Chapter 3 – Neck Injury




Abstract




Neck injuries, particularly those due to penetrating trauma, are difficult to evaluate and manage due to the dense concentration of vital structures in a small anatomical space that can be surgically challenging to access. Only 15–20% of patients with penetrating trauma and very few with blunt mechanism require operative intervention. Meticulous clinical examination and well-selected diagnostic investigations are paramount to safely selecting those patients who require an operation and those that can be observed.





Chapter 3 Neck Injury


Demetrios Demetriades and Lydia Lam



Introduction


Neck injuries, particularly those due to penetrating trauma, are difficult to evaluate and manage due to the dense concentration of vital structures in a small anatomical space that can be surgically challenging to access. Only 15–20% of patients with penetrating trauma and very few with blunt mechanism require operative intervention. Meticulous clinical examination and well-selected diagnostic investigations are paramount to safely selecting those patients who require an operation and those that can be observed.


During the primary survey, the following life-threatening conditions in the neck should be identified and treated:




  1. 1. Airway obstruction due to laryngotracheal trauma or compression by external hematoma



  2. 2. Tension pneumothorax, especially in patients with penetrating trauma in the supraclavicular area



  3. 3. Severe active bleeding, externally or into the thoracic cavity



  4. 4. Spinal cord injury



  5. 5. Ischemic brain damage due to carotid artery occlusion


During the secondary survey, the following neck pathologies should be identified and managed:




  1. 1. Occult vascular injuries



  2. 2. Occult laryngotracheal injuries



  3. 3. Occult pharyngoesophageal injuries



  4. 4. Cranial or peripheral nerve injuries



  5. 5. Small hemopneumothoraces



Clinical Examination


Clinical examination according to a carefully written protocol is the cornerstone of the neck trauma diagnosis and management. The examination should be systematic and evaluate the vessels, the aerodigestive tract, the spinal cord, the nerves, and the lungs:




  1. 1. Vascular structures: “Hard” signs and symptoms highly diagnostic of vascular trauma include active bleeding, shock not explained by other injuries, expanding or pulsatile hematoma, absent or significantly diminished peripheral pulses, and bruit. “Soft” signs and symptoms suggestive but not diagnostic of vascular trauma include mild shock, stable hematoma, and slow bleeding. Only about 2% of patients with soft signs have significant vascular injuries requiring intervention. The presence of a seat-belt mark in the neck is a suspicious sign of associated vascular trauma. Unexplained neurological findings (coma, hemiplegia) may be due to a vascular injury. This group of patients requires CTA to evaluate the neck vessels.



  2. 2. Aerodigestive tract: Hard signs or symptoms highly diagnostic of significant laryngotracheal trauma include respiratory distress, air bubbling through a neck wound, and massive hemoptysis. There are no hard signs diagnostic of esophageal trauma. Soft signs and symptoms suspicious of aerodigestive trauma include subcutaneous emphysema, hoarseness, odynophagia, and minor hemoptysis. Only about 15% of these patients have significant aerodigestive injuries.



  3. 3. Nervous system: The examination should include GCS, localizing signs, pupils, cranial nerves (VII, IX–XII), spinal cord, brachial plexus (median, ulnar, radial, axillary, musculocutaneous nerves), the phrenic nerve, and the sympathetic chain (Horner’s syndrome). Many patients with neck trauma have associated head injuries and abnormal neurological examination; therefore, a meticulous examination is necessary to account for all potential injuries. Also, in injuries to the carotid or vertebral arteries, the patient may present with neurological signs, such as low GCS or hemiplegia.



Investigations in Neck Trauma


Unstable patients with hard signs of major vascular or laryngotracheal injuries should forgo further investigation and be taken directly to the operating room. CT scan and angiographic investigations should be considered only in stable patients. Selected patients with hard signs of vascular trauma that are stable or respond to initial resuscitation may benefit from CTA or formal angiography to determine if the lesion is a candidate for stenting or embolization, if this capability is readily available at the institution.




  1. 1. Plain chest and neck films can diagnose foreign body, fracture, pneumothorax, subcutaneous emphysema, and, in some cases, hematoma.



  2. 2. CT scan of the neck is the most valuable investigation in both blunt and penetrating trauma.



  3. 3. CTA is the investigation of choice in suspected vascular injury. In addition, after GSW, it can reliably identify a bullet tract, allowing the provider to have a more specific understanding of the potentially injured structures and thus narrow the need for additional investigations.



  4. 4. Diagnostic catheter angiography should be reserved only for cases with shotgun injuries and multiple pellets, or when the CTA is not conclusive. However, it has a definitive therapeutic role for embolization of a bleeding vessel or endovascular stenting of an injured vessel, false aneurysm, or an arteriovenous fistula.



