Penetrating Injuries of the Neck

Neck wounds that extend deep to the platysma are considered penetrating injuries.

Frequency

Incidence of penetrating neck injury is closely related to incidence of violent crime and military conflict. In the United States, most penetrating neck injuries in the adult population are secondary to assault. Less frequently, some injuries to adults and most pediatric cases result from accidents involving a fall or motor vehicle accidents. However, the actual frequency of accidental penetrating neck trauma remains unreported.

In the United States, penetrating neck injuries contributed to less than 2% of all reported injuries in 2013. Despite the relative infrequency, severe neck injuries are associated with a high case fatality rate. ^[4]

Penetrating neck trauma is more frequent during military conflict. ^[5] Neck injuries accounted for as many as 17% of all injuries sustained by US troops in Iraq and Afghanistan. Most of these involved penetrating wounds and carried a mortality rate of up to 4%. ^[6]

The incidence of penetrating neck trauma in pediatric patients younger than age 15 years is extremely low (0.28%). Stab injuries (44%) far outnumber injuries due to gunshots (24%) in this age group. The overall mortality rate of 5.6% is linked to independent risk factors such as vascular injury and hypotension upon presentation to the emergency department. ^[7]

The most common causes of penetrating neck trauma are missile injuries from firearms and stab injuries. Blast injuries with penetrating bomb and mortar fragments are less common. Accidental penetrating injuries are most often due to falls on sharp objects such as sticks or glass. Motor vehicle accidents are another cause of accidental penetrating injuries.

Penetrating missile trauma can be a low-velocity injury or a high-velocity injury. ^[5] The wounding capacity of a missile is directly proportional to its velocity. Low-energy wounds caused by a projectile traveling at a velocity less than the speed of sound usually result in the laceration of soft tissue with comminution of bone and the missile itself. High-energy wounds are produced by missiles traveling faster than the speed of sound. Large amounts of energy are transferred to the tissues of the body and result in perforating or avulsion wounds to the soft tissue, with ablation of cortical bone. The high energy imparted to the tissues (and therefore the degree of damage from high-velocity missiles) is often underestimated.

Stab injuries usually result in lesser degrees of injury than missile wounds. The rate of explorations with negative findings associated with mandatory surgical exploration of all stab injuries of the neck is 10% higher than the rate of explorations with negative findings in missile injuries.

Accidental injuries may result in the penetration of the platysma by a foreign object such as those made of metal, glass, or wood. Such injuries usually do not result in extensive collateral tissue damage, but foreign bodies may remain in the neck.

Penetrating neck wounds can cause injury to one or more major organ systems of the neck, including the great vessels, larynx and trachea, ^[8] esophagus, and spinal column. Injuries to the vascular system occur in 25-56% of penetrating neck wounds, and injuries to the carotid and subclavian arteries are the most common cause of mortality. Approximately 20-30% of penetrating neck wounds result in laryngeal, tracheal, or esophageal injuries. In addition to the major structures, numerous smaller structures in the neck can be injured with penetrating trauma, which often results in significant morbidity.

The treatment of a patient with a penetrating neck injury should follow the advanced trauma life support (ATLS) guidelines established by the American College of Surgeons, which begins with a rapid assessment of the airway, breathing, and circulation. ^{[9, 10]} Airway management in a patient with penetrating injury to the neck can be challenging. Expanding hematoma, subcutaneous emphysema, hoarseness, stridor, respiratory distress, hemoptysis, and hemodynamic instability all suggest injury to the airway and/or vasculature.

The approach to airway management must be individualized in these situations. ^[11] A seemingly stable airway can be lost rapidly in a patient with penetrating neck trauma. With injury to the laryngotracheal complex, intubation can be attempted, but great care must be taken to recognize tracheal disruption, which can lead to intubation of a false passage. A marginal airway may be lost if intubation is not performed expertly. Significant trauma to the larynx or cricoid generally requires tracheotomy. Controlled tracheotomy with local anesthesia is always preferred to an emergency tracheotomy necessitated by unsuccessful intubation attempts.

