You have been called to the Emergency Department to review a previously well adult male who has sustained a penetrating injury to the root of the neck.

a)    Describe the anatomy of the root of the neck on the left side describing the clinically important
    structures that may be injured.    (50% marks)
b)    Outline the issues specific to management of a penetrating neck injury.    (50% marks)

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College answer

a)

The root of the neck is the junction between the thorax and the neck. It opens into, and is the cervical side of, the superior thoracic aperture, through which pass all structures going from the head to the thorax and vice versa

 The root of the neck is bound laterally by the first rib, anteriorly by the manubrium, and posteriorly by the T1 vertebrae.  

From anterior to posterior, the major contents are:          

  • Subclavian artery and branches 
    • vertebral artery
    • internal thoracic artery
    • thyrocervical trunk
    • costocervical trunk
  • Subclavian vein and tributaries (EJV)
  • Trachea
  • Oesopahagus
  • Vagus nerve
  • Recurrent Laryngeal nerve
  • Dome of pleura
  • Brachial plexus
  • Lymphatics and thoracic duct
  • Phrenic nerve 
  • Sympathetic chain, stellate ganglion
  • Scalene muscle.
  • Clavicle

b)

  • Requires management at a trauma centre with appropriate expertise. May require multiple speciality input - interventional radiology, ENT, vascular, cardiothoracic.
  •  Airway issues: The possibility of laryngeal/ tracheal injury and the risk of intubating the “false airway passage”. Consider tracheostomy under local anaesthesia.
  •  Urgent surgical exploration required for haemodynamic compromise, expanding or pulsatile haematoma, extensive subcutaneous emphysema, stridor, or neurological deficit with intra op bronchoscopy/ endoscopy/ angiography if available. 
  •  If no indication for urgent surgical exploration requires CT angiography (or equivalent) with close observation in ICU +/- flexible laryngoscopy +/- endoscopy +/- oral contrast swallow study.

Examiners Comments:

 

Generally, poorly answered. Limited knowledge of anatomy and poor structure to answers. A broad approach with a logical approach to prioritisation of investigations/treatments was all that was required to score well. Few candidates commented on general principles of complex trauma requiring input from multiple teams.

Discussion

This queestion is identical to Question 7 from the second paper of 2015, except this time you have been called to the Emergency Department, not the Emergency Room.  Again, the pass rate was under 30%. For future reference, neck anatomy and penetrating neck injury is described in excellent detail by Phillip Thorek in his chapter for Anatomy in Surgery (1985) which is unfortunately paywalled by Springer. So is "Trauma to the neck region"  by Saletta et al (1973) and the UpToDate article on penetrating neck injury. For the freegan,  Karim Brohi's 2002 write-up of neck wounds on trauma.org is of a high quality.

Brohi divides the neck into three zones, each with its own specific concerns:

(image from trauma.org)

Zone 1:
Extends from the clavicles to the cricoid cartilage.

  • subclavian and innominate vessels
  • common carotids
  • lower vertebral arteries
  • jugular veins
  • Thoracic duct (on the left)

Zone 2

Extends from the cricoid cartilage to the angle of the mandible.

  • Common carotid
  • carotid bifurcation,
  • vertebral arteries
  • jugular veins.

Zone 3

Extends from the angle of the mandible to the mastoid process.

  • branches of the external carotid artery,
  • internal carotid artery,
  • vertebral artery
  • internal jugular vein
  • facial vein

Specific concerns:

  • massive haemothorax
  • arteriovenous fistula
  • Thoracic duct damage
  • brachial plexus damage
  • Angiography is very important; occlusion balloons may be very useful in controlling haemorrhage

Specific concerns:

  • little to gain from angiography; angioembolisation could result in disastrous strokes
  • Physical examination is sufficient
  • Haematoma expansion should be monitored

Specific concerns:

  • angiography may be useful
  • angioembolisation of the branches of the external carotid is feasible
  • with vertebral artery damage, a hemi-cord syndrome (Brown-Sequard) may develop

So, this question is about Zone 1, where all the important stuff is. 

b)

A generic approach to management:

  1. Assess for airway compromise (eg. by expanding haematoma)
    Assess for airway injury (eg. subcutaneous emphysema)
    Organise expert help.
    Awake fiberoptic intubation by an experienced operator would be ideal, with an ENT surgeon on standby. Risks include intubating a false passage, or causing complete tracheal disruption.
  2. Assess for respiratory compromise.
    Ausculation and percussion may reveal pneumothorax due to injury of the dome of pleura, or the raised hemidiaphragm of a phrenic nerve injury
  3. Assess the circulation in the arm on the affected side. There may be vascular compromise.
  4. Assess the neurology of the patient, starting with GCS.
    Verterbral artery damage may present with spinal syndromes (eg. Brown-Sequard) or brainstem stroke signs
    Carotid artery damage may present with hemispheric stroke signs

Reasons for urgent surgical exploration:

  • airway compromise (stridor, etc)
  • haemorrhgic shock
  • expanding haematoma (or, especially if it is pulsatile)
  • stroke-like symptoms

Additional concerns specific to the root of the neck:

  • massive haemothorax
  • arteriovenous fistula (subclavian vessels)
  • Thoracic duct damage (if it was the left side of the neck, as it tends to be with a right-handed attacker coming from the front)
  • brachial plexus damage
  • Horner's syndrome

References

Thorek, Philip. "Root of the Neck." Anatomy in Surgery. Springer, New York, NY, 1985. 247-251.

Saletta, John D., Frank A. Folk, and Robert J. Freeark. "Trauma to the neck region." Surgical Clinics of North America53.1 (1973): 73-86.