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:

• Primary injuries arise from e.g. mechanical disruption, transection, penetrating injuries due to bullets or weapons, or displaced bony fragments cause penetrating spinal cord and/or segmental spinal nerve injuries.
• Secondary injuries are mostly caused by arterial disruption or thrombosis, or hypoperfusion due to shock.

A spinal cord injury usually begins with a sudden, traumatic blow to the spine that fractures or dislocates vertebrae. The damage begins at the moment of injury when displaced bone fragments, disc material, or ligaments bruise or tear into spinal cord tissue. Most injuries to the spinal cord don't completely sever it. Instead, 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 are classified as either complete or incomplete. 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.

The initial cord insult can be caused by vertebral fracture/subluxation, blunt trauma or direct penetrating trauma. Further cord insult can occur through subsequent inappropriate manual handling. The prime directive is always to consider the possibility of spinal injury, especially if:

• Major trauma
• Suggestive mechanism of injury
• Spinal pain or neurological symptoms/signs
• Altered consciousness
• Risk factors for spine injury, e.g. osteoporosis, rheumatoid arthritis, ankylosing spondylitis, Down's syndrome and the elderly.

Cervical spine injury involves trauma to bony or ligamentous structures of the cervical spine, with or without spinal cord damage. Whiplash associated disorder (WAD) is used to describe damage to the soft tissues of the neck caused by an acceleration/deceleration mechanism. The commonest causes of cervical spine injuries are road traffic accidents, falls and sports injuries (e.g. diving, rugby, gymnastics, skiing, hang gliding, equestrian). The majority of patients with serious cervical spine injury are between 18 and 25 years old.

Approximately 5-10% of unconscious patients who have been involved in a motor vehicle accident or fall have a major injury to the cervical spine. Most cervical spine fractures occur predominantly at 2 levels:¹

• One third of injuries occur at the level of C2, and one half of injuries occur at the level of C6 or C7.
• Most fatal cervical spine injuries occur in upper cervical levels, either at craniocervical junction C1, or at C2.

The most common causes of spinal cord injury are:

• Motor vehicle accidents
• Violent assaults, gunshot wounds
• Falls
• Sports and recreation injuries
• Malignancy, infections, arthritis and inflammation of the spinal cord also cause spinal cord injuries.

• The primary traumatic impact initiates vascular and chemical processes leading to oedema and ischaemia which can lead to secondary injuries.
• Motor, sensory and autonomic dysfunction can occur. The latter can lead to neurogenic shock, paralytic ileus, aspiration, urinary retention, priapism, and loss of thermoregulation.

Patterns of injury

• Complete cord injury
  • Absence of any motor or sensory function below the level of the injury
  • Minimal chance of functional recovery
  • Incomplete cord injury
• Anterior cord syndrome
  • Caused by direct anterior cord compression, flexion injuries of cervical spine, or thrombosis of anterior spinal artery.
  • Leads to variable paralysis below lesion level with loss of pain and temperature perception.
  • Dorsal columns (proprioception and vibration sense) are mainly preserved.
  • Poor prognosis.
• Brown-Séquard syndrome
  • Caused by hemi-transection or unilateral compression of the cord.
  • Ipsilateral spastic paresis and loss of proprioception & 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, but spontaneous recovery occurs within 48 hours.
• Spinal shock
  • Spinal shock results from autonomic dysfunction and the interruption of sympathetic nervous system control in acute spinal cord injuries.
  • Spinal shock is characterized by severe autonomic dysfunction, resulting in hypotension, relative bradycardia, peripheral vasodilation, and hypothermia.
  • It occurs with spinal cord injuries above T6 but does not usually occur with injuries below the level of T6 (hypotension and/or shock with acute spinal cord injury at or below T6 is usually caused by haemorrhage).
  • Areflexia, loss of sensation, and flaccid paralysis below the level of the lesion; flaccid bladder and loss of rectal tone; bradycardia and hypotension.
• SCIWORA (Spinal Cord Injury Without Radiological Abnormality)
  • This can be diagnosed only after scans have shown no bony or ligamentous injury.
  • More common in children (as their spine is more flexible and less likely to sustain vertebral fracture) and carries a poor prognosis.

• Spinal epidural haematomas and abscesses may cause acute cord compression.
• Spinal cord compression from metastatic disease
• Aortic artery dissection
• Epidural and subdural Infections
• Syphilis
• Transverse myelitis
• Acute intervertebral disk herniation

• 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-rays²
  • 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).³ 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.³
  • 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:
    • No midline cervical tenderness
    • No focal neurological deficit
    • Normal alertness
    • No intoxication
    • No painful, distracting injury
  • The standard 3 views of the cervical spine are recommended: anteroposterior, lateral, and odontoid.
  • X-rays of 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 clinically evaluate the patient. Anteroposterior and lateral views of the thoracic and lumbar spine are recommended. Radiographs must adequately depict all vertebrae.
• CT scan²
  • Plain x-rays are insensitive to small fractures of the vertebra. 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.⁴
  • 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: e.g. 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 visualization 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.
• MRI²
  • If the lateral cervical radiograph and the CT scan are negative, then MRI is the investigation of choice to exclude instability.
  • Patients with focal neurological signs, evidence of cord or disc injury, and patients whose surgery require pre-operative cord assessment should also have an MRI scan.³
  • 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.

• Maintaining stability of the spine and immediate referral to the appropriate local severe trauma service is 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 is the first priority.
• Stabilize and immobilize 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 immobilized 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 (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, is often difficult. All airway interventions cause spinal movement; immobilization may have a modest effect in limiting spinal movement during airway manoeuvre.⁵ 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 50mmHg, 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 neurological (spinal shock) in acute spinal cord injuries. Haemorrhage may be due to other injuries, e.g. 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, e.g. oral suctioning, can also induce significant bradycardia).
• 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. Antiemetics should be used to prevent aspiration.
• Prevent pressure sores: regular turning of the patient, protective padding to all extensor surfaces and remove the spine board as soon as safe and appropriate.
• High-dose intravenous methylprednisolone is the only drug shown to have benefit when administered within eight hours of acute spinal cord injury. There may be an additional benefit by extending the maintenance dose from 24 to 48 hours, if start of treatment is delayed to between three and eight hours after injury.⁶
• 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 exam for other injuries especially neurological and skeletal.
  • Full neurological examination of motor and sensory functions.

• Immediate referral to a neurosurgeon and any other specialties depending on the nature of the injuries, especially orthopaedic trauma specialist and general surgeon. Once stabilized, 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. Emergency surgical decompression is recommended in specific injuries such as facet dislocation, bilateral locked facets, or cauda equina syndrome.⁷
• However the role of immediate surgical intervention is otherwise limited.⁷
• Medium and long term management is directed towards rehabilitation, including physiotherapy and occupational therapy.

• 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.
• 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.

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

• Avoidance of excess alcohol intake
• Road safety
• Encourage adherence to rules and safety regulations with high-risk activities (e.g. rugby, equestrian, hang gliding).