Primary spinal cord injury

• The immediate trauma that results in the contusion, compression, low blood flow state, distraction, transection, or laceration of the spinal cord.
  
• Penetrating injuries can result in a complete or partial spinal cord transection.
  
  
  
  • Gunshot wounds may injure the spinal cord via the transferred kinetic energy, in addition to the direct missile injury.
    
  • Knife wounds usually create a more defined trajectory of injury.
  
  
• Blunt injuries, such as motor vehicle collisions, can result in more variable levels and severities of injury.

Secondary spinal cord injury

• Following the immediate trauma, secondary injury can occur to the spinal cord within minutes to hours.
  
• Mechanisms of secondary injury to the spinal cord include
  
  
  
  • Hypoxia
    
  • Ischemia
    
  • Inflammation
    
  • Edema
    
  • Necrosis
    
  • Electrolyte and ion disturbances
    
  • Excitotoxicity and apoptosis.
  
  
• Following a spinal cord injury, all efforts should be made to minimize any secondary injury to the spinal cord, which can result in progression of neurological deterioration.

Clinical presentations and grading systems

• Universal spinal immobilization after significant trauma continues to be an important practice. All patients are assumed to have TSCI until safely demonstrated otherwise.
  
• Physicians should have a high level of suspicion of TSCI in patients who present with multiple injuries, patients with head injuries, and those who are unconscious.
  
• Patients with spinal vertebrae fractures may complain of pain at the site of injury. However, head or associated injuries may limit a patient’s ability to reliably identify TSCIs.
  
• American Spinal Injury Association (ASIA) Scale
  
  
  
  • Complete spinal cord injury
    
    
    
    • A complete spinal cord injury patient is given an ASIA Scale A.
      
    • Patients with a complete spinal cord injury will present with:
      
      
      
      • Sensation spared above the level of injury
        
      • Reduced muscle strength and tone below the level of injury; flaccid muscle tone more caudally
        
      • Reduced or absent reflexes
        
      • Priapism
        
      • Absent bulbocavernous reflex
        
      • Urinary retention, bladder distension.
    
    
  • Incomplete spinal cord injury
    
    
    
    • Incomplete spinal cord injuries are given ASIA Scale scores of B through E, depending on the severity of the injury and the extent of neurological dysfunction.
      
    • These patients would present with varying degrees of motor function.
      
    • Sensation is often spared more than motor function.
      
    • The bulbocavernous reflex and anal sensation are present.
      
      
      
      • The importance of the rectal examination in a trauma patient is to characterize the severity of TSCI and the patient’s prognosis of neurological recovery.
  
  
• Incomplete traumatic spinal cord injury syndromes
  
  
  
  • These patients present with incomplete spinal cord injuries, and would be classified as ASIA Scale B through E.
    
  • Central cord syndrome
    
    
    
    • Motor function deficits are greater in the upper extremities, as opposed to the lower extremities.
      
    • There is a variable loss of sensation below the level of injury
      
    • There may be associated bladder dysfunction
      
    • Most common in elderly patients with underlying cervical canal narrowing after hyperextension injury.
    
    
  • Anterior cord syndrome
    
    
    
    • Occurs after injury to the anterior two-thirds of the spinal cord.
      
    • May occur after direct trauma to the anterior spinal artery.
      
    • More commonly is due to bony fragments or intervertebral disk impingement on the spinal artery.
      
    • Spares the dorsal column; intact light touch and proprioception.
    
    
  • Brown–Séquard syndrome
    
    
    
    • Often secondary to a spinal cord transection.
      
    • Loss of motor function ipsilateral to the side of the injury.
      
    • Loss of pain, temperature, and sensation contralateral to the injured side.
    
    
  • Cauda equina syndrome
    
    
    
    • Decreased anal tone causing fecal incontinence
      
    • Saddle anesthesia
      
    • Lower extremity pain or weakness
      
    • Decreased or absent ankle reflexes
      
    • Sphincter weakness resulting in urinary retention and postvoid residual incontinence.
  
  
• Clinical examination findings
  
  
  
  • Neurogenic shock
    
    
    
    • Life threatening; true shock state.
      
