Neck Trauma
Introduction
Any injury to the neck requires prompt evaluation as it can be potentially life threatening. Neck injuries are classified as blunt or penetrating, the latter of which refers to penetration of an object through the platysma muscle. Neck injuries are additionally categorized by anatomic zones (Figure 1) that can help the provider with differential diagnosis, workup, and treatment.
Anatomy
The neck is divided into three anatomic zones that help delineate injured structures and the need for operative exploration (Figure 1).
Zone I consists of the thoracic outlet structures located inferior to the clavicles and manubrium, extending cranially to the cricoid cartilage. Structures here include the trachea, esophagus, brachial plexus, lung apex, thoracic duct, and branches of the great vessels (the subclavian, vertebral, common carotid, internal carotid, external carotid arteries and the subclavian, internal jugular, and external jugular veins).
Zone II extends from the cricoid cartilage to the angle of the mandible, containing the distal carotid and vertebral arteries, jugular veins, vagus nerves and their branches, and the trachea and esophagus.
Zone III spans the area of the neck from the angle of the mandible to the base of the skull. It contains the pharynx, distal carotid and vertebral arteries, and distal jugular veins. Given its location, operative exposure is quite difficult to obtain to control injury.
The most common area of injury mandating operation is zone II, given its exposure and lack of protection, but is also the easiest zone to gain operative exposure and control.
Clinical Presentation
Specific injury patterns that mandate immediate operative intervention without further workup, termed “hard signs”, include pulsatile or expanding hematoma, active hemorrhage, hypotension and hemodynamic instability unresponsive to resuscitation, neurological deficits, significant subcutaneous emphysema, air bubbling from a neck wound, and airway compromise (Table 1).
Those patients with penetrating neck injuries in zone II that violate the platysma without “hard” signs, or those with any mechanism and “soft” injury signs (Table 1) mandate further workup to rule out injuries that may require operative intervention. Furthermore, some patients may initially present as asymptomatic which warrants careful observation dependent on the severity of the mechanism.
Table 1. Hard and Soft Signs of Injury to the Neck
| Structure | Hard Sign | Soft Sign |
|---|---|---|
| Vascular | ● Pulsatile hematoma ● Expanding hematoma ● Active hemorrhage ● Hemodynamic instability ● Neurologic deficit | ● Bruit or thrill ● Weak pulse ● Non-expanding hematoma ● Penetration through the platysma without hard signs |
| Airway | ● Respiratory distress ● Air bubbles in wound ● Massive subcutaneous emphysema ● Massive hemoptysis | ● Tenderness ● Dyspnea ● Mild hemoptysis ● Hoarseness/dysphonia |
| Digestive | ● Air bubbles in wound ● Massive subcutaneous emphysema ● Massive hematemesis ● Sepsis | ● Pain ● Dysphagia ● Mild hematemesis |
Evaluation
The first step in evaluation of a patient with trauma to the neck begins with the “ABCDs” of the primary survey (A=Airway, B=Breathing, C=Circulation, D=Disability), with special attention to the airway given its location within the central neck. Signs of overt respiratory distress should prompt rapid oral-tracheal intubation, which if unsuccessful or improbable necessitates a surgical airway. Following airway stabilization and completion of the primary survey, the physical exam should be focused on signs of vascular injury as well as aerodigestive injury (Table 1).
Plain radiographs of the chest and cervical region are useful rapid adjuncts that can rule out injuries that may require rapid intervention in the trauma bay (i.e. pneumothorax, hemothorax, tracheal deviation). The cervical spine should be immobilized with a collar, or heavy structures on each side of the neck to prevent lateral movement if no collar is available. Awake, alert patients without posterior midline neck pain on exam are unlikely to have cervical spinal injury and do not require further imaging, however those with any signs of pain or neurological deficit require immediate immobilization and further workup with plain films (anterior and lateral chest radiographs) or computed tomography (CT) imaging.
The previous dogma stating that any penetrating injury to Zone II that violates the platysma mandates immediate operative intervention is no longer valid given the high incidence of negative exploration. CT with the addition of angiography (CTA) is the preferred initial method to identify vascular injuries of the neck and screen for possible aerodigestive injuries, although is limited in cases where metallic shrapnel or bullet wounds are present due to streak artifact. In such cases, conventional angiography would identify vascular injuries.
If neither are available, duplex ultrasonography facilitates rapid bedside evaluation but is user dependent. Esophageal injuries should be ruled out with barium esophagography, as it has greater sensitivity than gastrografin in diagnosing injury, and/or esophagoscopy. Any suspicion for laryngotracheal injury warrants evaluation with bronchoscopy and laryngoscopy.