Once the airway is stable, breathing and circulation are evaluated and managed in the standard manner, following the ATLS protocol. The secondary survey is conducted after the patient is initially stabilized, and any associated injuries are noted. A thorough history should be obtained; it should include details about the mechanism of injury such as the type of projectile, distance between the gun and the victim, caliber of weapon, and number of shots fired.

Physical examination of the patient should focus on the 3 major organ systems commonly involved in penetrating neck injury: airway, vascular system, and upper digestive tract.

• Evaluation of the airway is focused on the respiratory status of the patient, such as the respiratory rate and signs of airway distress, including dyspnea and stridor. Vocal quality should be noted, and the patient should be questioned about changes in the voice. The neck and upper chest should be palpated for subcutaneous emphysema, and the larynx and trachea should be palpated for tenderness and crepitus. Flexible laryngoscopy, CT imaging, and/or direct laryngoscopy and bronchoscopy may be necessary to fully evaluate suspected airway injuries.

• Injuries to the great vessels of the neck may be obvious on physical examination and may present as an exsanguinating wound or expanding hematoma. A significant vascular injury may be subtle, with findings such as an absent distal pulse, bruit, or isolated neurologic deficit. Suspected vascular injuries can be further evaluated with appropriate imaging modalities and exploration.

• Injuries to the esophagus and pharynx are difficult to diagnose and may be missed during the management of other immediately life-threatening injuries. Bleeding from the mouth, drooling, and subcutaneous emphysema are all suggestive of upper digestive tract injury. Careful examination of the oropharynx and hypopharynx should be performed at the bedside, if possible. A contrast-enhanced study of the esophagus and esophagoscopy should be performed if injury is suspected clinically.

All patients with suspected or confirmed injuries to the neck that extend deep to the platysma should be treated according to a protocol of either mandatory neck exploration or selective management, depending on local availability of resources and the philosophy of the surgeon. ^[12] If a surgeon who is experienced in the management of penetrating neck injuries is not available or if the facility is not equipped to treat a patient with this type of injury, the patient should be stabilized and transferred to an appropriate medical center.

Prehospital trauma management protocols have been evolving, and evidence suggests that cervical spine immobilization in patients with a penetrating neck injury and intact neurologic status may not be useful and may be detrimental to quick assessment, airway securement, and injury management. ^{[13, 12]}

Airway compromise, massive subcutaneous emphysema, bubbling air through the wound, active bleeding, expanding hematoma, neurologic deficits, and hematemesis suggest major vascular or aerodigestive tract injuries. Patients who present with these “hard signs” and those with hemodynamic instability should be transferred to the operating room after a secure airway has been established. ^[10]

Patients in stable condition should undergo a thorough evaluation of the vascular structures of the neck and the aerodigestive tract prior to surgical intervention.

The lateral neck is divided into 3 zones; this system is useful in the evaluation and treatment of penetrating neck injuries. ^[14]

• Zone 1 extends from the clavicle to the cricoid cartilage and includes the thoracic inlet. This region contains the major vascular structures of the subclavian artery and vein, jugular vein, and common carotid artery, as well as the esophagus, thyroid, and trachea.

• Zone 2 extends from the cricoid to the angle of the mandible and contains the common carotid artery, internal and external carotid arteries, jugular vein, larynx, hypopharynx, and cranial nerves X, XI, and XII.

• Zone 3 is a small but critical area extending from the angle of the mandible to the skull base. This region contains the internal and external carotid arteries, jugular vein, lateral pharynx, and cranial nerves VII, IX, X, XI, and XII.

Every patient with a history of trauma should be evaluated and treated according to the ATLS guidelines established by the American College of Surgeons. ^[9] Penetrating neck wounds that appear to be life threatening must be addressed immediately. A contraindication to immediate management of a non–life-threatening penetrating neck injury is a life-threatening injury in another body system that requires immediate attention. After stabilization of the patient's condition, the workup should proceed in a timely manner.