the neck for hemorrhage, hematoma, ecchymosis, edema, or any anatomic distortion. Auscultate for carotid bruits, stridor. Examine the neck for any tenderness or subcutaneous emphysema. The presence of certain findings provides clues for clinically significant vascular and aerodigestive injuries. Beware that signs and symptoms may be delayed. Bubbling or air emanating from a wound may suggest a tracheal injury. Crepitus may indicate that air has moved into the soft tissue space and should suggest prompt evaluation for injury to the trachea, esophagus, or pulmonary tree. A careful evaluation of the wound to determine the extent of the injury is required. Assess for penetration of the platysma. However, wounds should never be probed blindly, as this may cause uncontrolled bleeding. A full neurologic examination should also be performed.

Evaluation

Evaluation of neck injuries warrants notification of a trauma team or surgeon if either is available. Since physical examination may not be reliable in ruling out injuries in patients with neck trauma, one should consider a low threshold for obtaining additional imaging studies and/or surgical consultation. Periodic examination is required to identify deterioration in clinical status as well as any ongoing. The value of a thorough secondary survey to evaluate for additional injuries cannot be over-emphasized in such patients. Diagnostic testing is performed for stable patients manifesting soft signs of injury and, sometimes even for those who are asymptomatic at initial presentation. [8][9]

Chest Radiography

Obtain anterior and lateral neck and chest radiographs in any patient presenting with significant neck trauma and look for hemothorax, pneumothorax, or pneumomediastinum. These should be obtained especially for patients with zone 1.

CT Angiography

Angiography is the initial study to evaluate for vascular injury. This may provide information about injuries to additional structures and may delineate the path of the projectile. Since it is less invasive, it is more commonly used to define vascular neck injury.

Conventional Angiography

A four-vessel angiography with venous-phase imaging has a sensitivity of greater than 99%. This is the “gold standard” for evaluating vascular injury. If performed, should include the carotid and vertebral vessels, the intracranial portion of the carotid artery in zone 3 injuries, and the aortic arch with its branches in zone 1 injuries.

Duplex Ultrasonography

Duplex ultrasonography can be obtained in stable patients. It is non-invasive and relatively inexpensive, but it is operator-dependent.  In addition, non-occlusive injuries may be missed if the flow is preserved, such as with intimal flaps and pseudoaneurysms. Its role in zone III evaluation is also limited.

Esophagography 

Esophagography should be performed if an esophageal perforation is suspected.

Treatment / Management

Since the neck houses vital structures, prompt evaluation, and rapid intervention are required. The initial assessment should be performed according to the ATLS protocols. An immediate trauma service consultation should be obtained for patients with suspicion of vascular, tracheal, or esophageal injury.[10][11][12]

Priorities in the management of patients with neck trauma are like those for any other patient with a life-threatening condition.  The primary priorities are securing the airway, maintaining ventilation, controlling hemorrhage, and treating shock.  At the same time, check vital signs and determine the stability of the patient. Patients with neck injuries may have other life-threatening injuries that may take precedence.

Airway: As always, the priority is airway stabilization, particularly in patients with neck trauma, while maintaining cervical spine immobilization. Remember that in-line stabilization should always be maintained when there is a concern for a cervical spine injury. Up to 10% of patients with penetrating neck injuries may present with airway compromise. Be aware that despite a stable initial appearance, airway compromise can ensue rapidly.

Beware that swelling, distorted anatomy, and hematoma formation may contribute to impending airway obstruction in facial or neck trauma. Therefore, early airway control should be considered as the conditions may rapidly worsen.

Breathing: Evaluate the breathing and assess for any hemothorax or pneumothorax, particularly with penetrating zone 1 injuries

Circulation: Direct, simple pressure on the open wounds should be used to control bleeding in the emergency department. Wounds that have air sucking or bubbling should be covered with Vaseline gauze. No blind probing of the wound and no clamping of the vessels should occur in the emergency department. It is important not to occlude both carotid arteries or obstruct the patient's airway. Avoid nasogastric tube placement in patients with penetrating neck injury because of the risk of hematoma rupture. The agitation of the patient during tube insertion may precipitate bleeding.

Further management of the patient with penetrating neck trauma depends on the anatomic zone of injury, clinical presentation, and hemodynamic stability. Determine the zone of injury, as this will determine evaluation and management strategy.

Zone 1: Since up to one-third of patients with a clinically significant zone 1 injury may have no symptoms at their initial presentation, many centers advocate vascular evaluation of the aortic arch and great vessels, with an esophageal evaluation.

Zone 2: This area has easier surgical access and poses a low risk for adverse sequelae from exploration. The decision for surgical exploration depends on the symptoms.

Symptomatic penetrating zone 2 injuries should undergo neck exploration.

Asymptomatic patients with penetrating zone 2 injuries may be treated with either mandatory exploration or directed evaluation and serial examinations.

Indications for an angiogram: a stable patient with persistent hemorrhage or neurologic deficits. The presence of Horner syndrome (sympathetic nerve plexus injury) and hoarseness (recurrent laryngeal nerve injury). This suggests a violation of carotid sheath.

Zone 3

In this zone, there is potential for injury to major blood vessels and the cranial nerves close to the skull base. Beware that patients with arterial injuries may be asymptomatic at their initial presentation, and surgical exposure and control of bleeding in this location may be quite difficult.  In addition, many vascular injuries are amenable to definitive treatment by an interventional radiologist. Therefore, the injury can be potentially treated in the same setting as the one in which the diagnostic angiogram is done.

Bottom Line

1. Zones 1 and 3:  Difficult access, and exposure, vascular control may be challenging
2. No mandatory exploration, however, angiography is suggested.

For Unstable Patients

All unstable patients with evidence of vascular or aerodigestive injury should receive further evaluation by performing an invasive intervention. These patients should be transferred to the operating room for definitive care depending on the type and location of injury as well as associated injuries.

For Stable Patients

1. Whether to perform mandatory exploration of all zone 2 injuries
2. Whether to obtain invasive intervention in all zone 1 and 3 injuries

With improvements in multidetector (angiography, “mandatory” neck exploration for platysma violation, and “mandatory” arteriography for zones 1 and 3 injuries are falling out of favor. It is important that all patients with platysma muscle violation be admitted to the surgical service or the observation unit for ongoing observation, regardless of their stability.

Blunt Trauma

Up to 5% of traumatic injuries to the neck are due to blunt trauma. Motor vehicle accidents are the most frequent cause. It occurs when an unrestrained passenger may strike the neck on a dashboard or steering wheel.

Blunt trauma can damage the vessels by the following mechanisms

1. Direct damage
2. Excessive rotation and/or hyperextension: This causes stretching of the arteries and veins resulting in a shear injury.

It is often associated with other significant injuries. Beware that there are uncommonly isolated injuries, particularly in blunt trauma; therefore, always identify any associated injuries. 

Differential Diagnosis

• Injury to the spinal cord
• Strangulation

Complications

• Airway obstruction
• Aspiration
• Vocal cord paralysis
• Perforated esophagus
• Severe vascular injury
• Necrotizing infection
• Stroke
• Air embolism
• Pneumothorax, hemothorax