1. Anatomy and Physiology of the Vertebral Column and Spinal Cord

The spine is central to the skeletal system supporting the head and enclosing the spinal cord.

Running down the centre of the spine, or vertebral column, is the spinal cord. No thicker than your finger, the spinal cord is protected by the vertebrae and the surrounding muscle and ligaments.

The cord, which is extremely delicate and vital to the total functioning of the body, is made up of millions of nerves which are the communication link between the brain and all other body parts. This two way cable system picks up the incoming messages from the arms, skin, feet, etc. and transmits them to the brain. At the same time the brain also sends out messages which are transmitted to the different muscle and body functions.

The cervical nerves are responsible for movement and sensation in the upper limbs, neck and upper chest. The thoracic nerves are responsible for movement and sensation in the trunk and abdominal region. Nerves in the lumbar and sacral areas are responsible for movement and sensation in the lower limbs and bladder, bowel and sexual functions.

Damaged nerves may survive and function, but once destroyed will never recover or be replaced.

2. Recognition of Spinal Injury

The types of trauma most likely to result in spinal fracture and neurologic deficit are: automobile, motorcycle, ATV (all-terrain vehicles) and snowmobile accidents, diving injuries, cave-ins, all codes of football and falls from heights. With a head injury or in any unconscious patient, assume that there may be a spinal injury.

All head injuries should be considered spinal injuries until proven otherwise.

3. When to Transport

All patients with recognised spinal injury are candidates for transport to a Spinal Unit. Transport should take place as soon as spinal injury is recognised and immediate life-threatening problems, such as airway compromise and haemorrhage have been stabilised. Definitive care for associated injuries should, in most instances, be deferred until after transport to the Spinal Unit.

B. STABILISING AND PREPARING THE PATIENT FOR TRANSPORT

1. Resuscitation

Immediately following an acute traumatic spinal cord injury, hypotension and hypoventilation may threaten life and/or increase the extent of neurological impairment.

Therefore, cardiorespiratory resuscitation and stabilisation of all other life-threatening injuries are the first steps in the treatment of acute spinal cord injured patients.

Resuscitation techniques must at times be modified to ensure that any spinal fractures remain as stable as possible, so that further neurological damage does not occur.

The aim is to transport the patient in the supine ("eyes up") position.

2. Respiratory Insufficiency

1. Establish Airway (with cervical spine control)

   Injuries of the cervical spine are commonly associated with airway obstruction and hypoventilation. If the patient is unconscious, the tongue may passively fall backward occluding the oropharynx.

   Airway patency can be restored by either the modified jaw thrust manoeuvre or by pulling the mandible forward (without inadvertently extending the neck) and then inserting an oropharyngeal airway over the tongue, whilst an assistant maintains the head in the NEUTRAL POSITION.

   Hypoventilation is common in patients with thoracic injuries and loss of respiratory musculature.

   Ventilatory assistance may be required in these patients, usually with tracheal intubation. Measuring and recording the patient's Vital Capacity is very helpful.

   A semi-rigid cervical collar such as the Ambu or Stifneck collar should be applied as soon as cervical injury is suspected.

   Steps in intubation (oral) are:

   (i) Pre-oxygenation: 100%0₂ via bag and mask
   (ii) Cricoid Pressure: during pre-oxygenation and until intubation is complete (to prevent regurgitation and gastric insufflation).
   (iii) Manual Axial Support (NOT TRACTION) by an assistant holding the head in the NEUTRAL POSITION throughout.
   (iv) Oro-tracheal intubation in the usual manner.
   (v) Blind Nasal Intubation may be performed by a suitably experienced anaesthetist.
   (vi) A surgical airway (cricothyroidotomy or tracheotomy) is an emergency alternative when intubation is not possible.

   NB. A retropharyngeal haematoma associated with a major injury of the upper cervical spine may also cause upper airway obstruction and

   necessitate intubation or creation of a surgical airway.

2. Oxygen Therapy

   Determination of arterial blood gases via oximetry or invasive means is an essential part of the initial management of cervical and thoracic spinal cord injuries. Because of local oedema and haemorrhage, spinal cord oxygen tension may quickly fall below normal tissue requirements even without systemic hypoxaemia.

   Systemic hypoxaemia may increase the severity of a spinal cord injury and attempts should be made to maintain arterial oxygen tension at or above 80mmHg

   Oxygen should be delivered by a high concentration mask (50-60% unless contraindiated by chronic respiratory illness) using 100% oxygen at high flows (10-12 litres per minute). In the absence of high concentration masks or a non-rebreathing mask, a Hudson mask will suffice.

   If oxygen supplementation by face mask is inadequate, careful intubation and ventilatory assistance is indicated.

   The use of Hyperbaric Oxygen Therapy is an additional treatment modality aimed at preventing hypoxia at the tissue level, and should ideally be commenced WITHOUT DELAY (preferably within a few hours).

3. Ventilatory Assistance

   The most reliable sign of impending ventilatory decompensation is a respiratory rate greater than 35 per minute. Ventilatory assistance should be considered before the patient's respiratory rate gets this rapid.

   Altered consciousness, apparent drug or alcohol intoxication, systemic hypoxaemia or hypercarbia (C_O2 over 40mmHg) are also indications for assisted ventilation.

   Endotracheal intubation is recommended for any patient requiring ventilatory assistance.

4. Chest X-Ray

   Radiographic evaluation of the chest is essential prior to transport of any patient with cervical or thoracic spinal cord injury, because of the

   frequency of associated chest injuries, particularly pneumothorax.

   If a pneumothorax is present, a chest tube must be inserted before transport.

   A Heimlich valve is mandatory.

