Spinal cord injury

What is a spinal cord injury?

The spinal cord extends from the base of the skull and terminates near the lower margin of the L1 vertebral body. Below L1, the spinal canal contains the lumbar, sacral and coccygeal spinal nerves that comprise the cauda equina. Therefore, injuries below L1 involve the segmental spinal nerves and/or cauda equina. Injuries above the termination of the spinal cord at L1 often involve both spinal cord lesions and segmental root or spinal nerve injuries.

Spinal cord injuries may be primary or secondary:^{1 2}

• Primary injuries arise from a variety of mechanisms, including mechanical disruption, transection, penetrating injuries due to bullets or weapons, vertebral fracture/subluxation or displaced bony fragments causing penetrating spinal cord and/or segmental spinal nerve injuries.

• The primary traumatic impact initiates vascular and chemical processes leading to oedema and ischaemia which can lead to secondary injuries.

• Further cord insult can occur through subsequent inappropriate manual handling following trauma.

• Secondary injuries are mostly caused by arterial disruption, thrombosis or hypoperfusion due to shock.

Most injuries to the spinal cord don't completely sever it. An injury is more likely to cause fractures and compression of the vertebrae, which then crush and destroy the spinal nerve tracts. The prognosis is variable between almost complete recovery and complete paralysis.

Spinal cord injuries may be either complete or incomplete.¹ An incomplete injury means that the ability of the spinal cord to convey messages to or from the brain is not completely lost. People with incomplete injuries retain some motor or sensory function below the injury. A complete injury is indicated by a total lack of sensory and motor function below the level of injury.

How common is a spinal cord injury? (Epidemiology)³

• The incidence of traumatic spinal cord injury in Western Europe is about 16 per million.⁴ Spinal cord injury in children is relatively rare.⁵

• Approximately 1,000 people sustain a new spinal cord injury each year in the UK.

• A traumatic spinal cord injury is a lesion of neural elements of the spinal cord that can result in any degree of sensory and motor deficit, and autonomic or bowel dysfunction.⁶

• The main causes of spinal injury are road traffic collisions, falls, violent attacks, sporting injuries and domestic incidents.

• Although spinal injury affects all ages, young and middle-aged men and older women tend to be the populations at highest risk.

• Despite the cervical spine being injured in only 3% of blunt trauma victims, the results can be catastrophic due to spinal cord injury. The subaxial cervical spine is a common site of cervical injury with more than 50% of injuries being located between C5 and C7.⁷

Risk factors for spinal injury

• Major trauma - eg, motor vehicle accidents, violent assaults, gunshot wounds, falls, sports and recreation injuries.

• Suggestive mechanism of injury.

• Spinal pain or neurological symptoms/signs.

• Altered consciousness.

• Increased risk in patients with malignancy, inflammation of the spinal cord, osteoporosis, rheumatoid arthritis, osteoarthritis, ankylosing spondylitis, Down's syndrome and in the elderly.

Presentation of spinal cord injury

See separate Examination of the Spine, Neurological History and Examination, Neurological Examination of the Upper Limbs and Neurological Examination of the Lower Limbs articles.

The most common issues raised by people with spinal cord injury in primary care are related to disability and secondary complications such as bowel or bladder dysfunction and pain.⁸

Motor, sensory and autonomic dysfunction can occur. The latter can lead to neurogenic shock, paralytic ileus, aspiration, urinary retention, priapism and loss of thermoregulation. Clinical features depend upon the extent and rate of development of cord compression.

• Motor symptoms can include ready fatigue and disturbance of gait.

• Cervical spine lesions can produce quadriplegia. Injury above the level of C3, C4, C5 (the segmental level of the phrenic nerve) causes paralysis of the diaphragm and artificial ventilation is required.

• Thoracic spine lesions produce paraplegia.

• Lumbar spine lesions can affect L4, L5 and sacral nerve roots.

• Sensory symptoms can include sensory loss and paraesthesia. Light touch, proprioception and joint position sense are reduced.

• There can be root pain in the legs.

• Tendon reflexes are typically:
  

  • Increased below the level of injury and/or compression.

  • Absent at the level of injury and/or compression.

  • Normal above the level of injury and/or compression.

• Sphincter disturbances - late features of cervical and thoracic cord and/or compression.