Management
Operative management for blunt and penetrating trauma to the neck depends on “hard” signs of injury, or if additional workup has been obtained identifying significant injuries. The first step is to ensure airway control. Any signs of airway compromise mandate prompt intubation, which if unsuccessful necessitates emergent cricothyroidotomy or tracheostomy. Hard signs of vascular injury (table 1) should be managed with direct pressure or foley balloon placement to tapenade the bleeding along with blood transfusion while transporting the patient directly to the operating room.
In the operating room, the patient should be placed supine and prepped widely from above the mandible all the way to the feet. Many vascular injuries to the neck may require vein harvesting for a conduit, and the saphenous vein is the most suitable candidate.
Operative exposure is dependent on the zone of injury: Zone I exposure is traditionally achieved via sternotomy, Zone II via linear incision along the sternocleidomastoid (SCM) or collar incision if there is concern for bilateral injury, and Zone III with extension of the traditional SCM incision, occasionally requiring dislocation of the mandible (Figure 2).
In Zone I injuries, significant penetrating or blunt trauma mandates a midline sternotomy to achieve proximal vascular and airway control within the mediastinum. Occasionally, the incision must be extended horizontally with a supraclavicular incision and anterolateral thoracotomy to create an “open book” thoracotomy (Figure 2), which allows for access to the heart, subclavian artery and branches of the aorta and superior vena cava.
Subclavian artery injuries are best approached with a cervicothoracic incision when the patient is unstable, and left subclavian artery injury may mandate resection of the clavicle or trap door incision. If the patient is stable and endovascular options are available, arteriography and endovascular stent placement can avoid the morbidity of operative intervention. The subclavian artery can be ligated without significant morbidity, but debridement and primary repair should be performed if possible. Injuries to the proximal esophagus and trachea are best approached through a right thoracotomy.
In Zone II injuries, patients are positioned by placing a bump under the shoulders to extend the neck and rotating it to the side contralateral to the area of injury. A vertical incision is created along the anterior border of the SCM muscle, carrying the dissection through the skin, subcutaneous tissue, and platysma. In the event of bilateral injury, the standard neck incision can be substituted with a collar incision 2 fingerbreadths above the sternal notch for better exposure. Once through the subcutaneous tissue and platysma, the SCM is retracted laterally. If the exact injury is unknown, the vascular structures within the carotid sheath (internal jugular vein, carotid artery) are explored first.
The carotid artery is best identified after entering the carotid sheath and dividing the middle thyroid vein as well as the facial vein as it enters the internal jugular vein. The carotid artery is located medially and posterior to the internal jugular vein and can be better visualized by retracting the internal jugular vein laterally. The vagus and hypoglossal nerves are in close proximity to the carotid artery and so should be carefully avoided. If the jugular vein is injured, it can be repaired with 6-0 prolene or ligated if repair is not possible. For arterial bleeding, proximal and distal control of the carotid artery must be obtained prior to repair. Given the high risk of cerebral ischemia, any injury to the common and internal carotid artery should be repaired.
If exposure proves difficult due to extension into Zone I or Zone III, control can also be obtained by passing a Fogarty balloon into the artery. Before clamping or excluding the artery, the patient should be systemically heparinized unless contraindicated (i.e. intracranial hemorrhage).
Devitalized edges of the artery should be debrided sharply. In general, sharp penetrating injuries can be repaired primarily using 6-0 prolene via simple closure for short segment injuries or end-to-end anastomosis for complete transections. Large defects that are not amenable to primary repair may require resection of the affected segment and an interposition graft, preferably with a saphenous vein. Injury near the carotid bifurcation should be repaired with a patch angioplasty to prevent stenosis. The external carotid can be ligated with minimal sequelae, however the common and internal should always be repaired.
In the worst-case scenario, temporary carotid artery shunting can be achieved by placing intravenous tubing into the artery and tying each end of the artery over the tubing. This can allow for transportation to a higher level of care when resources are limited. Vertebral artery injuries should be repaired when possible, although can be ligated or temporarily controlled with bone wax at the base of the skull while angiographic intervention is prepared for the difficult regions such as extension into Zone III.
Once vascular injury has been controlled, attention is then turned to exposure of the esophagus and trachea. The omohyoid is usually divided to access the esophagus. The esophagus is mobilized by dissecting through the areolar plane between the esophagus and cervical spine.
