Anatomy and classification of neck zones . Reprinted from Ryan’s Ballistic Trauma, Neck injury, 2011, 395–418, Matthew J. Borkon, Bryan A. Cotton, with permission of Springer
Neck zones in relation to the great vessels and neck vessels . Reprinted from Van Waes OJ, Cheriex KCAL, Navsaria PH, van Riet PA, Nicol AJ, Vermeulen J. Management of penetrating neck injuries. British Journal of Surgery 2011 Dec; 99 (S1): 149–154. Copyright © 2011 British Journal of Surgery Society Ltd. Published by John Wiley & Sons, Ltd.
Zone 1: Starts from the sternal notch to the cricoid cartilage
Zone 2: Starts at the cricoid cartilage and extends to the angle of the mandible (Fig. 4.3)
Direct bullet entry to neck zone 2
Zone 3: Represents the area of the neck that extends cephalad above the angle of the mandible (Fig. 4.4)
Victim of a knife blade-penetrating stab wound to neck zone 3
Zone 2 is the most exposed part of the neck and is relatively easily accessible. On the other hand, zones 1 and 3 are fairly inaccessible, as access to zone 1 is limited by the clavicle and the sternum, and access to zone 3 is constrained by the neck structures and the base of the skull  (Fig. 4.5).
Scout sagittal CT brain showing knife blade-penetrating stab wound to neck zone 3
In conflict areas, patients with penetrating neck injury may present acutely to the emergency department or to an advanced medical center after having received initial care at a local or battlefield hospital. The care of all patients initially should follow the ABCs of trauma care : securing the airway, and maintaining breathing and circulation. The importance of circulation and controlling exsanguinating hemorrhage has been recently stressed as a vital principle in the management of penetrating neck injuries  (Fig. 4.6). Neck stabilization with a C collar, however, has proven to be superfluous in battlefield penetrating injuries as the incidence of spinal column instability following such penetrating injury is very rare. In addition, a neck collar may mask a serious penetrating injury and may expose the paramedic personnel to unnecessary harm while trying to insert it on the field .
Length of a knife blade-penetrating stab wound to neck zone 3
Due to the straightforwardness of the accessibility of zone 2, neck injuries that violate the platysma in that zone were traditionally treated with routine exploration. However, for injuries in zones 1 and 3, the treatment was a selective management based on evaluation of all the structures present in these areas  (Fig. 4.7). The high rates of negative neck exploration for zone 2 neck injury and the limitations of scarce resource availability when having multiple patients with penetrating injuries further led to the evaluation of selective management for zone 2 injuries . Furthermore, in patients with bilateral zone 2 neck injuries, neck injuries that traverse the midline, and those with shotgun injury, a selective management may avoid bilateral neck exploration providing a customized treatment. Such customization will clarify if an exploration is needed and may guide the selected incision and approach especially for zone 1 injury .
Zone 3 neck bullet injury with angiogram showing a shrapnel next to the carotid artery with no arterial injury
Clearly, the management also largely depends on the stability of the patient and the presence of hard signs of vascular injury . The hard signs include active bleeding, absent distal pulses, expanding hematoma, bruits, thrill, and subcutaneous emphysema. A gauze (4 × 4) dressing is applied with local gentle compression on the injury site to control mild to moderate bleeding. Massive arterial bleeding is best initially controlled by inserting a Foley catheter in the hole of the penetrating wound and inflating the balloon to tamponade the bleeding [15, 16].
Zone 1 stable patients: In a zone 1 stable patient, the surgeon needs to rule out the presence of arterial, tracheobronchial, or esophageal injuries . As such, a selective angiography or CT angiography is first performed to rule out vascular injury. A trachea-bronchoscopy is performed to rule out injury to the tracheobronchial tree, and an esophagoscopy or a contrast swallow is performed to rule out gastrointestinal tract injuries. It is very vital to identify injuries to the GI tract as they could lead to mediastinitis which, left untreated, will have a very poor outcome. The longer the delay the worse is the outcome of a missed esophageal injury.