• There may be loss of autonomic activity with lack of sweating below the level, loss of thermoregulation and drop in peripheral resistance causing hypotension.

Patterns of injury

• Complete cord injury:

  • Absence of any motor or sensory function below the level of the injury.

  • Minimal chance of functional recovery.

• Anterior cord syndrome:

  • This is caused by direct anterior cord compression, flexion injuries of the cervical spine, or thrombosis of anterior spinal artery.

  • Leads to variable paralysis below the lesion level with loss of pain and temperature perception.

  • Dorsal columns (proprioception and vibration sense) are mainly preserved.

  • Has a poor prognosis.

• Brown-Séquard's syndrome:

  • Caused by hemi-transection or unilateral compression of the cord.

  • Ipsilateral spastic paresis and loss of proprioception and vibration sense.

  • Contralateral loss of pain and temperature perception.

  • Moderately good prognosis.

• Central cord syndrome:
  

  • Caused by hyperextension injuries, spinal cord ischaemia and cervical spinal stenosis.

  • Usually involves a cervical lesion, with greater motor weakness in the upper extremities than in the lower extremities.

  • The pattern of motor weakness shows greater distal involvement in the affected extremity than proximal muscle weakness.

  • Sensory loss is variable, with pain and/or temperature sensation more likely to be affected than proprioception and/or vibration.

  • Burning sensation, especially in the upper extremities, is common.

  • There is usually sacral sensory sparing.

• Posterior cord syndrome:
  

  • Very rarely occurs in isolation.

  • Caused by penetrating trauma to the back or hyperextension injury associated with vertebral arch fractures.

  • Loss of proprioception and vibration sense.

  • Motor and pain/temperature sensation preserved.

• Spinal cord concussion:
  

  • Rare.

  • Temporary cessation of spinal cord neurological function; however, spontaneous recovery occurs within 48 hours.

• Spinal shock:
  

  • Immediate flaccidity, paralysis, areflexia and loss of sensation below the level of the acute spinal cord injury.

  • Some reflexes return after a few days and hyperreflexia typical of an upper motor neurone lesion in weeks.

• Neurogenic shock:
  

  • Distributive shock from sympathetic fibre disruption causes vasodilatation and hypotension.

  • Occurs with high thoracic, cervical spine, and profound brain injuries (spinal cord injury above T6).

  • The triad of hypotension, relative bradycardia, and hypothermia is characteristic.

  • Areflexia, loss of sensation and flaccid paralysis below the level of the lesion; flaccid bladder and loss of rectal tone.

• Spinal cord injury without radiological abnormality (SCIWORA):⁹
  

  • SCIWORA is a syndrome occurring when the spinal cord sustains neural damage during a traumatic event without positive radiology findings.

  • This can be diagnosed only after scans have shown no bony or ligamentous injury.

  • It is more common in children (as their spine is more flexible and less likely to sustain vertebral fracture) and carries a poor prognosis.

Assessment³

Assessing children with suspected thoracic or lumbosacral spine injury is difficult and the child's developmental stage should be taken into account.

Assess the person for spinal injury

Check if the person:

• Has any significant distracting injuries.

• Is under the influence of drugs or alcohol.

• Is confused or unco-operative, or has a reduced level of consciousness.

• Has any spinal pain.

• Has any hand or foot weakness (motor assessment).

• Has altered or absent sensation in the hands or feet (sensory assessment).

• Has priapism (unconscious or exposed male).

• Has a history of past spinal problems, including previous spinal surgery or conditions that predispose to instability of the spine.

Assessment for cervical spine injury

Assess whether the person is at high, low or no risk for cervical spine injury using the Canadian C-spine rule as follows:

The person is at high risk if they have at least one of the following high-risk factors:

• Age 65 years or older.

• Dangerous mechanism of injury (fall from a height of greater than 1 metre or five steps, axial load to the head - eg, diving, high-speed motor vehicle collision, rollover motor accident, ejection from a motor vehicle, accident involving motorised recreational vehicles, bicycle collision, horse riding accidents).

• Paraesthesia in the upper or lower limbs.

• The person is at low risk if they have at least one of the following low-risk factors:

  • Involved in a minor rear-end motor vehicle collision.

  • Comfortable in a sitting position.

  • Ambulatory at any time since the injury.

  • No midline cervical spine tenderness.

  • Delayed onset of neck pain.

