Spinal cord injury

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    Introduction

    Spinal cord injury should be suspected in any child who has:

    • Multi system trauma,
    • Minor trauma associated with spinal pain,
    • Sensory or motor symptoms, or
    • Altered consciousness.

    The patient must be adequately immobilised, for example, on a spinal board with a cervical collar and head immobiliser ( see cervical spine assessment clinical practice guideline). Any assessment of the back, or of patient movement, must be accomplished by logrolling. Recent figures suggest that up to 50% of patients with spinal cord injury will have at least moderate head injury.

    In all aspects of trauma management, the primary survey is the first priority

    Primary survey

    The most immediate threats to life and spinal cord function of patients with spinal cord injury are always hypoxia and hypotension.

    • Spinal cord lesions in the upper cervical spine may impair respiratory function and require early intubation and mechanical ventilation.
    • The unstable cervical spine must be maintained in alignment, without traction, during treatment of the airway.

    Neurogenic Shock

    • Is the manifestation of loss of sympathetic output to the cardiovascular system?
    • Is seen immediately after complete cord injury at the level of T6 or above.
    • The loss of sympathetic vasomotor tone after cervical spinal cord injury will result in vasodilatation, venodilatation, and reduced venous return to the heart, causing hypotension.
    • Neurogenic shock can be more easily distinguished from haemorrhagic shock where there is an associated relative bradycardia for age.

    Neurogenic shock should not be confused with Spinal Shock

    Spinal shock

    Spinal shock is the reversible dysfunction of the spinal cord associated with injury

    • Which is like a concussion of the cord without permanent damage;
    • Which may exist alone, or in combination with permanent cord injury.
    • Which, in resolution, produces the improvement in neurologic function seen in the first few days post injury.

    Secondary survey

    Examination of neurologic impairment is done as part of the secondary survey.

    • A thorough examination of the motor function of the limbs and assessment of reflexes should be performed.
    • Establishment of a level of sensory deficit.
    • Knowledge of the dermatomes and myotomes, to allow determination of the level of neurological injury.

    Partial spinal cord injury:

    • There is preservation of some motor or sensory function below the lesion;
    • Many patients will regain most or all of their neurologic function;
    • A partial cord injury may occur at any region and with any mechanism of injury.

    Complete spinal cord injury:

    • Is most commonly seen in injuries of the thoracic spine and thoracolumbar junction. The spinal cord is large in relation to the size of the spinal canal at this level.
    • If still present at 24 hours, rarely recover to any significant level of function.

    Cauda equine lesions

    • Injuries at or below L2;
    • Involve the peripheral nerves rather than the spinal cord; and
    • Can show significant recovery of lower limb and sphincter function, even weeks after the injury.

    Management

    • Initial fluid resuscitation with 10 - 20 ml/kg should be adequate to replace the relative hypovolaemia.
    • But if hypotension persists, measurement of central venous pressure (CVP) may be needed to guide fluid-replacement.
    • Excessive fluid replacement that pushes central venous and pulmonary artery pressures above the normal range will result in pulmonary oedema.
    • Treatment with a vasoconstrictor, such as metariminol, may be useful for the patient who has adequate CVP and remains hypotensive.
    • Bradycardia - where there is also significant bradycardic, inotropic agents such as dopamine or adrenaline may be useful.

    Patients requiring more than 40 ml/kg of fluid replacement, and having a low CVP, must be assumed to have other injuries causing blood loss.

    Radiographic evaluation

    In all patients with suspected spinal cord injury, the spine should be x-rayed.

    • The radiographs should include the entire spine, as multiple levels of injury are common.
    • Once the patient is stabilised, further investigation of the lesion should follow. Bony injuries should be investigated. See Chapter 1.19
    • Investigation of the cord itself will require MRI. -MRI should be performed as soon as possible after identification of a spinal cord injury. -MRI will allow identification of remedial intraspinal problems in patients with a partial neurologic deficit.
      • The appearance of the spinal cord on MRI also allows prediction of neurological outcome:
    • Cord transection and major haemorrhage have a poor outcome,
    • Minor haemorrhage and oedema have a moderate to good outcome,
    • Normal MRI is associated with complete recovery.

    Sciwora - spinal cord injury without radiographic abnormality

    Spinal cord injury without radiographic abnormality is present when there are objective signs of myelopathy as a result of trauma, with no evidence of fracture or ligamentous instability on plain x-rays or CT.

    • SCIWORA is most frequently seen in younger children (especially <8 years of age), and in injuries of the cervical spine.
    • Postulated causes include
      • Ligamentous laxity and bony immaturity allowing excessive, transient movement during trauma causing distraction or compression of the spinal cord;
      • Cord ischaemia due to vascular injury or hypoperfusion.
    • The incidence reported in children ranges from 1% to 10% of all spinal cord injuries.
    • Younger children tend to have more profound neurological injury, and hence less long-term improvement.
    • A number of children will present with minor neurological injury and progress to complete or partial spinal cord injury. -The incidence of this delayed presentation of the serious symptoms is reported to be between 5 and 50%.
      • The delay to presentation of full symptoms has been as long as 4 days.

    Because of these delayed presentations, all children with symptoms of any neurologic deficit should be treated as potential spinal cord injuries.

    Treatment

    Most of the treatment available for spinal cord injuries is supportive. The breathing and circulation must be supported as needed.

    • Catheter - as there will be a neurogenic bladder, catheterisation is necessary.
    • Nasogastric tube - is needed to treat the gastric and bowel stasis that ensues.
    • Anti-emetic - (for transport) , is useful to prevent vomiting and spine movement or airway compromise.
    • Heparin - subcutaneous low-molecular-weight heparin should be instigated once the patient is stable, to prevent deep venous thrombosis.

    Specific treatment of the spinal cord lesion is controversial.
    Four substances have been studied in prospective, randomised trials

    • Methylprednisolone,
    • Tirilazad, naloxone
    • GM-1 ganglioside.

    All studies to date have excluded children under 13 years of age.

    1. Methylprednisolone

    • There is conflicting evidence regarding the benefits of methylprednisolone, and some documented evidence that it increases the risk of bacterial infection.
    • It is recommended that it be used only with knowledge of the risks and possible benefits. It must be instituted within 8 hours of the injury. The current regimes for use are seen below

    Methylprednisolone Administration in  cervical spine assessment clinical practice guideline

      Time after injury   
      0-3 hours  3-8 hours  >8 hours 
    Initial i.v. dose  30mg/kg (over 15 mins)  30mg/kg (over 15 mins)    Not Recommended
    Maintenance i.v. dose   5.4 mg/kg/hr  5.4 mg/kg/hr    
    Duration  24 hours  48 hours   

    2. Tirilazad and Naloxone

    • Tirilazad and naloxone have failed to show any benefit in trials to date.

    3. GM-1 ganglioside

    • GM-1 ganglioside has yet to be shown to offer significant benefit in spinal cord injury, and is not recommended for routine use.

    Transfer

    Once the patient has been stabilised and investigated, transfer to a spinal cord injury unit should be expedited. Consultation with the spinal service should be made early.

    • These units and associated intensive care units are geared to manage
      • The cardio-respiratory compromise that may occur in the
        ensuing weeks,
      • The psychosexual issues that accompany spinal cord injury,
      • The associated urological problems, and
      • The potential for skin breakdown that are exaggerated in
        these patients.