  5. 5. Color flow doppler is noninvasive, accurate, and cost-effective. In addition, it does not require additional intravenous contrast if the patient has already received contrast for other investigations. The combination of a good physical examination and color flow doppler can detect or highly suspect most vascular injuries, including minor ones. Limitations include visualization of the proximal left subclavian artery in obese patients, the internal carotid artery near the base of the skull, and parts of the vertebral artery under the bony part of the vertebral canal.



  6. 6. Esophagogram should be considered in patients sustaining penetrating trauma with subcutaneous emphysema, odynophagia, or hematemesis, especially if the CT shows a wound tract near the esophagus. Very often it is supplemented by esophagoscopy. The sensitivity of the esophagogram is best for evaluation of the thoracic esophagus and less well suited for the high cervical esophagus.



  7. 7. Esophagoscopy and laryngoscopy/tracheoscopy are indicated in patients with suspicious findings, such as subcutaneous emphysema, or a wound tract near the esophagus or trachea.



General Management


In an urban environment, the “scoop and run” principle should be applied in penetrating neck injuries. Any external bleeding should be controlled by direct pressure. Protective cervical spine collars should be applied loosely and with caution because of the risk of airway obstruction in patients with large neck hematomas. Cervical spine immobilization is not necessary in knife injuries, and though gunshot wounds to the spine can cause fractures, in neurologically intact patients, they rarely are unstable.


Airway compromise may occur because of an external compressing hematoma, a laryngotracheal hematoma, or a major open wound of the larynx or trachea. Orotracheal intubation can be a difficult and potentially dangerous task in the prehospital environment and should not be undertaken lightly.


The initial assessment in the emergency department should always follow ATLS guidelines. Approximately 10% of penetrating neck injuries present with airway compromise. Endotracheal intubation should be attempted only in the presence of a surgeon who can perform a cricothyroidotomy, in case of intubation failure. In fairly stable patients with airway compromise, fiberoptic nasotracheal intubation should be attempted first. For attempted orotracheal intubation, muscle relaxants should be used only in selected cases and by physicians with significant intubation experience, because of the risk of airway loss. On the other hand, intubation without pharmacological paralysis may aggravate bleeding and airway obstruction due to patient coughing and straining, and thus the optimal method of airway establishment should be individualized.


Any external bleeding is controlled by direct pressure or by balloon tamponade using a Foley catheter. In order to avoid air embolism, patients with suspected venous injuries should be put in the Trendelenburg position. Intravenous lines should be avoided on the same side as the injury because of the possibility of a proximal venous injury.


Patients arriving in the emergency department with cardiac arrest should have an emergency department thoracotomy performed. As part of the resuscitation efforts, inspect coronary veins for air embolism and if air bubbles are seen, the right ventricle of the heart should be aspirated.


Following a careful initial physical examination and appropriate investigations, a decision should be made about operation or observation. The selection of the type of management can safely be made on the basis of a good clinical examination and appropriate investigations.



Tips and Pitfalls




  • Do not attempt pharmacological paralysis for emergency endotracheal intubation in the presence of a large neck hematoma without being ready or having the skills for a cricothyroidotomy. If the vocal cords cannot be visualized, the loss of airway may be catastrophic!



  • Do not insert a nasogastric tube in an awake patient in the presence of a large neck hematoma or suspected vascular injury. Straining and coughing may precipitate bleeding. If a nasogastric tube is needed, wait until the patient is anesthetized.



  • Do not insert an intravenous line in the arm on the same side as the neck injury. Any infused fluids may be extravasated from a more central injury. Always use the opposite side.



  • It is recommended to perform a clinical examination according to a written protocol. The inexperienced physician can easily miss important signs and symptoms or neck trauma.



  • Consider neck vascular injuries (carotid or vertebral artery) in patients with unexplained neurological findings.



Penetrating Neck Injuries



Anatomical Zones of the Neck


The description of penetrating neck injuries according to zones is useful in the evaluation and management of the patient. The incidence of significant injuries with zone I wounds is about 15%; in zone II, 25%; and in zone III, 25%. About 15% of patients with zone I or II injuries, and 5% with zone III injuries, require surgical intervention. Also, vascular evaluation in zones I and III is more difficult than in zone II. The vessels in these areas are not easily accessible to color flow doppler studies, and CT angiographic evaluation is the investigation of choice. It is important to remember, however, that the trajectory of the penetrating wound cannot be determined based on the zone of entry, and injuries can often traverse multiple zones, despite the presence of a small entry wound (Figure 3.1, Figure 3.2 A,B, Figure 3.3 A,B, Figure 3.4 A,B).





