Neck level algorithmic approach to trauma

Owing to complex anatomy, the neck has classically been divided into 3 zones extending from caudal to cranial, with additional anterior and lateral divisions (Figure 1). Zone 1 is the most caudal zone and extends from the level of the sternal notch/clavicles to the cricoid cartilage. Zone II continues from the cricoid cartilage to the angle of the mandible. Zone III includes the angle of the mandible to the base of the skull. Additionally, the posterior border of the sternocleidomastoid muscle divides the neck into anterior and posterior sections. Table 1 depicts the zones of the neck and the various structures found within each zone. Figure 2 depicts a view of deep dissection of the neck, revealing the complex neurovascular anatomy.

The initial evaluation of neck trauma should follow Advanced Trauma Life Support guidelines. This includes identification of life-threatening injuries during the primary survey such as airway obstruction from adjacent hematoma, laryngotracheal laceration, active bleeding, and tension pneumothorax. A difficult airway may require a cricothyrotomy, active hemorrhage may require manual pressure and/or balloon tamponade, and tension pneumothorax may require tube thoracostomy. Massive transfusion protocol can be initiated as needed early during resuscitation. Once such life-threatening issues have been managed in the primary survey, a secondary survey is performed to identify occult neurovascular and aerodigestive injuries. Of note, due to low incidence of unstable spine fractures in penetrating neck injury, cervical spine mobilization is not routinely recommended as it may prevent a thorough exam. The initial management priorities for both blunt and penetrating neck trauma are similar, though injury patterns may differ and are discussed below.

After exclusion of cervical spinal injuries, trauma to the remaining structures in the neck is uncommon. Laryngotracheal and pharyngoesophageal injuries, which usually occur in the setting of a direct blow to the neck, are rare. However, blunt cerebrovascular injuries (BCVIs), including carotid and vertebral artery injuries, can account for up to 3% of blunt neck trauma. Several patterns of injury predict high risk for BCVIs, including: near-hanging with cerebral anoxia; seatbelt sign of the anterior neck; basilar skull fracture involving the carotid canal; severe cervical hyperflexion/rotation/hyperextension; cervical vertebral body fracture or distraction; focal neurological deficits; displaced facial fractures; hard signs of vascular injury.^, A high index of suspicion should warrant CT angiography of the neck, which is the test of choice for initial screening and has replaced the more invasive conventional angiography. Table 2 lists the R Adams Cowley Shock Trauma grading scale for BCVIs. Management options for BCVI include anticoagulation and/or antiplatelet therapies, endovascular intervention, or a combination of both. A management algorithm for BCVIs is shown in Figure 3. Blunt laryngotracheal and pharyngoesophageal injuries are rare, but a delay in diagnosis may result in relatively high morbidity and mortality. Diagnosis of such injuries is similar to that by penetrating mechanism and is discussed below. For evaluation of cervical spinal injuries, spine surgery consultation is recommended.

Historically, injury to Zone II of the neck mandated operative exploration. Injury to zones I or III were typically worked up with angiography and triple endoscopy (laryngoscopy, bronchoscopy, esophagoscopy), a labor-intensive process. Over the past 2 decades, mandatory zone II exploration has been shown to have a high negative exploration rate (reference). Coupled with the advancement of high-quality computed tomography (CT) imaging and poor correlation between external injury and extent of internal injury, the evaluation and management of penetrating neck trauma has now evolved to a modified approach with a greater use of diagnostic imaging followed by selective operative management (). Therefore, the decision to take a penetrating neck injury patient to the operating room employs a modified “no-zone” based approach, which relies on the physiological status of the patient as well as physical exam findings. A detailed physical exam is noted to be >95% sensitive for detection of arterial vascular injuries, but less so for aerodigestive injuries. Presence of hard signs of injury (Table 3) regardless of zone, should mandate prompt surgical exploration.

For the majority of other patients who are initially stable and do not require urgent operative exploration, further workup is warranted. Diagnostic tools involve chest X-ray, computed tomography (CT) angiography, conventional angiography, and esophageal and laryngotracheal studies.

A plain film of the chest should be obtained in all Zone 1 injuries, as there is up to 15% incidence of hemo- and/or pneumothorax. Conventional angiography for diagnosis of vascular neck injuries was for many years the gold standard. However, studies have shown that in asymptomatic patients, routine angiography appears to be low yield, as occult injuries diagnosed via angiography tend to be benign and seldom warrant intervention (C). Instead, multidetector CT angiography has now been recognized to have a high sensitivity and specificity (>90%, 100% respectively) for detection of vascular neck injuries and allows for evaluation of wound tract trajectory (reference). For patients who may require endovascular management of zone I and III injuries, CTA provides a high quality preoperative road map. One downside to CT imaging is its poor sensitivity for detection of pharyngo-esophageal injuries. Such injuries are notoriously difficult to diagnose on physical exam and, if missed, have devastating consequences with high morbidity and mortality. Therefore, for nonintubated, hemodynamically stable patients, the study of choice is contrast esophagram with water soluble contrast (Gastrograffin) and if no leak identified, with thin barium. Esophagography has high sensitivity and specificity for identification of perforations. If intubated or the patient's mental status does not allow such a study, a flexible or rigid endoscopy may be performed (C). If there is concern for laryngotracheal injury (hoarseness, subcutaneous emphysema, minor hemoptysis), flexible fiber-optic endoscopy can be performed.

An algorithm for the assessment of penetrating neck trauma is shown in Figure 4. This algorithm is based on the Western Trauma Association's recommended guidelines and utilizes a modification to the traditional zone based approach. There is emphasis on early operative intervention in patients who present with hard signs of injury after neck trauma, with an alternative algorithm based approach in those who are hemodynamically stable and require further workup.