Spinal Cord Injury Classifications Flashcards
Two categories of Spinal Cord injury
traumatic (result of external physical impact) and non-traumatic (result of disease, infection or tumour)
Etiology
Traumatic SCI typically occurs in the younger age group, 20-30 years of age, with male to female ratio of 4:1
Causes:
- 50% motor vehicle/motorcycle crashes
- 30% to 40% falls and work-related injuries
- cervical spine is most common region of injury
layers of spinal cord protection
Spinal cord is wrapped in tough layers of dura
Rarely torn or transected by direct trauma
Initial Injury: Spinal cord injury due to cord compression by
- bone displacement
- interruption of blood supply to cord
- tumour
Initial injury causes (2)
Cord compression
Penetrating trauma (gunshot or stab)
Primary Injury
Initial mechanical disruption of axons as a result of stretch or laceration
Secondary injury
ongoing, progressive damage that occurs after initial injury - caused by swelling from the immune system
within 24 hours after injury there is the development of edema, above and below the level of injury as a result of ischemic damage and may cause permanent cord damage - anything we can do to minimize secondary injury is crucial
Apoptosis
death of cells that occurs as a normal and controlled part of an organisms growth and development
occurs after initial injury and may continue for weeks or months after initial injury
Initial Injury: Autodestruction
Complete cord damage in severe trauma related to autodestruction of cord
- petechial hemorrhages are in central grey matter of cord shortly after injury
Addition results of secondary injury (3)
- Resulting hypoxia reduces oxygen tension below level that meets metabolic needs of spinal cord
- Lactate metabolites
- Increased vasoactive substances (norepinephrine, serotonin, dopamine) - at high enough levels these lead to vasospasms which leads to necrosis
Pathophysiology of secondary injury
- By < 24 hours, permanent damage may occur because of edema
- Edema secondary to inflammatory response is harmful because of lack of space for tissue expansion
- Results in spinal cord compression and extension of edema below and above injury which increases ischemic damage
Extent of neurological damage caused by spinal cord injury results from: (2)
Primary injury damage
Secondary damage
Primary injury damage
actual physical disruption of axons
Secondary damage due to (4)
Ischemia
Hypoxia
Microhemorrhage
Edema
Spinal Shock
What is it?
Characterized by (3)
TEMPORARY neurological syndrome
1. Decreased reflexes (means maybe they can return)
2. Loss of sensation
3. Flaccid paralysis below the level of injury
Experienced by about 50% of people with acute spinal cord injury
How long does spinal shock last?
This can last from days to months and may mask post-injury neurologic functioning. May mask what the patient is capable fo returning to. Acute shock state. People can often return to a much higher level of functioning than they initially seem to be capable of
Neurogenic shock
what is it?
Characterized by: 3
Caused by SCI at T5 or above
Loss of vasomotor tone caused by injury
Characterized by
1. hypotension, and non-compensating heart rate (bradycardia)
2. hypothermia
3. Loss of sympathetic innervation
Important clinical cues
Neurogenic shock: Hemodynamic Syndrome
Hemodynamic syndrome of massive vasocilation without compensation and results from the loss of sympathetic nervous system vasoconstriction tone caused by spinal cord injury
Loss of sympathetic nervous system innervation causes: (3)
- peripheral vasodilation
- venous pooling
- decreased cardiac output
Classification of SCI: classified by Mechanism of Injury (MOI) (3)
- skeletal level of injury
- neurological level of injury
- completeness or degree of injury
Major mechanisms of injury are (5)
- flexion
- hyperextension
- flexion-rotation (most unstable because ligamental structures that stabilize the spinal cord are torn- implicated in severe neurological deficits)
- extension-rotation
- compression
Level of Injury: Skeletal Level
Injury is at the vertebral level, where there is most damage to vertebral bones and ligaments
Level of Injury: Neurological Level
Lowest segment of spinal cord with normal sensory and motor function on both sides of the body
Level of injury may be: 3
cervical
thoracic
lumbar
Not sacral because the spinal cord ends by L1 and L2
what causes quadriplegia?
paralysis of all four extremities occurs (tetraplegia or quadriplegia) if the cervical cord is involved.
what causes paraplegia?
Paraplegia results if thoracic or lumbar cord is damaged
Phrenic nerve paralysis
C3-C5 – phrenic nerve damage. Diaphragm innervation is damaged. Dysfunction in capacity to breath
Degree of Injury: Complete Cord Involvement
results in total loss of sensory and motor function below level of lesion (injury)
Degree of Injury: Incomplete (partial) cord involvement
results in mixed loss of voluntary motor activity and sensation and leaves some tracts intact
Capacity to regain potentially much more function than complete
ASIA Impairment Scale
American Spinal Injury Association (ASIA) impairment scale
Commonly used for classifying severity of impairment resulting from spinal cord injury
Combines assessment of motor and sensory function
Determines neurological level and completeness of injury
Useful for:
- recording changes in neurological status
- identifying appropriate functional goals for rehabilitation