Figure 3.1 Anatomical zones of the neck. Zone I is confined between the clavicle and the cricoid cartilage, zone II between the cricoid and the angle of the mandible, and zone III between the angle of the mandible and the base of the skull.





Figure 3.2 A,B Zone I penetrating injuries. Stab wound (A). Gunshot wound, associated with large hematoma (B).





Figure 3.3 A,B Zone II penetrating injuries. Knife wound (A). Gunshot wound (B).





Figure 3.4 A,B Patients with zone III stab wound to the neck.



Epidemiology of Penetrating Neck Trauma


Overall, about 35% of all gunshot wounds and 20% of stab wounds to the neck result in significant injuries to vital structures. Transcervical gunshot wounds are associated with the highest incidence (75%) of significant injuries. The most commonly injured structures are the vessels (about 20% of patients), followed by the spinal cord, aerodigestive tract, and nerves (about 5–10% each).


Overall, only about 20% of gunshot wounds and 10% of stab wounds require operation. Some patients with significant vascular injuries may be managed with angiointervention. The remaining patients can be managed nonoperatively.



Physical Examination of Penetrating Injuries of the Neck


Physical examination is very reliable in diagnosing or highly suspecting significant injuries requiring surgical intervention. In order to avoid missing significant signs or symptoms, it is strongly recommended to perform the examination according to a written protocol.


Asymptomatic patients are highly unlikely to have any significant trauma requiring surgical treatment. Depending on the findings of clinical examination, a CTA or color flow doppler may be indicated (Table 3.1, Figure 3.5).




Table 3.1 Physical examination protocol for penetrating injuries of the neck



















A. URGENT PRIORITIES
□ Control any active bleeding (pressure, packing, Foley’s catheter)
□ If active bleeding: Trendelenburg position to prevent air embolism
□ Secure airway
□ IV fluids (in zone I injuries, no IV line on the side of the injury)






























B. SYSTEMIC EXAMINATION
□ Dyspnea □ yes □ no
□ Blood pressure
□ Pulse
□ Color □ pale □ normal








































C. LOCAL EXAMINATION
Vascular structures
□ Active bleeding □ minor □ severe □ no
□ Expanding hematoma □ small □ large □ no
□ Pulsatile hematoma □ yes □ no
□ Peripheral pulses (compare with normal side,doppler?) □ normal □ diminished □ absent
□ Bruit □ yes □ no






























D. LARYNX – TRACHEA – ESOPHAGUS
□ Hemoptysis □ yes □ no
□ Air bubbling through wound (ask patient to cough) □ yes □ no
□ Subcutaneous emphysema □ yes □ no
□ Pain on swallowing sputum □ yes □ no





















































































E. NERVOUS SYSTEM
□ Glasgow Coma Scale
□ Localizing Signs
□ Cranial nerves
Facial nerve □ yes □ no
Glossopharyngeal nerve □ yes □ no
Recurrent laryngeal nerve □ yes □ no
Accessory nerve □ yes □ no
□ Spinal cord
□ Brachial plexus injury □ normal □ abnormal
Median nerve □ yes □ no
Ulnar nerve □ yes □ no
Radial nerve □ yes □ no
Musculocutaneous nerve □ yes □ no
Axillary nerve □ yes □ no
Homer’s syndrome □ yes □ no


















F. INVESTIGATIONS (only in fairly stable patients) Chest X-ray (erect)
□ Hemopneumothorax
□ Subcutaneous emphysema
□ Widened upper mediastinum
□ Retained knife blade or missile




Figure 3.5 Horner’s syndrome after penetrating trauma in zone I. It consists of ptosis of the upper eyelid (arrow) and miosis of the ipsilateral eye. It is the result of injury of the stellate ganglion (on the neck of the first rib) of the sympathetic chain.




Table 3.2 Algorithm for the Management of Penetrating Injuries of the Neck












Radiological Investigations for Penetrating Neck Trauma



Plain Radiography

Anteroposterior and lateral X-rays of the neck are rarely useful in patients with penetrating neck trauma. If done, important radiological findings include hematoma, subcutaneous emphysema, fractures, and foreign bodies. A chest X-ray, however, is recommended in all stable patients. In about 15% of patients with penetrating neck trauma, there is an associated pneumothorax or hemothorax. A widened upper mediastinum is suggestive of a hematoma secondary to a vascular injury, and an elevated diaphragm may be due to a phrenic nerve injury (Figure 3.6, Figure 3.7, Figure 3.8, Figure 3.9).





Figure 3.6 Plain X-ray of the neck shows two bullets, one in zone I and another in zone III.


Apr 22, 2021 | Posted by in EMERGENCY MEDICINE | Comments Off on Chapter 3 – Neck Injury
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