Compression Neuropathy Flashcards
Definition of compression neuropathy?
process why a nerve becomes entrapped and it passes through a narrowing (tunnel, passage, etc). Can happen anywhere along length of a nerve
Biomechanical causes of CN
space occupying lesions, degenerative causes, post-trauma, mechanical/movement, spondylolisthesis
ex of space occupying lesions
herniated discs, cysts
ex of degenerative cause of CN
foraminal stenosis
ex of post-trauma cause of CN
fracture, hematoma, compression from equipment
ex of mechanical/movement cause of CN
muscle spasm, pinching from external or positional forces
Systemic causes of CN
pregnancy, hypothyroidism, diabetes
Anatomy of a nerve from inside out
axons covered by myelin sheath covered by endoneurium > grouped together in fascicles and covered by perineurium > groups of fascicles and the vessels and CT are surrounded by epineurium
microscopic pathological changes (of the nerve) that can be seen in CN
microvascular compressions (leading to ischemia), thickening of epineurium, thinning of myeline sheath, microtubular closure, axonal degeneration
What category of nerve injury is Neuropraxia? and what is it?
Neuropraxia = 1st degree injury.
involves focal damage of myelin fibers around the axon, but the CT sheath remains intact
Recovery: limited course from days to weeks (lease severe)
What category of nerve injury is axonotmesis and what is it?
Axonotmesis = 2nd degree injury.
There is some disruption/injury to the AXON itself, MYELIN SHEATH remains INTACT.
Recover: REGENERATION is possible, but PROLONGED (takes months) without a complete recovery
What category of nerve injury is neurotmesis?
Neurotmesis: can be a 3rd or 4th or 5th degree nerve injury
What would a 3rd degree nerve injury look like?
Neurotmesis
-disruption of the axon AND the endoneurium
Recovery: No axonal regeneration because there is INTRANEURAL FIBROSIS
What would a 4th degree nerve injury look like?
Neurotmesis
-disruption of the AXON and ENDONEURIUM and PERINERIUM (aka nerve fasciculi). There will be a large area of INTRANEURAL SCARRING at site of injury = prevents axon from advancing distal to the level of injury.
Recovery: if be NO IMPROVEMENT in function…need SURGERY to restore
What would a 5th degree nerve injury look like?
Neurotmesis
-disruption of the AXON and ENDONEURIUM and PERINEURIUM and EPINEURIUM. There will be substantial perineural HEMORRHAGE and SCARING.
Recovery: surgery is required
Name of the system that classifies nerve injury
Sunderland Classification (1st degree - 5th degree)
What can you use to identify where/what nerve is pinched?
used dermatomes/sensation, motor, and reflex nerve roots to narrow it down
If you impinge nerve root C5 where will you see changes (motor, sensation, reflex)?
Motor: deltoid, biceps
Sense: lateral arm
Reflex: biceps
If you impinge nerve root C6 where will you see changes (motor, sensation, reflex)?
M: wrist extension, elbow flex
S: radial forearm, thrum and index finger
R: brachioradialis
If you impinge nerve root C7 where will you see changes (motor, sensation, reflex)?
M: wrist flex, elbow extension, finger extension
S: middle finger
R: triceps
If you impinge nerve root C8 where will you see changes (motor, sensation)?
M: finger flexion
S: ulnar forearm, pinky finger
If you impinge nerve root T1 where will you see changes (motor, sensation)?
M: finger abduction
S: medial arm
Most common cause of cervical nerve root compression?
usually a secondary manifestation of cervical disc disease (bulging disc or disc herniation)
What type of damage will you see in bulging disc
disc is compressed evenly without significant damage to the cartilage rings