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2011-10-02 21:44:54
Spinal Cord Injury

Spinal Cord Injury
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  1. Spinal Cord Injury
    • 11,000 new cases annually
    • 50% of SCI involve the cervical spine
    • Before WWII; life expectancy up to 10 years following injury
    • Cause of death: renal failure & sepsis
    • Improved treatment strategies
    • Now the SCI patient life expectency only 5 years less than the general population
  2. Tetraplegia aka Quadriplegia
    • Paraysis of both arms and legs
    • If death occurs in a patient with tetrapledia is is usually realted to compromised respiratory function
  3. Etiology & Pathophysiology
    • Greatest risk for SCI are males between age of 16-30 years
    • 78% of people with SCI are male
    • Most common age of injury is age 19 (male)
  4. Causes of SCI Trauma
    • MVA - 50%
    • Falls - 24%
    • Vilolence - 11%
    • Sports Injuries - 9%
    • Misc - 6%
    • Note: In large urban areas gunshot wounds may surpass falls as a cause of SCI
  5. Initial Injury Causes
    • Cord compression by bone displacement
    • Interuption of blood supply to the cord
    • Traction resulting from pulling on the cord
    • Penetrating trauma, such as a gunshot wound or stab wounds can result in tear or traction
  6. Primary Injury
    • The initial mechanical disruption of axons as a result of stretch or laceration
    • Small perivascular hemorrhages, especially in gray matter of cord - ischemia/infarction
    • Edema may produce transient loss of function
  7. Secondary Injury
    • Occurs minutes to hours after primary injury
    • White matter edema
    • Microcirculation of the cord is impaired
    • Release of norephinephrine/serotonin/dopamine/histamine
    • --Vasospasms and further reduction in circulation
    • --Ischemia/necrosis/paralysis=irreversible
    • Because secondary injury occurs over time, the exent of injury may not be most accurately determined until after 72 hours or more
  8. Spinal Shock
    • Occurs in about 50% of people with SCI
    • Characterized by decreased reflexes, loss of sensation, and flaccid paralysis below the injury site
    • Lasts days to months and may mask postinjury neurologic function
  9. Neurogenic Shock
    • Due to the loss of motor tone caused by the injury
    • Characterized by hypotension and bradycardia
    • --Loss of sympathetic nervous system innervation causes peripheral vasodilation, venous pooling and decreased CO
    • Generally assocaited with a cervical or high thoracic injury
  10. Classification of Spinal Cord Injury
    • Mechanism of Injury
    • Skeletal and neurologic level of injury
    • Completeness or degree of injury
  11. SCI - Mechanisms of Injury
    • Flexion: injury of the cervical spine reptures the posterior ligaments
    • Hyperextension: injury of the cervical spine reptures the anterior ligaments
    • Flexion-Rotation: most unstable of all injuries because the ligamentous structures of that stabilize the spine are torn. This injury is most often associated with the most severe neurological deficits.
    • Extension-Rotation:
    • Compression: compression fractures crush the vertebrae and force bony fragments into the spinal canal
  12. SCI - Level of Injury
    • Skeletal Level: is the vertebral level where there is the most damage to vertebral bones and ligaments
    • Neurologoc Level: the lowest segment of the spinal cordwith normal sensory and motor function on both sides of the body
    • --The level of the injury can be cervical, thoracic or lumbar.
    • --Cervical and lumbar are the most common b/c these are associated with the most flexiblity and movement
    • --If the cervical cord is involved it can result in tetraplegia, however if damage is high on the cervical cord the arms are rarely completely paralyzed
    • --If the thoracic or lumbar cord is damaged, the result is paraplegia