The person remains at low risk if they are unable actively to rotate their neck 45° to the left and right (the range of the neck can only be assessed safely if the person is at low risk and there are no high-risk factors). The person has no risk if they have one of the above low-risk factors and are able actively to rotate their neck 45° to the left and right.

Assessment for thoracic or lumbosacral spine injury

Assess the person with suspected thoracic or lumbosacral spine injury using these factors:

• Age 65 years or older and reported pain in the thoracic or lumbosacral spine.

• Dangerous mechanism of injury (fall from a height of greater than 3 metres, axial load to the head or base of the spine - eg, falls landing on feet or buttocks, high-speed motor vehicle collision, rollover motor accident, lap belt restraint only, ejection from a motor vehicle, accident involving motorised recreational vehicles, bicycle collision, horse riding accidents).

• Pre-existing spinal pathology, or known or at risk of osteoporosis - eg, steroid use.

• Suspected spinal fracture in another region of the spine.

• Abnormal neurological symptoms (paraesthesia or weakness or numbness).

• Examination findings: abnormal neurological signs (motor or sensory deficit), new deformity or bony midline tenderness (on palpation), bony midline tenderness (on percussion), or midline or spinal pain (on coughing).

• On mobilisation (sit, stand, step, assess walking): pain or abnormal neurological symptoms (stop if this occurs).

Investigations¹⁰

• Haemoglobin and haematocrit levels should be measured initially and monitored serially to monitor blood loss.

• Renal function and electrolytes: dehydration.

• Perform urinalysis to detect associated genitourinary injury.

• X-rays:

  • Diagnostic imaging begins with X-rays of the affected region of the spine. In some centres, CT scanning has supplanted plain X-rays.

  • A trauma X-ray series is usually first performed (cervical spine, chest and pelvis).¹¹

• CT scan may pick up fractures missed on plain radiographs and is the preferred first radiological investigation in some centres.

• If a patient is unconscious then CT of the brain and the whole of the cervical spine has now become routine.¹¹

• X-rays of the cervical spine are indicated in any patient following a head and/or facial injury unless all the following criteria are met:¹²
  

  • No midline cervical tenderness.

  • No focal neurological deficit.

  • Normal alertness.

  • No intoxication.

  • No painful, distracting injury.

• The standard three views of the cervical spine are recommended: anteroposterior, lateral and odontoid.

• X-rays of the thoracic and lumbar spine are indicated in any patient with pain or tenderness, a significant fall, a high-impact road traffic accident, presence of other spinal fracture and when it is not possible to evaluate the patient clinically. Anteroposterior and lateral views of the thoracic and lumbar spine are recommended. Radiographs must adequately depict all vertebrae.

• CT scan:

  • Plain X-rays are insensitive to small vertebral fractures. In general, CT should be the first-line approach in high-risk patients and plain X-rays should be reserved for the initial evaluation of patients with a low risk of traumatic lesions.¹³

  • CT scanning is reserved for delineating bony abnormalities or fracture. Some studies have suggested that CT scanning with sagittal and coronal reformatting is more sensitive than plain X-rays for the detection of spinal fractures.

  • Perform CT scanning in the following situations:
    

    • Plain radiography is inadequate.

    • Convenience and speed: for example, if a CT scan of the head is required then it may be simpler and faster to obtain a CT of the cervical spine at the same time.

    • X-rays show suspicious and/or indeterminate abnormalities.

    • X-rays show fracture or displacement: CT scanning provides better visualisation of the extent and displacement of the fracture.

  • CT/MRI of the thoracic and lumbar spine is essential for any patient who has a neurological deficit following trauma.

• MRI:

  • MRI has been playing an increasingly important role in spinal trauma patients due to high sensitivity for detection of acute soft tissue and cord injuries.¹⁴

  • If the lateral cervical radiograph and the CT scan are negative, then MRI is the investigation of choice to exclude instability.

  • However, in a blunt trauma adult patient with altered sensation, a normal cervical spine CT scan is considered conclusive to safely rule out a clinically significant cervical spine injury.¹⁵

  • However, spinal cord injury in children frequently occurs without fracture or dislocation (see SCIWORA above).⁹

  • Patients with focal neurological signs, evidence of cord or disc injury, and patients whose surgery requires pre-operative cord assessment, should also have an MRI scan.¹¹

  • Whole spine MRI is indicated for multilevel or ligamentous injuries and for cauda equina injuries.

