Spinal cord injury

 

Spinal cord injury (SCI) is a relatively rare, but potentially devastating diagnosis with life-long consequences. There are approximately 80-130 new cases of SCI in New Zealand per year.¹ The majority of patients are males aged 24-45 with 40% of injuries resulting from motor vehicle accidents.

Types of spinal cord injuries

Complete

• Complete injury to the spinal cord
• Loss of motor and sensory function below level of injury, including anal tone
• Bulbocavernous reflex usually absent

Incomplete

• Partial injury to the spinal cord
• Patchy loss of sensation and motor function below this level
• Bulbocavernosus reflex and anal tone often present

Central cord

• Motor function more impaired in the upper limbs as compared to lower limbs
• Patchy sensory change
• Bladder dysfunction common
• Often seen in patients with pre-existing spondylosis (eg: older adults) following seemingly minor hyperextension trauma to the cervical spine

Anterior cord

• Injury to the anterior 2/3 of the spinal cord (eg: from a retropulsed bone fragment)
  • Corticospinal tract – weakness and initial loss of reflexes
  • Spinothalamic tract – bilateral loss of temperature and pain sensation
  • Intact proprioception, vibration and tactile senses
  • Bladder function usually preserved

Brown Sequard Syndrome

• Lateral hemitransection of the spinal cord (eg: from a stabbing or GSW)
  • Ipsilateral loss of power, proprioception and vibration sense
  • Contralateral loss of pain and temperature sensation

Transient paralysis

• Akin to a concussion state of the spinal cord
• Patients can have complete loss of motor and sensory function with absent reflexes, loss of bulbocavernosus reflex and anal tone
• Possibly due to the transient loss of intracellular potassium in the injured cord
• Function can return over hours to days/weeks
  • Sometimes full recovery, other times patient may be left with a degree of spasticity

 

Assessment and initial management

 

In addition to the standard primary survey, the following are important considerations for patients with suspected SCI.

Airway and breathing

Patients with a suspect SCI should be treated with supplemental oxygen as required to treat hypoxia.

The degree of respiratory impairment correlates to the level of the SCI. Patients with high cervical cord injuries can rapidly develop respiratory failure (“C3,4,5 keeps the diaphragm alive”). Patients with lower cervical and upper thoracic SCIs can also have varying degrees of respiratory impairment depending on the level of the lesion.

Signs of impending respiratory failure include

• Tachypnoea
• Poor respiratory effort
  • Loss of diaphragm control can result in “see-saw” breathing – with inspiration the chest is pulled in while the abdomen expands
• Hypoxia
• Hypercapnoea and type 2 respiratory failure

These patients will require early intubation with special precautions

• Maintain strict in line stabilisation of the cervical spine
  • The most experienced operator should intubate
  • If the patient does not require emergent intubation, fibreoptic guided intubation may be the safest option if available (liaise with anaesthesia)
• Laryngeal manipulation in patients with high cervical injuries can cause an increase in vagal tone with subsequent bradycardia. Treat with atropine.

Circulation

Hypotension in patients with SCI at or above T6 can be the result of “neurogenic shock” as the sympathetic outflow is interrupted causing decreased vascular resistance. This is usually associated with bradycardia.

However, hypotension in patients with SCI should be assumed to be from blood loss with a search for the source, until proven otherwise

Patients with concomitant neurogenic and hypovolaemic shock can have falsely reassuring findings – a relative bradycardia and warm peripheries.

Note also that patients with SCI can have an unreliable abdominal examination due to loss of motor tone and sensation. FAST +/-  CT should be utilised to detect occult intraabdominal bleeding as the cause of shock.

Once haemorrhage is excluded, hypotension should be treated with IV fluid and vasopressors (eg: noradrenaline) if required. The BP aims are controversial with many guidelines recommending MAPs between 85-90, however this is level III evidence² and has been questioned^3,4

Note that neurogenic shock different from “spinal shock” – this is not a circulatory shock state, but a term for the loss of motor function and sensation with initial loss but gradual return of reflexes below the level of a SCI injury. This can last for hours to days (or even weeks). Note that patients with spinal shock above T6 can also develop neurogenic shock.

Neurological

Once life threats have been addressed a full neurological assessment should be completed in order to assess the level and severity of the SCI. This can also guide treatment and prognosis.

The ASIA chart should be utilised to document neurological findings

This involves a detailed assessment of sensation and power (including anal tone and the sensation of deep anal pressure) resulting in a score from A to E

A – complete: no sensory or motor function in sacral segments 4-5

Prognosis – 80% remain the sam

B – sensory incomplete: Sensory, but not motor, function is preserved below the neurologic level and extends through sacral segments S4-S5

Prognosis – 80% improve (40% convert to ASIA C, 40% convert to ASIA D)

C – motor incomplete: Motor function is preserved below the neurologic level, and most key muscles below the neurologic level have a muscle grade of less than 3

Prognosis – 60-80% convert to ASIA D

D = Incomplete: Motor function is preserved below the neurologic level, and most key muscles below the neurologic level have a muscle grade that is greater than or equal to 3

Prognosis – many can walk independently

E = Normal: Sensory and motor functions are normal

ASIA impairment scale chart

ASIA

 

 

A log roll will need to be carefully performed with attend paid to

• Contusions/abrasions/haematomas
• Areas of pain, bogginess or palpable crepitations/steps
• PR exam (as part of the ASIA exam – checking for anal tone and the perception of deep anal pressure)

Other neurological findings that may be useful include

• Priapism in males – if present generally indicates a complete SCI (note not all men with complete SCIs will develop this)
• The bulbocavernosus reflex (anal contraction resulting from squeezing of the glans penis or tugging on foley catheter) can be performed to give more prognostic information.
  • Recovery of the bulbocavernosus reflex is an indication of recovery from spinal shock. However, if the bulbocavernosus reflex returns with ongoing absent power and sensation this indicates a complete cord injury.

