Spinal Cord and Peripheral Nerve Injury Flashcards
Primary vs. Secondary Injury
Primary is damage done at event of injury (knife severing fibers), secondary is phys/pathological responses afterwards, notably edema and inflammation
Cyst
Area of central hemorrhage w/ surrounding rim of white matter/pia
ASIA Impairment Scale
Ranks SC injury from complete (A, no motor/sensory function) to incomplete (BCD) to normal (E) at the root level
Hypotensive vs. Neurogenic vs. Spinal Shock
Low BP, high HR vs. Low BP and HR from damage to SC at T6 or above to sympathetic NS (where most of it is) leading to vagal override of heart vs. temporary motor/sensory/reflex function below level of injury at time of injury
3 Main SCI Syndromes
Anterior Cord, Central Cord, and Brown Sequard
Acute Traumatic Central Spinal Cord Syndrome
Common: Elderly pts w/ stenosis experience hyperextension injury. Hand weakness > arms > legs, some sensory, gets better over time
Why Hand Most Affected W/ Corticospinal Lesions
NOT somatotopic, instead hand just has most fibers/control
Conus Medullaris Syndrome
Injury at T12/L1 - autonomics, and both U and LMN syndromes
Cauda Equina Syndrome
LMNs, so recovery better bc PNS
3 SCI Treatments
Steroids - don’t really work
Hypothermia - appear to work
Surgery
SCI Respiratory Effects
Especially at C6 or above bc ICs, but need respirator if C4 or above bc phrenic n.
SCI GI Problems
Oversecretion of acids so bleeding
Syringomyelia
Trauma results in hemorrhage/infarction w/in spinal cord leading to cyst formation
Neuropraxia
Least severe nerve injury - characterized by a conduction block and will resolve itself completely
Axonotmesis
More severe nerve injury, w/ disruption of axons but substance remains. Wallerian degeneration but then recovers well at nerve regeneration rate
Nerve Regeneration Rate
1 inch/month (1 mm/day)
Neurotmesis
Most severe nerve injury, w/ complete disruption of axons/substance, requires operative repair and recovery very variable
Ulnar Nerve Damage
Claw hand and hypothenar atrophy
Radial n. Injury
Can’t extend wrist or thumb, some sensory loss on posterior forearm/hand
Nerve Grafts
Take some of sural n. from leg, have to take more than distance b/w damaged nerve (if larger) to wrap around multiple times