3. Circulatory Insufficiency

1. Differentiate Hypovolaemic from Neurogenic Shock

   In cervical and thoracic spinal cord injuries, Neurogenic shock with bradycardia and hypotension are common.

   In Neurogenic Shock, unlike Hypovolaemic Shock, the pulse rate is slow and of good amplitude and the skin is usually warm and dry except if the patient has been exposed to a cold environment (see 5). Tachycardia and clammy skin are seen in hypovolaemia.

   Neurogenic and Hypovolaemic shock may coexist.

   When this happens, Neurogenic shock exacerbates the effects of Hypovolaemic shock by disabling the vasoconstrictive reflexes that ordinarily preserve blood flow to vital organs.

2. Intravenous Lifelines

   Two intravenous lines, preferably 14 or 16 gauge, should be established for administration of resuscitation fluids and medications.

   The maintenance of tissue perfusion cannot be over-emphasised. Spinal cord ischaemia may be due to hypotension (either from spinal shock or hypovolaemia) and can cause increased cord damage and extend the neurological deficit.

   In the absence of overt Hypovolaemic shock, Hartmann's solution should be infused at a rate sufficient to maintain a systolic blood pressure of above 80mm Hg, generally 50-100ml per hour.

   Pressor agents are rarely necessary and should be administered only if the central venous pressure indicates satisfactory intravascualr volume.

   Neurogenic Shock with associated Hypovolaemic Shock should be treated with Normal saline or Hartmann's solution in order to increase the intravascualr volume and blood pressure. Intractable hypotension should raise the possibility of concealed internal haemorrhage.

   Sinus bradycardia down to 50 associated with cervical spine cord injury does not require specific therapy.

   With rates below 50, nodal or ventricular "escape" rhythms emerge that can be corrected with Atropine (0.5-1.0mg) administered as often as necessary up to 2.0mg per hour.

   NB. normal quadraplegic BP range 80/40 - 100/60

   DO NOT FLUID OVERLOAD: Cord oedema and reduced perfusion will result.

4. Spinal Splinting

The key to proper management of spinal trauma is to recognise that an unstable spine may exist.

Patients who arrive in the emergency department with neck already immobilised in the supine position should not be removed from the spinal splint until the extent of the injury is determined.

Inadvertent movements of the neck must be prevented during resuscitation.

The preferred means of rapidly and safely immobilising the neck from flexion and extension is to apply a semi-rigid cervical collar, such as the Ambu or Stifneck.

Lateral cervical immobilisation also needs to be maintained. This can be accomplished using blanket rolls, a blanket halo, Russell Extrication Device (R.E.D) or other type of immobilisation boards.

5. Impaired Temperature Regulation

The temperature of patients with cervical spinal cord injuries tends towards that of their immediate environment (Poikilothermia).

Body temperature should be determined regularly (orally should suffice), and in most acute cases the patient should be kept covered and warm. "Space blankets" can be of great value in these instances.

6. Internal Injuries

Loss of sensation over the thorax, abdomen or limbs is often associated with altered sensation from abdominal viscera or skeletal structures.

Thus, injuries to all but the most caudal segments of the spinal cord may abolish the spontaneous pain, tenderness to palpitation, local guarding, or generalised rigidity which are often present with other intraabdominal injuries.

Spinal cord injury alone can also produce the auscultatory and radiographic signs of ileus, within 30mins-48 hours of injury.

Patients should be transported supine with a Nasogastric Tube on continuous drainage (with suction if required).

Hypotension combined with tachycardia is seldom, if ever, attributable solely to spinal cord injury.

In the absence of other overt sources of haemorrhage, investigation of potential abdominal sources of haemorrhage by diagnostic peritoneal lavage or CT should be undertaken under these circumstances, as well as a secondary survey of other systems for missed sources.

C. NEUROLOGICAL EVALUATION

The physician that first sees the patient should document the extent of the initial neurological deficit and determine the presence of any associated injury to the vertebral column.

1. Diagnosis of Spinal Cord Injury

Signs and symptoms of spinal cord injury are usually readily apparent in the alert patient, but can be obscured by altered consciousness.

The following clues should alert the physician to the possibility of a spinal cord injury in an unconscious patient.

1. A cervical spinal cord injury should be suspected if an unconscious patient grimaces, vocalises or opens his eyes in response to pinching the border of his trapezius muscle but does not move his limbs.

   Similarly, a patient who moves both arms but neither legs in response to noxious local stimuli may have a spinal cord injury below the cervical level. Corroborative findings often include hypo- or areflexia and flaccidity of the paralysed limbs, a flaccid anal sphincter, or priapism.

2. "Paradoxical Respiration"

   In this condition, the thoracic cage, although stable, passively collapses with inspiration (as the diaphragm contracts) and expands with expiration (as the diaphragm relaxes) in a reversal of the normal cycle of thoracic ventilatory movements. This pattern of breathing should be looked for carefully and differentiated from bilateral flail chest, in which there will be instability of the chest wall.

3. Hemiparesis opposite pinprick hemianaesthesia suggests cord injury. Both head and spinal injuries can cause hemiplegia, but only spinal injuries routinely produce contralateral hemimotor and hemisensory deficits. (Brown-Sequard Syndrome).

4. In a cervical injury where central fibres only are damaged, the Central Cord Syndrome results (upper limbs paralysed, lower limbs less/not affected).

2. Documentation of the Neurological Deficit

Management of spinal cord injured patients depends to a large extent upon whether the patient has a Complete or Incomplete physiological transsection of the spinal cord, and if incomplete, whether the neurological deficit is progressing or resolving with the passage of time.

The first step in determining whether the patient is deteriorating, improving or stable is to question him/her (and ambulance personnel or members of the rescue squad) about limb movement and sensation immediately after the injury.