    • Inadequate perfusion resulting from spinal cord injury.
      
    • Decreased vascular resistance due to interrupted autonomic pathways.
      
    • Presents with:
      
      
      
      • Hypotension
        
      • Bradycardia
        
      • Decreased cardiac output
        
      • Warm, dry extremities
        
      • Peripheral vasodilation
        
      • Temperature dysregulation.
    
    
  • Spinal shock
    
    
    
    • Not a true shock state.
      
    • A transient phenomenon lasting minutes to hours.
      
    • Temporary loss of sensation, motor paralysis, and diminished reflexes.
      
    • Often results from complete transection.
      
    • There is no cardiovascular compromise.
    
    
  • Autonomic dysreflexia
    
    
    
    • Due to a significant sympathetic discharge from afferent stimuli below the level of injury.
      
    • Presents with:
      
      
      
      • Hypertension
        
      • Bradycardia
        
      • Sweating, flushing.

Initial evaluation

• Follow the Trauma Assessment Algorithm, as outlined in the Advanced Trauma Life Support (ATLS) course, and discussed in other sections of this manual.
  
• Always remember to protect the cervical spine (c-spine) in all trauma patients with a rigid collar, especially those with head injuries, multiple injuries, neurological deficits, or in those who are unconscious.
  
• Immobilize the spine during transportation with a rigid long board. During the hospital assessment, remove the long board by log-rolling the patient until spinal injuries have been excluded.
  
• Consider and evaluate for any life-threatening injuries associated with the trauma.
  
  
  
  • The evaluation and treatment of life-threatening injuries, such as significant hemorrhage, pneumothorax, or airway compromise, take precedence over spinal cord injuries. Such injuries can lead to secondary spinal cord trauma, and therefore should be treated quickly to minimize further neurological deterioration.
  
  
• Airway and breathing
  
  
  
  • One-third of all patients with cervical spine injuries will require intubation within the first 24 hours.
    
  • Hypoxia can lead to secondary spinal cord injury, and should be quickly corrected.
    
  • Monitor the patient with pulse oximetry and use supplemental oxygen as needed.
  
  
• Circulation
  
  
  
  • Hypotension in a trauma patient should be assumed to be due to hemorrhagic shock until proven otherwise.
    
  • Hypotension can also be due to neurogenic shock.
    
  • Spinal shock does not result in hypotension.
  
  
• Neurological examination
  
  
  
  • A complete examination should be conducted to determine the level and severity of injury.
    
  • A mental status examination should be conducted, including an initial Glasgow Coma Scale (GCS), as explained in other sections of this manual.
    
  • Cranial nerve examination should be conducted, if possible, as many TSCI patients also sustain significant head trauma.
  
  
• Imaging of spinal cord injuries
  
  
  
  • National Emergency X-Radiography Utilization Study (NEXUS)
    
    
    
    • Allows the clinical clearance of c-spine injuries (no radiography).
      
    • NEXUS criteria for clinical c-spine clearance:
      
      
      
      • Alert, with no confusion
        
      • No distracting injuries
        
      • Not intoxicated
        
      • No neurological deficits
        
      • No midline c-spine pain or tenderness.
      
      
    • These five criteria for clinical clearance had a 99.8% negative predictive value, with a sensitivity of 99% and specificity of 12.9%.
    
    
  • Plain radiographs
    
    
    
    • A complete set of images of the cervical spine includes the following:
      
      
      
      • The anteroposterior (AP) view, lateral view, and open-mouth odontoid view.
        
      • To be able to evaluate all possible injuries, images should include C1 through T1.
        
      • In patients whose body habitus obstructs the view of the lower cervical vertebrae, a swimmer’s view can be obtained to better evaluate this region.
      
      
    • Based on the most recent Eastern Association for the Surgery of Trauma (EAST) guidelines in 2009, CT scanning has replaced radiography as the primary screening tool for cervical spine injury in the trauma patient.
      
    • Thoracic and lumbar images can be obtained in patients with pain, tenderness to palpation, or neurological deficits.
    
    
  • Computed tomography (CT)
    
    
    
    • With coronal and sagittal reconstructions, the CT is better at identifying bone fractures in the spinal column with a sensitivity of almost 100%.
      
