4. Acute C2 injury Flashcards
You are asked to anaesthetise a 68-year-old patient for fixation of an unstable C2 fracture.
Discuss the anaesthetic management.
This patient is going to have a difficult airway.
The fracture is either due to trauma, in which case the patient may have other injuries,
or it may be due to an underlying medical condition such as rheumatoid arthritis.
There are several important issues that require more information, both
from the patient and the surgeon.
An ABC approach to the pre-op assessment may be useful:
Airway + Breathing
Airway –
the neck will be immobilised in,
for example, a hard collar
(mouth opening limited)
or a halo (unobstructed mouth opening). A thorough
airway assessment is essential.
Breathing – Has the patient any associated chest injuries?
Does the patient look easy to ventilate?
Has the patient got a cord injury that has compromised ventilation?
Consider post-operative respiratory monitoring or
support with high cervical lesions affecting the intercostal or phrenic nerves.
Circulation
Neuro
Associated injuries
Circulation –
there is a possibility of cardiac arrhythmia and autonomic dysfunction
(hypotension with lesions above T6, bradycardia with lesions above T1).
Neurological assessment and documentation of any deficit is vital.
Associated injuries –
a secondary survey should have been completed (10%
of patients will have another vertebral column fracture).
Other info
Surgical approach
Other usual pre-op information should be sought in terms of previous GAs,
allergies, past medical history, etc.
Proposed surgical plan
Approach – anterior (via neck or mouth) or posterior or both
Positioning – supine or prone
Some patterns of spinal cord injury:
Complete injury Motor and sensory loss below a certain level
Central cord Arms paralysed > legs
Variable sensory disturbance
Bladder dysfunction
Anterior Cord
Posterior Cord
Anterior cord
Paralysis below level of lesion
Proprioception, touch and vibration sense preserved
Posterior cord
Touch and temperature sensation impaired
Hemisection
Hemisection Brown–S´ equard syndrome:
Ipsilateral paralysis, loss of proprioception, touch
and vibration sensation
Contralateral loss of pain and temperature
sensation
Would you use an arterial line?
Yes. Invasive monitoring is necessary with cord compromise.
Spinal cord perfusion pressure will be affected
by both oedema and anatomical displacement
and any drop in mean arterial pressure (MAP) could compromise
the cord further.
In addition, prone positioning can affect MAP and cord perfusion.
Spinal cord monitoring
Increasingly used.
Evoked potentials – motor and sensory can be used.
These are affected by volatile agents and NMBs.
The spinal cord is most likely to suffer ischaemic events at C2/C3.
How would you manage the patient’s airway?
This depends on the immobilisation measures in place,
the degree of cord compromise and the risk of aspiration.
The proposed technique should be discussed with the surgeon.
Skull traction or a Halo frame limits neck movements,
while full immobilisation in a hard collar with sandbags limits
both neck movement and mouth opening.
Awake fibre-optic intubation (AFO) is probably the technique of choice for a number of reasons:
Why AFOI
Any risk?
Minimises neck movements.
Does not necessitate good mouth opening.
Checking for intact neurological function immediately after intubation
helps to exclude this as a cause of any post-operative neurological deterioration.
AFO in these patients is, however, not without potential problems as coughing
may be disastrous in this setting.
Careful preparation with local anaesthesia and the judicious use of opioids such as a Remifentanil infusion will help to suppress coughing.
An experienced operator is essential.
If the stomach is empty and the airway accessible,
the following may be considered:
Asleep fibre-optic intubation (+/− LMA or ILMA)
Standard laryngoscopy with cervical spine immobilisation
Is there any problem using certain muscle relaxants?
Suxamethonium can potentially cause hyperkalaemia by an exaggerated
release of potassium ions from denervated muscles,
especially if surgery occurs >72 hours after the injury.
NMBs will interfere with spinal cord monitoring – see box below.
If the surgeon wants to position this patient prone, what are the considerations?
- The deleterious effects of prone positioning are:
V/Q mismatching
Reduced venous return
Reduction in cardiac output - General precautions:
Meticulous care of pressure points
Ensure that the abdomen is free for respiration
Avoid pressure on the eyes - Specifically for this procedure:
More personnel will be required for a log roll to ensure
that the axial skeleton remains neutral.
A plan for fixing the head in position
(usually involving a Mayfield frame)
must be made.
Eye injury under anaesthesia
- Corneal abrasion –
drying/eyes not taped –
may take months to heal. - Ischaemic optic neuropathy (ION) –
more common with prone position
as increased intra-ocular pressure.
Not due to external pressure. - Central retinal artery occlusion (CRAT) –
caused by external pressure
(often due to horseshoe headrest)
or emboli from the carotid artery.
What would you use for post-operative analgesia?
The surgeons use local anaesthetic with adrenaline to vasoconstrict the
operative field
and longer-acting local anaesthetic could be instilled at the
end of surgery.
Regular paracetamol in addition to PCA morphine will provide adequate analgesia.
NSAIDs should be carefully considered after discussion with the surgeon,
as a haematoma could be catastrophic for the patient.
