Penetrating Neck Injuries


Anatomy and Zones

  1. Anatomy
    2. Vascular Anatomy of the Neck
    Lateral Neck Anatomy Lateral Neck Anatomy


    Lateral Neck Anatomy
  2. Neck Zones

    3. Trauma Neck Zones of Injury
    1. Zone 1
      • extends from the clavicles to the cricoid cartilage
      • surgical exposure is difficult: sternum, ribs, clavicle
      • injuries have a high mortality rate from major vascular injury and intrathoracic injury
      • structures traversing zone 1 include the great vessels, proximal carotid artery, vertebral artery, lung, trachea, esophagus, spinal cord, major cervical nerve trunks

    2. Zone 2
      • extends from the cricoid cartilage to the angle of the mandible
      • surgical exposure is straightforward
      • structures traversing zone 2 include the internal jugular vein, common, external, and internal carotid arteries, vertebral artery, esophagus, trachea, larynx, hypopharynx, spinal cord

    3. Zone 3
      • extends from the angle of the mandible to the base of the skull
      • surgical exposure is difficult because of the mandible and skull base
      • structures traversing zone 3 include the jugular vein, distal internal carotid artery, vertebral artery, pharynx

  3. Tissue Planes
    1. Platysma Muscle
      • major anatomic landmark
      • management decisions are made depending on whether the injury has penetrated this layer

    2. Deep Cervical Fascia
      • supports and encircles the visceral and muscular structures of the neck
      • tough layer that provides a natural tamponade effect in case of vascular injuries
      • however, in a small closed space, this can result in extrinsic compression of the airway

Initial Management

  1. ABCDE
    • assessing and securing the airway is the top priority
    • significant external bleeding should be controlled with direct pressure: blind clamping of vessels is to be avoided
    • always consider the possibility of c-spine injury
    • chest x-ray to rule out pneumothorax
    • lateral c-spine x-ray to look for foreign bodies or subcutaneous air

  2. Clinical Evaluation of the Neck
    • physical findings are usually divided into hard and soft signs
    • management decisions are based on the zone of injury and the presence of hard or soft signs of injury

    Hard and Soft Signs of Neck Injury

Management of Unstable Patients

  1. Zone 1 Injuries
    • unstable patients belong in the operating room
    • choice of incision is based on what underlying vessel is injured
    • possible incisions are supraclavicular, median sternotomy, anterolateral thoracotomy
    • surgeon must be prepared to extend the initial incision or make additional incisions based on the operative findings
    • median sternotomy is used for exposure of the innominate, proximal right carotid and subclavian, and proximal left carotid arteries

    Possible incisions for penetrating Neck Trauma
    1. Proximal Left Subclavian Artery Injuries
      • proximal left subclavian artery is difficult to expose because it arises from the aortic arch posteriorly
      • a posterolateral thoracotomy provides excellent exposure but limits exposure to other vital structures
      • a ‘book’ thoracotomy provides the best exposure but is highly morbid: anterolateral thoracotomy, supraclavicular incision with resection of the medial clavicle, and a median sternotomy, which links the two horizontal incisions
      • a proximal occlusion catheter may be placed to control hemorrhage prior to definitive repair

    2. Mid to Distal Left Subclavian Artery Injuries
      • exposed by resecting the medial portion of the clavicle
      • the artery lies posterior to the vein
      • endovascular stent placement may be considered as definitive repair

  2. Zone 2 Injuries
    • anterior sternocleidomastoid incision for unilateral injury
    • transverse collar incision if both sides of the neck must be explored

    1. Internal Jugular Vein
      • venorrhaphy for simple injuries
      • patch venoplasty and segmental resection/primary anastomosis are also acceptable procedures in stable patients
      • extensive injuries or unstable patients should be managed with ligation
      • bilateral ligation should be avoided (increased intracerebral pressure, facial swelling)

    2. Carotid Artery
      • common carotid is more frequently injured than the external or internal carotid
      • common presentations include shock, expanding hematoma, brisk external bleeding, neurologic deficit, coma
      • ligation of the facial vein is required for adequate exposure
      • must avoid injury to the adjacent vagus and hypoglossal nerves
      • carotid artery repair is indicated in all patients except those with coma and no evidence of prograde flow
      • minor injuries can be repaired primarily
      • complex injuries will require an interposition graft with autogenous vein or PTFE
      • role of shunts remains controversial

    3. Vertebral Artery
      • injury is usually not detected unless arteriography has been performed
      • in a stable patient, expectant management is favored
      • ongoing bleeding, arteriovenous fistula, or pseudoaneurysm is best managed by angiographic embolization

    4. Esophagus
      • there is significant morbidity and mortality for either a missed or delayed diagnosis of an esophageal injury
      • NG tube facilitates identification and dissection
      • procedure of choice is debridement of devitalized tissues, primary repair, and wide drainage
      • if the injury is extensive or if the diagnosis has been delayed for more than 24 – 48 hours, then distal ligation and proximal esophagostomy is necessary

    5. Trachea
      • simple lacerations may be repaired with an absorbable monofilament suture
      • resection and end-to-end anastomosis can be performed for more extensive injuries as long as the anastomosis is tension-free
      • significant injuries will also require a tracheostomy, which may be placed above the level of the injury

    6. Combined Tracheoesophageal Injuries
      • each injury should be managed individually
      • to avoid postop fistulas, a muscle flap (sternocleidomastoid or strap muscle) should be interposed between the 2 suture lines

Management of Stable Patients

  1. Zone 1 Injuries
    • management is selective
    • CT angiography is performed to identify vascular injury
    • esophageal injury is excluded by esophagography and esophagoscopy
    • bronchoscopy is used to exclude injury to the trachea

  2. Zone 2 Injuries
    1. Mandatory Operative Intervention
      • historically, any zone 2 injury that penetrated the platysma required operative exploration
      • based on the experience in World War II, during which the mortality rate from penetrating neck injuries was decreased by ~50% after adopting a mandatory neck exploration policy
      • however, because of the high incidence of negative neck explorations, as well as better diagnostic tools, this policy has become less common in recent years
      • most people still recommend mandatory exploration for gunshot wounds

    2. Selective Management
      • if there is no clinical evidence for injury to a vital structure, then bronchoscopy/laryngoscopy, esophagoscopy/esophagography, and CT angiography are performed
      • operation is performed only if an injury is detected by one of these studies
      • since mortality rates do not appear to be less with this approach, it has become the most common way to handle zone 2 neck injuries

  3. Zone 3 Injuries
    • selective management is the rule because of the difficulty of operative exposure
    • CT angiography is performed to rule out injury to the distal internal carotid
    • most vascular injuries identified in zone 3 can be managed by endovascular stent placement
    • esophageal studies are not necessary







References

  1. Cameron, 11th ed., pgs 1081 – 1085
  2. Sabiston, 20th ed., pgs 423 – 424