    • Patients with persistent pain despite normal radiographs should be considered for CT imaging.
      
    • CT remains the diagnostic method of choice in most trauma centers for diagnosis of c-spine injury after major trauma. For patients with mild to moderate mechanism of injury, there are no clear recommendations and practitioners must weigh the risks and benefits of plain radiographs versus CT scan.
    
    
  • Magnetic resonance imaging (MRI)
    
    
    
    • MRI is able to identify injuries to the spinal cord, in addition to ligamentous, intervertebral disk, and soft tissue injuries.
      
    • There are several contraindications to emergent MRIs:
      
      
      
      • Patients who are transported for MRI must be clinically stable, as these images take longer to acquire, and the machines are often located farther away from the treatment area.
        
      • Pacemakers, cochlear implants, metallic implants or foreign bodies (such as bullets), and certain stents also pose contraindications to MRI scanning.

Critical management

• Airway and breathing
  
  
  
  • Consider early intubation for all patients with cervical spinal cord injuries who demonstrate any signs of inadequate ventilation or oxygenation in order to minimize secondary spinal cord injuries.
    
  • High cervical spine injuries may result in chest wall weakness, and inability to take deep breaths. Some patients may display paradoxical breathing, with the chest going inward and the abdomen distending during inspiration. Such patients should be intubated early to minimize the work of breathing and fatigue that can result.
    
  • Care should be taken during the intubation of patients with cervical spine injuries to minimize any movement of the neck that may cause worsening of the injury. The use of airway adjuncts, such as video laryngoscopy or fiberoptic techniques, may be preferable to direct laryngoscopy.
  
  
• Cardiovascular
  
  
  
  • Hemorrhagic shock
    
    
    
    • Hypotensive, hemodynamically unstable trauma patients should be presumed to have a hemorrhagic shock until proven otherwise.
      
    • These patients should be treated quickly with intravenous fluids, followed by blood products and source control, to minimize further neurological deterioration due to secondary spinal cord injury.
    
    
  • Neurogenic shock
    
    
    
    • Neurogenic shock can result in hypotension and bradycardia.
      
    • Treatment includes intravenous fluid, followed by vasopressors as needed to ensure perfusion of the spinal cord.
    
    
  • Autonomic dysreflexia
    
    
    
    • Patients with spinal cord injuries above the level of the sympathetic outflow (T5–T6) may suffer from autonomic dysreflexia, with episodic bouts of significant hypertension, diaphoresis, flushing of the skin, and bradycardia.
      
    • Care of these episodes is supportive, including treatment of reversible causes, such as bladder distension, fecal impaction, or any irritating stimulus below the level of the injury.
  
  
• Glucocorticoids
  
  
  
  • This topic is controversial; however, multitrauma patients with spinal injuries should not receive high-dose steroids.
    
  • While some animal studies found that steroids can decrease spinal cord edema and improve neurological function, such experiments have not been replicated in humans.
    
  • The National Acute Spinal Cord Injury Study (NASCIS) II study found no significant difference in neurological function between traumatic spinal cord injured patients treated with methylprednisolone, naloxone, or placebo. However, there were modest improvements in those treated within 8 hours.
    
  • The NASCIS III study found that patients treated between 3 and 8 hours after their injury had modest motor, but no significant functional recovery. Those with longer infusion of steroids had a higher rate of sepsis and pneumonia.
    
  • While steroids remain a treatment option, this decision should be made in conjunction with the trauma and neurosurgical services that will provide continued care for the patient.
  
  
• Surgical options
  
  
  
  • Closed reduction
    
    
    
    • Considered in patients with cervical spine injuries with subluxation and neurological deficits.
      
    • Not used in thoracic or lumbar injuries.
    
    
  • Surgical indications
    
    
    
    • Spinal cord compression with neurological deficits
      
    • Unstable vertebral fracture or dislocation
      
    • Penetrating injuries with imbedded foreign bodies in tissues, to prevent wound infection
  
  
• Experimental treatments
  
  
  
  • Spinal cord cooling
    
  • Electrical stimulation
    
  • Neural stem cells

References

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