  • MRI is best for suspected spinal cord lesions, cord compressions, vertebral fractures at multiple levels and ligamentous injuries or other soft tissue injuries or pathology.

  • MRI should be used to evaluate soft tissue lesions, such as extradural spinal haematoma, abscess or tumour, or spinal cord haemorrhage, contusion and/or oedema.

  • Neurological deterioration is usually caused by secondary injury, resulting in oedema and/or haemorrhage. MRI is the best diagnostic image to depict these changes.

• CT myelography may be considered if MRI is not practicable.

Initial management of a spinal cord injury^{16 10}

• Maintaining stability of the spine and immediate referral to the appropriate local severe trauma service are essential for patients with a possible cervical spine fracture.

• Resuscitation: initial resuscitation following the standard ABCDE protocol, with assessment and management of airway, respiration and circulation as the first priority.

• Stabilise and immobilise the spine:
  

  • At all stages of the assessment, protect the cervical spine with manual in-line spinal immobilisation, particularly during any airway intervention, and avoid moving the remainder of the spine.

  • The patient should be transported immobilised on a spinal board and with a cervical hard collar to maintain spinal alignment.

  • The patient should be secured so that in the event of vomiting, the spinal board may be rapidly rotated while the patient remains fully immobilised in the neutral position.

  • The patient is best treated initially in the supine position.

  • Logrolling the patient to the supine position is safe to facilitate diagnostic evaluation and treatment.

  • Use analgesics (these should initially be given intravenously) to maintain the patient's comfort, especially if they have been lying on a hard backboard for an extended period.

• Airway management:
  

  • In patients with spinal cord injuries, with or without a cervical spine injury, airway management is often difficult.

  • All airway interventions cause spinal movement; immobilisation may have a modest effect in limiting spinal movement during airway manoeuvre.¹⁷

  • The cervical spine must be maintained in a neutral alignment at all times.

  • Clearing of oral secretions and debris is essential to maintain a patent airway and to prevent aspiration.

  • The modified jaw thrust and insertion of an oral airway may be all that is required to maintain an airway in some cases. However, intubation may be required in others.

  • The ideal technique for emergency intubation is fibre-optic intubation with cervical spine control.

  • Indications for intubation in patients with spinal cord injury are acute respiratory failure, decreased level of consciousness (Glasgow score <9), increased respiratory rate with hypoxia, PCO₂ more than 50 mm Hg, and vital capacity less than 10 mL/kg. If a lesion is present at or above C5, intubation and assisted ventilation will often be required.

• Breathing:
  

  • Give oxygen (hypoxia can compromise the injured cord).

  • Watch for paradoxical (diaphragmatic) breathing indicating a possible cervical injury.

• Hypotension:
  

  • May be due to haemorrhage or neurogenic shock in acute spinal cord injuries.

  • Haemorrhage may be due to other injuries - eg, chest, intra-abdominal, retroperitoneal, or pelvic or long bone fractures.

  • Initial treatment of spinal shock is careful fluid replacement, usually with an isotonic crystalloid solution.

• Haemodynamically significant bradycardia should be treated with atropine (pharyngeal stimulation - eg, oral suctioning - can also induce significant bradycardia).

• For people with spinal injury use intravenous morphine as the first-line analgesic and adjust the dose as needed to achieve adequate pain relief.³

• A urinary catheter should be inserted and the urine output monitored. Occasionally, a positive inotrope such as dopamine is required.

• Associated head injury: may require assessment with CT scan and appropriate management.

• Ileus is common. A nasogastric tube is essential. Anti-emetics should be used to prevent aspiration.

• Prevent pressure sores: regular turning of the patient, protective padding to all extensor surfaces and removal of the spinal board as soon as safe and appropriate.

• High-dose methylprednisolone steroid therapy is the only pharmacological treatment shown to be effective when given within eight hours of injury.¹⁸ However, the use of methylprednisolone remains controversial and only considered of marginal benefit.¹⁹

• Treatment of pulmonary complications and/or injury in patients includes oxygen for all patients and appropriate treatment for pneumothorax and/or haemothorax.

• Further assessment and monitoring:
  

  • ECG monitoring.

  • Monitor Glasgow Coma Scale.

