SCI Pathology and Intro Flashcards
spinal cord injuries (SCI) can be classified as _____ or ______
traumatic and non-traumatic
or
complete and incomplete
what is traumatic SCI?
- MVA, GSW, jumps and falls, diving
- MOI
- flexion (most common lumbar injury)
- flexion-rotation (most common cervical)
- compression
- penetration
- hyperextension (exclusively cervical)
- pathophysiology of injury types
- transection
- compression
- infection
- degenerative disease
spinal areas of greatest frequency of injury from traumatic SCI
- C5
- C7
- T12
- L1
what are some causes of non-traumatic SCI
- disc prolapse
- vascular insult
- infections
why are thoracic traumatic SCI less common than cervical?
rib cage and higher stability in the T/S compared to C/S
(if injured, T12-L1 is most common site of injury)
common MOI → flexion motion w/vertical compression
describe a typical traumatic lumbar injury
- Neurological damage from trauma is usually incomplete due to large vertebral canal and relatively good vascular supply
- most injuries occur at L1
- Most common MOI → flexion injury
briefly describe the demographics of SCI
- Demographics
- average age at injury → 43
- Males 78% of cases
- highest risk → males 20-29 yrs and 70+ yrs
most common site of injury in SCI
- Cervical (C4 and C5) and thoracolumbar junctions (T11 and T12)
- most mobile part of the spine
- more than half are cervical injuries, a third are thoracic and rest are lumbar
most frequent SCI
incomplete tetraplegia
T/F: the frequency of complete vs incomplete paraplegia is about equal
TRUE
what is the difference between tetraplegia and paraplegia?
- Tetraplegia
- injury to C/S cord (C1-C8)
- involvement of all 4 extremities and trunk
- Paraplegia
- injury to T/S or L/S regions of SC (T1-L5)
- involves BLEs and trunk
describe a complete SCI
- absence of sensory and motor function below lesion level
- more severe presentation of SCI
- Can have zones of partial preservation (ZPP)
- dermatomes and myotomes caudal to the sensory and motor levels that remain partially innervated
describe an incomplete SCI
- involves partial preservation of sensory and motor function below the lesion level
- better prognosis than complete SCI due to preserved axon function
- incomplete SCI occur more frequently than complete
how is the degree SCI (complete vs incomplete level of neuro injury) determined?
ASIA exam
how are SCIs acutely managed?
- primary goal → stabilize spine
- surgery
- external support devices
- Methylprednisone
- small window of opportunity: 3-8 hrs post injury
- stabilize cell membranes
- decrease inflammation
- increase nerve cell impulse generation
- improves blood flow to damaged area
- small window of opportunity: 3-8 hrs post injury
how does methylprednisone impact complete vs incomplete SCI?
- complete
- increases chances for return of function of the last preserved spinal level post SCI
- incomplete
- enhances return of some function below spinal level
list several pathological secondary sequelae of SCI
- Ischemia
- Edema
- Demyelination and necrosis of axons progressing to scar tissue formation
List some complications to SCI
- Spinal shock
- Autonomic Dysfunction
- Pressure Ulcers
- Postrual Hypotension
- Pain
- Spasticity
- Contractures
- Hetertrophic Ossification (HO)
- Edema
- DVT
- Osteoporosis and renal calculi
- Respiratory Compromise
- Bladder and bowel dysfunction
- Sexual dysfunction
what is spinal shock?
a temporary phenomenon with injuries T6 and above
- the cord in its entirety ceases to function below the lesion
- spinal reflexes, voluntary motor control, sensory function, and autonomic control are absent below the level of the lesion
- initially rapid dramatic increase in BP
- followed by steep decline in BP, HR, hypothermia, venous stasis
how long does spinal shock last?
usually 24 hours to several days post injury
1st thing to return is typically sacral/anal reflexes
why does spinal shock occur?
all sympathetic output occurs below T6 so its thought that an injury to this region wipes out communication between the SNS and CNS
ultimately resulting in a loss of sympathetic tone which presents like a LMN injury (even though its an UMN)
what is autonomic dysreflexia?
over-activity of the autonomic nervous system (due to loss of CNS control)