The selective angiography or CT angiography will determine the presence of injury to vessels of the thoracic inlet  (Fig. 4.8). Clearly, that area is very congested with structures starting from the aortic arch to the major vessels, specifically, the innominate artery and vein, left common carotid, and left subclavian arteries and veins. The injury site will help determine which surgical approach is going to be necessary. A median sternotomy typically offers exposure to all the vessels of the thoracic inlet except the left subclavian artery which may be very challenging to secure from a median sternotomy. An injury to the left subclavian artery typically requires a left anterior thoracotomy for exposure and management. Some injuries may be amenable to endovascular therapy by inserting a covered stent that seals the injured artery. Such management requires the presence of an experienced team and the availability of an appropriate inventory of stent graft material. There is always concern about the use of foreign body and grafts in such contaminated wounds . However, when possible, an endovascular approach may be very desirable despite the risk of late graft infection as it avoids the need for a sternotomy or a complex thoracotomy in a multiply injured patient.
Angiogram showing pellets around the carotid artery
Zone 1 unstable patients: In zone 1 unstable patients especially if in extremis, these individuals are best managed by immediate exploration in the operating room via emergent sternotomy which allows prompt and full exposure to all the vessels except the left subclavian artery. Typically the incision of the median sternotomy can be extended to the right or left neck to allow exposure of the right or left common carotid arteries and veins. It can be extended towards the right supraclavicular region to allow for full exposure of the right subclavian artery. If the injury appears to be originating from the left subclavian artery, an experienced thoracic or trauma surgeon may be able to get control of the origin of the left subclavian through an existing median sternotomy. This is extended to a left supraclavicular incision for further distal control. If this extension does not offer the needed exposure, a left third anterior thoracotomy will be needed converting the incision into a chest trapdoor incision. Such exposure will provide full exposure of the left subclavian artery at the cost of significant morbidity.
Zone 2 stable patients: In zone 2 stable patients and due to the direct accessibility of the structures in that area, the management remains variable and depends on the local facility and resources available . Patients with obvious hard signs and symptoms of vascular, tracheal, or esophageal injury are taken directly to the operating room for neck exploration. Patients who are asymptomatic can be treated by either mandatory or selective exploration. Immediate exploration allows prompt evaluation and management of the injured neck structures. This, however, requires general anesthesia, a neck incision, and availability of an operating room and its team, which may not be immediately available due to the presence of multiple other injured patients.
With selective exploration, a carotid angiography or CAT scan angiography is performed first followed by a dilute barium or gastrografin swallow with possible bronchoscopy . The disadvantage of the selective management is that arteriography can have false-negative rates and may miss venous injury . The barium swallow is not very sensitive and missed esophageal injuries have very high morbidity and mortality compared to a negative neck exploration which typically has minimal mortality and morbidity and may be less costly than a pan-endoscopy and a digital subtraction angiography. Surgeons in favor of selective management would argue that the rate of negative routine exploration is very high if done for any penetration of the platysma. They will claim that the delay in repair that may occur due to investigation with pan-endoscopy and angiography is unlikely to cause an increase in morbidity. In addition, an intimal fracture that may be missed by routine neck exploration can be identified by angiography.
Furthermore, not uncommonly, patients with zone 2 injury have a coexisting zone 1 injury which will require investigation with angiography and upper GI study. Similarly, if the injury extends posteriorly and there is concern regarding a possible vertebral artery injury, an angiography will also be needed.
Clearly the management can be individualized to fit the patient’s presentation and the local resources. In cases of mass casualty or multiple injured patients , wheeling every patient with a penetrating neck injury to the operating room may not be possible and may be very taxing to the available resources. In civilian penetrating neck injuries, Frykberg et al. evaluated the role of physical examination and clinical experience in the management of zone 2 neck injury and showed it to be very reliable. In a study of 124 patients, 30 had hard signs and were taken directly to the operating room to find that 28 had significant vascular injury, with a falsely positive rate of 6.7%. Twenty-three had no hard signs, but due to the involvement of other zones had an angiogram which identified three injuries, with only one needing intervention. The remaining 91 patients had no hard signs and were observed for 24 h. In these patients, no complications were noted nor was delayed surgery needed. The missed injury rate was 0.74%. As such, Frykberg et al. concluded that physical examination alone for zone 2 neck injury is safe and accurate in their hands. Such an approach may be applicable to conflict injuries and may be useful in centers with limited resources or until patient evacuation and transfer to a more advanced center are completed. The physical exam can also be supplemented with duplex ultrasonography if available. Frykberg et al. evaluated the value of duplex scanning versus arteriography for cervical vascular injury and showed that both modalities are of comparable accuracy.