  • Temperature: there may be loss of thermoregulation, so keep the patient comfortably warm.

  • A thorough but rapid assessment of all major injuries is essential. Head to toe examination for other injuries, especially neurological and skeletal.

  • Full neurological examination of motor and sensory functions.

Extrication³

• When there is immediate threat to a person's life and rapid extrication is needed, make all efforts to limit spinal movement without delaying treatment.

• Consider asking a person to self-extricate if they are not physically trapped and have none of the following:

  • Significant distracting injuries.

  • Abnormal neurological symptoms (paraesthesia or weakness or numbness).

  • Spinal pain.

  • High-risk factors for cervical spine injury as assessed by the Canadian C-spine rule.

• Explain to a person who is self-extricating that if they develop any spinal pain, numbness, tingling or weakness, they should stop moving and wait to be moved.

• When a person has self-extricated, ask them to lie supine on a stretcher positioned adjacent to the vehicle or incident in the ambulance; assess them for spinal injury and manage their condition.

• People with suspected spinal injury should not be transported on a longboard or any other extrication device. A longboard should only be used as an extrication
  device.

Further management of a spinal cord injury^{16 20 21}

• Immediate referral to a neurosurgeon and any other specialties, depending on the nature of the injuries, especially an orthopaedic trauma specialist and general surgeon. Once stabilised, patients should be referred to a regional spinal cord injuries centre.

• Emergency decompression of the spinal cord is recommended for patients with extradural lesions, such as epidural haematomas. Impingement of spinal nerves or acute neurological deterioration requires emergency surgical intervention.

• An interdisciplinary approach is essential in rehabilitation. The team will include the patient's family, physiotherapist, occupational therapist, dietician, psychologist, speech therapist, social worker and other consultant specialists as necessary.

• Spasticity following spinal cord injury: one review found a significant effect of tizanidine but not gabapentin, clonidine, diazepam or oral baclofen.²²

• Respiratory muscle training is effective for increasing respiratory muscle strength and perhaps also lung volumes for people with cervical spinal cord injury.²³

Complications of spinal cord injuries¹⁶

• Spinal injuries are associated with serious neurological damage and can result in paraplegia, tetraplegia or death.³ The neurological deficit often increases during the first few days following acute spinal cord injury. One of the first signs of deterioration is the cephalic extension of the sensory deficit.

• Autonomic dysreflexia: associated with spinal cord injury at or above T6. If not treated promptly and correctly, it may lead to seizures, stroke and even death. Features include:
  

  • Acute, uncontrolled hypertension.

  • Severe headache.

  • Intense sweating and skin blotches above the level of the injury.

  • Cold and clammy skin below the level of the injury.

  • Restlessness.

  • Chest tightness.

  • Bradycardia.

  • Dilated pupils.

• Pressure sores: careful and frequent turning of the patient is essential.

• Hypothermia.

• Potential lung complications include aspiration, pneumonia, acute respiratory distress syndrome, atelectasis, ventilation-perfusion mismatch and decreased coughing with retention of secretions.

• Chronic musculoskeletal pain is common in people with spinal cord injury.²⁴

• Depression can occur and those with spinal cord injury have an increased risk of suicide.

• Leading causes of death after spinal cord injury include pneumonia, pulmonary emboli, septicaemia and acute kidney injury.

Prognosis¹⁶

• The spinal cord has very limited powers of regeneration. Patients with a complete cord injury have a very low chance of recovery, especially if paralysis persists for longer than 72 hours. The prognosis is much better for the incomplete cord syndromes.

• The prognosis for cervical spine fractures and dislocations is very variable, depending on the degree of neurological disability.

• Prognosis for neurological deficit depends on the magnitude of the spinal cord damage present at the onset.

• As well as neurological dysfunction, the prognosis is also determined by the prevention and effective treatment of infections - eg, pneumonia, and urinary tract infections.

• In general, most individuals regain some motor function, mostly within the first six months, although there may be further improvement observed years later.

• People who survive a spinal cord injury often have medical complications - eg, chronic pain, bladder and bowel dysfunction, and increased susceptibility to lower respiratory tract infections.

Prevention

• Avoidance of excess alcohol intake.

• Road safety.

• Encourage adherence to rules and safety regulations with high-risk activities - eg, rugby, equestrian pursuits, hang-gliding.