Investigations

Standard trauma bloods

Arterial blood gas measurements are important in patients with higher level SCI as the development of hypercapnoea can indicate impending respiratory failure.

Imaging

Plain films as part of an initial trauma assessment have a limited role in patients with neurological deficits from suspected SCI. CT is the imaging modality of choice. CT also has the advantage of detecting other injuries (eg: intraabdominal injuries).

10-15% of patients with a SCI will have a non-contiguous spinal fracture so the entire spine should be imaged if a significant # is found, preferably with CT.

MRI will usually be required to further characterise the cord itself and the surround soft tissues (ligaments, discs, paraspinal soft tissues) as well as detect epidural haematomas.

MRI is also invaluable in the workup of SCIWORA (spinal cord injury without radiological abnormality – ie: no boney abnormality on CT) as it will generally detect spinal cord injuries if present.

 

Definitive management

Decisions regarding definitive management (reduction of cervical dislocations or operative interventions) will be led by the spinal surgeons.

Patients with cervical spine fractures with subluxation will usually require reduction via traction techniques. Skull tongs or a halo are applied to the head with incrementally increasing weighted traction applied (note this is strictly led by the spinal surgeons)

Indications for operative management include

• Fractures or dislocations with retropulsed fragments into the spinal canal
  • Urgent decompression might be required, and may improve function
• Unstable fractures (generally 2 or more columns)

 

Supportive care

Analgesia

Judicious use of titrated opiates (eg: fentanyl) will be required to treat pain. Even though fentanyl is relatively cardiovascularly sparing, care should be taken to avoid worsening shock. Patients with the potential for respiratory failure will also need to be treated carefully with any opiates.

Antiemetic

As the patient will be immobilised (from strict spinal cares and potentially paralysis) it is prudent to treat prophylactically with ondansetron.

Nasogastric tube

Early placement of an NG tube is important as these patients are at high risk of ileus and aspiration

IDC

Place early

Prevent hypothermia

Patient with SCI can develop a polikotherm state due to vasodilation leading to increased heat loss. Keep the patient covered with blankets, avoid draughts/fans etc.

Pressure cares

Pressure areas can develop remarkably rapidly in paralysed patients. Backboards should be removed on arrival to the ED if they have been placed prehospital. Hard cervical spine collars should be replaced with Aspen or other similar softer collars as soon as practical (though these still need to be watched carefully for pressure areas around especially around the pinna, chin, occiput and manubrium. Attention to the skin around the heels and buttocks is also essential. Patients should have spinal rolls q2h.

Steroids

Steroids are NOT currently used in the treatment of acute SCI in New Zealand.

The use of steroids in patients with SCI has been an area of significant controversy.⁵ There is some evidence that administration within 8 hours might result in a modest improvement in motor function. However, this benefit is probably marginal at best, and is counterbalanced by the increased risk of infections/sepsis and GI bleeding associated with steroid use in trauma patients.

Psychosocial

Patients with SCI and their families will likely be extremely anxious about the injury and their long term prognosis. The physical examination combined with imaging will give an indication regarding potential for recovery – early frank discussions regarding expectations should take place. Involvement of social work and cultural support is important.

ICU/ward issues

• Ongoing attention to pressure areas
• DVT prophylaxis
• Gastric ulcer prophylaxis
• Bowel cares
• Ongoing psychosocial support

 

Disposition – interhospital destination guidelines

SCI other injuries

 

Destination SCI with motor

 

Destination no motor

 

References

1. New Zealand Spinal Cord Impairment Action Plan 2014–2019
   http://www.health.govt.nz/publication/new-zealand-spinal-cord-impairment-action-plan-2014-2019
2. Walters BC, Hadley MN, Hurlbert RJ, Aarabi B, Dhall SS, Gelb DE, Harrigan MR, Rozelle CJ, Ryken TC, Theodore N. Guidelines for the management of acute cervical spine and spinal cord injuries: 2013 update. Neurosurgery. 2013 Aug 1;60(CN_suppl_1):82-91.
3. Readdy WJ, Dhall SS. Vasopressor administration in spinal cord injury: should we apply a universal standard to all injury patterns?. Neural regeneration research. 2016 Mar;11(3):420.
4. Martin ND, Kepler C, Zubair M, Sayadipour A, Cohen M, Weinstein M. Increased mean arterial pressure goals after spinal cord injury and functional outcome. Journal of emergencies, trauma, and shock. 2015 Apr;8(2):94.
5. Bracken MB. Steroids for acute spinal cord injury. The Cochrane Library. 2012 Jan 18.
   https://www.cns.org/guidelines/guidelines-management-acute-cervical-spine-and-spinal-cord-injuries