Nasogastric tube placement can help identify the esophagus, which should be encircled with a penrose and taking great care to avoid injury to the recurrent laryngeal nerve within the tracheoesophageal groove. Full thickness injuries to the esophagus should be debrided to healthy tissue and repaired primarily in two layers: a 4-0 absorbable interrupted suture for the mucosal layer and 3-0 running or interrupted suture for the muscularis. A muscle flap with the SCM or omohyoid should be mobilized and buttressed to the suture line, especially if there is concurrent tracheal injury to avoid tracheoesophageal fistula.
For gross contamination, the area should be widely drained. Injuries that are not amenable to repair may require esophageal exclusion and gastrostomy or jejunostomy. Intraoperative esophagoscopy can assist in identifying injuries by submerging the field in saline and examining for bubbles. Any patient with a repaired esophageal injury should have a barium swallow study on postoperative day 5 before starting oral intake.
Tracheal injuries can occur with blunt or penetrating injuries. Small injuries can be repaired in a single layer with 3-0 absorbable interrupted sutures, also taking care to buttress the suture line with vascularized muscle. Larger injuries may require resection of the defect and anastomosis. If a tracheostomy is required due to severe crush injuries or injuries >⅓ of the circumference of the trachea, it should be placed a ring distally to the injury. Bronchoscopy is another useful adjunct to evaluate for injury during operative exploration of the neck.
Zone III injuries are very difficult to gain exposure. For Zone III, the standard Zone II neck incision is extended cranially to the angle of the mandible. For distal vascular injuries, exposure may require disarticulation or partial resection of the mandible. Rarely, a partial craniotomy may be required. If exposure and control of hemorrhage cannot be obtained through these methods, endovascular treatments with stenting or embolization should be pursued. Vascular and aerodigestive injuries should be repaired as discussed previously in Zone II.
Postoperative management
Patients will most likely require hemodynamic, neurologic, and respiratory management and monitoring in the postoperative period which should take place in the intensive care unit if one is available. With vascular injury, transfusion with whole blood or 1:1:1 (1 unit of packed red blood cells, 1 unit of platelets, and 1 unit of fresh frozen plasma) should occur in the preoperative and intraoperative period, and may be required to catch up in the postoperative period.
With vascular injury that has been repaired, anticoagulation is paramount to prevent thrombosis if there are no contraindications such as intracranial hemorrhage or intraabdominal hemorrhage. Barium esophagram should be performed between postoperative days 5 and 7 to assess for esophageal leak after repair, or on postoperative day 1 if no esophageal injury was identified intraop prior to initiating a diet.
Complications
- Complications can arise from untreated traumatic injuries as well as sequelae from operative intervention.
- Untreated tracheal and esophageal injuries can result in stenosis, obstruction, sepsis, mediastinitis, esophageal leak and tracheoesophageal fistula.
- Venous and arterial injuries can result in death from massive hemorrhage and airway obstruction.
- Carotid artery injuries, including thrombosis from blunt trauma, and carotid artery ligation in the face of severe hemorrhage, can result in devastating cerebral ischemia and stroke.
- Patch, primary, and conduit repairs of the carotid artery can blow out, resulting in massive exsanguination.
- Vertebral arteries, carotid arteries, and jugular vein injuries can be complicated by thrombosis which is managed with antiplatelet therapy.
- Cervical spinal trauma can result in paralysis or death, which is why cervical spinal stabilization is paramount.
- Vagus or recurrent laryngeal nerve injury during operative exploration can result in hoarseness of the voice, or if bilateral can cause vocal cord paralysis and necessitate tracheostomy.
Summary
Penetrating and blunt injuries to the neck are grouped into three zones with different operative exposures. In zone I, a vascular injury can result in massive hemorrhage into the chest and mediastinum, necessitating a median sternotomy to gain exposure and control.
Zone II vascular injuries can cause significant airway compression, so prompt management of the airway with endotracheal intubation or surgical airway is paramount.
Zone III injuries are the most difficult to control given their location towards the base of the skull, and vascular injuries are best controlled temporarily with compression or balloon tamponade followed by endovascular options.
Hard signs of vascular and aerodigestive injury mandate operative exploration, whereas soft signs require further diagnostic workup with CT arteriography, duplex ultrasound, esophagoscopy, barium swallow, and bronchoscopy. Any concern for cervical vertebral body injury mandates prompt neck immobilization and further workup with CT cervical spine and neck CT arteriography.
References
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