Week 8 - Peripheral Nerve Injuries Flashcards
- communication network btwn the CNS and the body parts
- consists of the nerves that branch out from the brain and spinal cord.
PNS
Name the 6 parts of the brachial plexus.
- roots
- trunks
- divisions
- cords
- branches
- digital nerves
How does PNI occur? Name 3 causes.
- trauma
- non-traumatic compression (nerve injury in continuity, compressed by anatomy)
- at birth
Name Seddon’s 3 classifications of PNI.
- neurapraxia
- axonotmesis
- neurotmesis
classification of PNIs is based on the degree of disruption of what?
internal structures of the peripheral nerve
nerve reconstruction is based on a foundation of principles that facilitate what?
the natural regeneration process of the nerve
Name 5 methods of PN repair.
- end to end repair
- conduit tube
- nerve graft
- nerve transfer
- muscle (tendon) transfer
injury - mild recovery; lowest and least severe, usually recovers on its own
neuropraxia
injury - severe; regeneration 1 mm day; recovery
axonotmesis
injury, degeneration, neuroma formation; nerve is cut or crushed
neurotmesis
- working muscles too hard
- repetitive movements
compressed by anatomy
a conduit tube is made out of what?
collagen
used when there is a large gap between nerve endings
nerve grafting
used after a nerve surgery to assess repair
advancing Tinel’s sign
nerve is taken from somewhere else in the body
nerve graft
- take a branch of working nerve and put it in nerve/muscle that is not working
- most popular
nerve transfer
what is the most common nerve used in nerve grafts?
surel nerve from leg is often used in median nerve grafts
how do you know whether to use a nerve graft or transfer?
method often depends upon how much of nerve is missing
- can’t move AROM or PROM for a few weeks
- quicker method
end-to-end repair
a surgical technique that may be used when a pt. has a nerve injury resulting in complete loss of muscle function or sensation
nerve transfer
involves taking nerves with less important roles - or branches of a nerve that performs redundant functions to others nerves - and moving them to restore function in a more crucial nerve that has been severely damaged.
nerve transfer
surgical treatment is mandatory when there is reasonable suspicion of what? and why?
a root avulsion or nerve rupture - such injuries are not expected to heal spontaneously
describe a nerve transfer for restoration of elbow flexion.
transfer of part of the ulnar nerve for re-inervation of the musculocutaneous nerve (biceps brachii muscle)
- nerve repair or graft not possible, unsuccessful
- to restore balance that has been lost through injury or disease
tendon, muscle transfer
- there is a predictable sequence of events
- axonal growth can be stopped anywhere along path by impenetrable scar
nerve regeneration
name 5 factors that influence regeneration.
- mechanical
- delay
- age of pt.
- level of injury
- associated injuries.
describe a tendon/muscle transfer.
- muscle on flexor surface is put into extensor surface
- we have to help pt. relearn how to extend wrist, fingers, etc. bc that muscle never worked in that way before
what always occurs during a muscle/tendon transfer?
pt. always loses a grade of muscle strength - important to tell pt. this
describe 3 changes to skeletal muscle after denervation.
- muscle ceases to function, there is gross atrophy
- decrease of muscle weight and cross sectional areas (no decrease in number of fibers)
- increase in connective tissue
what is the avg. rate of decrease in muscle mass after 1-3 weeks of denervation?
40%
functional re-innervation is unlikely after how many years?
2 years
what can play a role in preventing atropy?
NMES
Name 2 sensory changes after PNI.
- response of end organ varies - atrophy, degeneration, disappearance
- if sensory receptor degenerates after long-term denervation, it is lost the receptor pool bc we cannot form new sensory receptors
atrophy, never completely disappear
meissner and pacinian corpuscles
reduce in number, atrophy, become differentiated; atrophies faster than other sensory organs
merkel cells
skin color/temperature
vasomotor
sweat
sudomotor
gooseflesh response
pilomotor
- soft tissue atrophy
- nail changes
- hair growth
- rate of healing
trophic
describe early sympathetic changes after PNI.
- sudomotor: dry skin, rosy/warm
- pilomotor: absent
- trophic: soft/smooth, slight atrophy
- blemished nails
- healing slowed
describe late sympathetic changes after PNI.
- vasomotor: mottled/cyanotic/cool
- sudomotor: dry/moist
- pilomotor: absent
- trophic: non-elastic; pronounced, finger tip atrophy
- talon-like nails
- healing slowed
retrain pt. to recognize the distorted cortical impression; helps pt. achieve potential for functional sensory recovery given to him by the surgeon at the time of nerve repair
sensory re-education
Name 4 principles of sensory re-education treatment.
- pt. must have protective sensibility
- tasks are done with and without visual feedback
- environment free from distraction
- pts. must be motivated!
how often should sensory re-education intervention sessions occur?
brief session 2-4 times per day
describe the early phase of sensory re-education.
- perception of 30 cps vibration
- moving touch has returned
describe the late phase of sensory re-education.
-moving touch and constant touch can be perceived and localized at the fingertip.
*sensory re-education cannot be done until pt. has what?
at least protective sensibility
what should be done if pt. only has anesthetic sensibility?
pt. education (don’t touch stove, be careful with…)
the more ___ a nerve injury is the ___ it is to heal.
proximal, harder
- when stimuli that would not normally cause pain, causes severe pain in affected area.
- pts. typically hold affected part in protected position.
- can lead to disability through non-use of body part.
hypersensitivity
what is the OTs initial (first) treatment for hypersensitivity.
compensation and education
what is the second treatment that an OT utilizes for hypersensitivity?
“sensory desensitization” program
-OT introduces progressively irritating stimuli
Name 4 aspects of a baseline OT PNI evaluation.
