Penetrating neck injury

Question 7 from the second paper of 2015 asked not only about the management of neck trauma, but also about the details of neck anatomy. This was a complete loss for many candidates. We tend to lose interest outside the collapsible venous structures. As anything which had a pass rate of 27%, this topic merits a more detailed look, in case it ever appeared again (it would be embarrassing to fuck it up for the second time, the author reasoned). Appear it did, as Question 9 from the first paper of 2018, which was totally identical and where the pass rate was again 26.5%.  The examiners again complained that nobody knew the anatomy. Obviously this is a subject matter which is expected to discriminate good intensivists from bad. 

For an excellent revision of the important issues, the interested trainees are directed to Karim Brohi's 2002 write-up of neck wounds on trauma.org.  Its free and it actually beats the coin-operated resources in terms of detail and information density. Much of the information in this chapter is derived from Brohi. Colourful embellishment was then added from the UpToDate article on penetrating neck injury.

Anatomy at the root of the neck

The college lists the contents in order of anterior to posterior in their model answer. Thus, the possible injuries would be to the following structures:

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

Specific injury patterns in penetrating neck trauma

Airway damage in penetrating neck trauma

• Features suggestive of this:
  • hoarse voice
  • stridor
  • haemoptysis
  • subcutaneous emphysema
• Manipulation of the airway could lead to complete transection. Ergo, ideally an ENT surgeon or somebody equally skilled in surgical airways should do the instrumentation.

Vascular damage in penetrating neck trauma

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

Oesophageal injury in penetrating neck trauma

• Features of this:
  • Haematemesis
  • Painful swallowing
  • subcutaneous emphysema
• Endoscopy and/or gastrograffin swallow are the imaging modalities of choice; however with endoscopy the insufflation of the oesophagus may worsen the subcutaneous emphysema
• According to Brahi, each modality alone has a sensitivity of around 80-90%, while combined they have a sensitivity of approximatly 95%
• A high-resolution CT may be the ideal modality now (Brohi was writing in 2002). According to modern authors (eg. Offiah et al, 2012) these days a good CT scanner will tell you everything you need to know

Neurological injury in penetrating neck trauma

• Penetrating injuries to the neck do not require spinal immobilisation
• Stab injuries are not associated with spinal instability.
• Gunshot wounds will usually be associated with complete cord transection, if they cause any spinal trauma at all.
• Spinal nerve roots are more commonly injured than the cord itself
• Brachial plexus injuries ae fairly common, especially if a vascular injury is present (Zone I trauma)
• Recurrent laryngeal nerve trauma will manifest as hoarseness
• Phrenic nerve trauma will manifest as an elevated hemidiaphragm
• Horner's syndrome may develop

Management issues  in penetrating neck trauma

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