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Clinical Conditions II > Final - Peripheral Nerve Injuries > Flashcards

Final - Peripheral Nerve Injuries Flashcards

1
Q

Etiology of Nerve Injuries

A
  • Tension: stretch injury
  • Compression: tumor
  • Trauma: penetrating wound
  • Ischemia: diabetic neuropathy
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2
Q

Pathophysiology of nerve injuries

A
  • injury may result in demyelination or axonal degeneration
  • results in disruption of the sensory and/or motor function of the injured nerve
  • specific sensory deficits and weakness depend on which nerve has been affected and the location of the injury
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3
Q

Wallerian Degeneration

A
  • injury to an axon
  • cell body nucleus recognizes that something in the periphery has changes
  • Retrograde loss of the axon to at least the first uninjured Node of Ravier
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4
Q

What does Wallerian Degeneration cause?

A
  • increase in cell body size
  • migration of the nucleus to the periphery
  • increased protein and RNA metabolism
  • myelin phagocytosis
  • muscle atrophy
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5
Q

How is Wallerian Degeneration fixed?

A
  • schwann cell proliferation
  • axonal sprouting
  • possible increased activity of nerve growth factor
  • Axonal regeneration at a rate of 1-4 mm/day
  • contact with appropriate distal target cell and synapse is formed
  • “unused” sprouts are reabsorbed
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6
Q

What can form when nerve regeneration is unsuccessful?

A

neuroma

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7
Q

Partially successful nerve regeneration

A
  • axonal regeneration to the incorrect distal target

- decreased target tissue viability

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8
Q

What correlates closely with the prognosis of recovery?

A

the nerve injury classification

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9
Q

first degree injury

A
  • Seddon’s neuropraxia
  • Localized conduction block but axon remains viable
  • Focal demyelination may occur
  • Recover is usually complete 2-3 weeks
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10
Q

Second Degree Injury

A
  • Seddon’s Axonotmesis
  • Injury to axon
  • Supporting structures are intact
  • Wallerian degeneration occurs
  • Recovery at 1mm/day as axon follows connective tissue tubule
  • can be monitored with an advancing Tinel’s sign
  • recovery is poor in lesions requiring > 18 mo to reach target site
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11
Q

Third Degree Injury

A
  • Seddon’s Axonotmesis
  • Endoneurium is disrupted
  • Perineurium and epineurium are intact
  • recovery may range from poor to complete and depends on the degree of intrafascicular fibrosis
  • nerve may not appear seriously damages on gross inspection
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12
Q

Fourth Degree Injury

A
  • Seddon’s axonotmesis
  • Interruption of all neural and supporting elements
  • epineurium is intact
  • the nerve is usually enlarged
  • Tinel’s sign does not advance
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13
Q

Fifth Degree Injury

A
  • Seddon’s Neurotmesis

- Complete Transection wit loss of continuity

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14
Q

sixth degree injury

A
  • recently introduced by MacKinnon

- Mixed nerve injury –> some fascicles of a nerve are working normally while other fascicles may be recovering

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15
Q

Proper Diagnosis of Nerve Injury

A
  • History
  • strength and sensory testing
  • nerve conduction studies
  • EMG
  • imaging studies (MRI and CT scans) for suspected brachial plexus avulsion injuries or tumors
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16
Q

Medical Management of Open Injuries

A
  • immediate exploration of the nerve following a laceration
  • nerve repair if indicated:
    approximate nerve ends and suture together
    microscopic technique (microsurgery) to align internal fascicles
    limit amount of tension
17
Q

Nerve Tension

A
  • intraneural pressure increases with tension of nerve

- blood supply is compromised

18
Q

Nerve Grafts - Indications

A
  • tissue loss
  • tension with approximation of nerve endings
  • tension on nerve with joint movement
19
Q

Nerve Grafts - Autografts

A
  • sural nerve

- medial cutaneous nerve of the forearm

20
Q

Nerve Grafts - Allografts

A

need for immunosuppression medication - no longer necessary

21
Q

Nerve Grafts - nerve conduits

A
  • silicon tubes

- neurotubes

22
Q

Nerve Transfers

A
  • use of viable nerve which is sacrificed to its target tissue to reinnervate a new target tissue
  • generally used for motor function
23
Q

Medical Management of Closed Injuries

A
  • symptom management
  • Periodic rechecks for recovery –> clinical observation/testing, electrodiagnostic testing
  • surgical exploration 3 months after injury if no improvements is noted
  • crush injuries are similarly managed
24
Q

Medications for Nerve Pain

A
  • antidepressants
  • anticonvulsants
  • Baclofen
25
Q

General therapeutic management

A
  • protection of anatomical structures from further stresses
  • pain management
  • prevention of PROM loss
  • prevention of strength loss in unaffected musculature; unable to strengthen affected musculature
  • pt education (diagnosis/therapy process, compensatory strategies for loss of function)
26
Q

Therapy following surgical management

A
  • period of immobilization to avoid tension on nerves
  • edema management
  • scar management
27
Q

Developmental consideration in therapy

A
  • lack of compressive and tensile forces may affect normal bone and muscle development
  • inability to get into normal developmental positions may cause tissue tightness
28
Q

Presentation of Brachial Plexus Upper Trunk Injury

A
  • upper trunks of brachial plexus (c5 and c6)
  • most commonly injured
  • mechanism of injury is forcible increase in the angle between the neck and the shoulder
  • muscles in C5 and C6: shoulder abductors, elbow flexors and supinators, wrist extensors
  • Sensory deficits in the C5 and C6 dermatomes - lateral arm, forearm, and hand
29
Q

Therapeutic Management for Upper Brachial Plexus Injury

A
  • Problems: shoulder stability compromised
  • Pain management: muscle tightness related to muscular imbalance –> STM to decrease tightness
  • patient education: exercises to maintain PROM, functional compensatory strategies, safety for sensory deficits
30
Q

Presentation of Radial n injury

A
  • common mechanisms of injury are mid shaft humeral fracture, trauma, saturday night palsy
  • musculature affected: elbow extensors, wrist, thumb, and MCP joints of digits depending on site of injury
  • small area of sensory deficit in the posterior and lateral thumn
  • classic presentation is wrist drop
  • unable to effectively use finger flexors because of synergistic function of wrist extensors needed
30
Q

Therapeutic Management for Radial Nerve injury

A
  • splint to position wrist in extension
  • pt education:
    contracture prevention
    compensatory function strategies
    HEP
31
Q

Medical Management for Unresolved Nerve Injury

A
  • tendon transfer –> transfer tendon of a working muscle to the tendon of a muscle with no nerve supply
32
Q

E Stim

A
  • In theory, can be used to prevent muscle atrophy
  • inclusive research
  • muscle tissue can be directly stimulated with direct current
  • questionable, peripheral nerve injury application because sensation over the muscle belly to be stimulated generally is intact

Clinical Conditions II (11 decks)

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