- MMT
- Sensibility
- ROM
- ADL
what does MMT do in an evaluation?
helps determine level/extent of injury
what is the purpose of threshold sensibility tests in an OT eval?
to help determine nerve potential
what is the purpose of functional sensibility tests in an OT eval?
to help determine adaptation and compensation
which type of ROM should be used in a PNI OT eval?
PASSIVE
describe week 1 OT management of an acute PNI.
- post op dressing/cast to position joints to protect nerve repair
- AROM to non-involved joints
- elevation
describe day 7 OT management of acute PNIs.
- remove post op dressing/case, wound suture case, apply light dressing
- fabricate splint
- light compression may be indicated
- continue AROM of non-involved joints
- PROM of specific joints to prevent deformity
- patient education
describe one method of treatment for sensory re-education.
bucket of rice - try to find the marbles
person has enough sensibility in their fingers to pull away from something that would hurt them
protective sensibility
sensory desensitization is most common in pts. with which type of injuries?
finger injuries (digital nerve)
describe treatment for desensitization.
- gradually calm nerve down
- start with OT or pt. massaging their fingers, rubbing towel on them.
- rice bucket - prob wouldn’t start with this.
what kind of ROM would you perform in an initial OT eval if nerve doesn’t work?
PROM
Describe ROM interventions 3 weeks post injury.
- PROM of fingers to prevent contractures
- intrinsics are atrophied
How would you design/change a splint during day 7-21?
- wrist in neutral/extended if possible
- still full hand but want fingers to move more
when should you change a splint?
after 7-10 days
describe OT management of acute PNI during days 7-21.
- discontinue dressing when wound closes
- provide compression if indicated
- adjust splint to decrease angle of joints
- initiate light activities within confines of splint
describe OT management of acute PNI during days 22-35.
- discontinue splint with MD ok.
- scar massage and desensitization
- incorporate functional activities in therapy (discourage excessive force when gripping or manipulating objects, differential tendon glide, evaluate pts. psychological status)
- re-evaluate sensory and motor function
- document tinel’s
- emphasis on edema, scar management, prevention of deformity
Describe the progression of tendon gliding exercises.
- start with your fingers straight every time. (straight)
- make one type of fist at a time with your fingers - hook, straight, full, straight, straight fist.
- curl your thumb down in your palm as much as possible, then stretch it out as far as possible
when is NMES useful?
helpful when muscle is beginning to work, not when it’s deinnervated.
major part of PNI repair
orthotics
name 7 aspects of OT management of intermediate PNI.
- begin NMES when motor recovery is present.
- continue to incorporate functional activities.
- avoid “trick” or substitute motions
- begin UE strengthening program
- begin sensory re-education
- re-evaluate 2x/month
- emphasis on re-training and functional use while preventing deformity
Name 5 aspects of OT management of chronic PNI.
- pt. plateaued
- re-evaluate goals with pt.
- prioritize therapy for function
- continue methods to decrease deformity
- pt. education with rehabilitation team regarding reconstruction option - in preparation for tendon transfers, strengthen donor muscles, achieve full PROM
name 4 purposes of orthotics for PNI.
- splint to protect healing nerve or surgical repair
- splint to prevent deformity
- splint to facilitate function
- splint to correct deformity
what is a deformity of radial nerve PNI?
drop wrist/hand
name 4 deficits of radial nerve PNI/drop wrist/hand.
- loss of finger extension
- loss of wrist extension (high injury)
- loss of thumb extension
- decrease in forceful opposition
describe 4 aspects of splinting for radial nerve lesions.
- pts. have greater potential for normal use of hand
- provide radial palsy splint to enhance function
- forearm splint with outrigger
- called tenodesis splint sometimes
describe management of a LOW ulnar nerve PNI.
prevent overstretching of the denervated intrinsic muscles of 4th and 5th fingers.
describe management of a HIGH ulnar nerve PNI.
- splinting becomes mandatory as FDP to 4th and 5th fingers returns
- clawing is more evident
what would a strengthening program for PNI begin with?
isometric
describe a froment’s sign assessment.
- pt. holds a piece of paper while OT tries to grab it out of his/her hands.
- if finger flexes it’s a positive sign.
what does the bar in an ulnar nerve orthotic prevent?
hyperextension of MP joint - keeps them slightly flexed.
what is a deformity of median nerve PNI?
ape hand
name 7 deficits of median nerve PNI/ape hand.
- inability to oppose thumb
- decrease in web space
- inability to perform 3 jaw chuck
- decrease in power grasp
- decrease in FDS (high injury)
- decrease in FDP index and long fingers (high injury)
- decrease in pronation (high injury)
which contractures are most common in median nerve PNI?
adduction contractures of the thumb - addressed by proactive splinting
which PNIs are the most devastating and impactful on function regarding sensory loss?
median nerve injuries
- affects digits 4 and 5 at rest
- ulnar nerve lesion at the wrist
- loss of flexion at MCP joints and loss of extension at IP joints.
- lumbricals to digits 4 and 5 are paralyzed
ulnar claw hand
- affects digits 2 and 3 when attempting to make a fist
- median nerve is affected when there is a lesion at the wrist or elbow.
- lumbricals and FDP to digits 2 and 3 are paralyzed.
- loss of flexion at MCP joint and DIP joints.
- if pt. is asked to make a fist they will be able to flex digit 4 and 5 but not digits 2 and 3.
sign of benediction
Name 4 implications for OT practice.
- contractures - pt. should exercise AROM or PROM with the affected extremity when they are not wearing splint.
- performing ADLs with splints on
- one-handed techniques (temporarily)
- providing clear instructions to donning and duration or length of wear.
a muscle cannot work on a ___ joint.
fused
a ____ cannot work on a fused joint.
muscle
