Peripheral Nerve Injury

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Peripheral Nerve Injury

• Neurosurgeon
• Yoon Seung-Hwan

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Anatomy

• Connective tissue
• - major tissue componant
• - epineurium, perineurium, endoneurium
• Nerve tissue
• - axon, schwann cell

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Peripheral Nerve Injury

• Acute injury
• Chronic injury
• (entrapment neuropathy)

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Classification
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Neuropraxia

• the mildest form, reversible conduction
• block
• loss of function, which persists for hours
• or days
• direct mechanical compression, ischemia,
• mild burn trauma or stretch

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Axontmetic

• axon continuity is disrupted
• fascicular integrity is maintained
• Wallerian degeneration occurs

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Neurotmesis

• laceration from sharp or blunt forces
• the only important consideration is
• the timing of repair
• acute repair or more bluntly lacerated
• nerves are repaired 3-4 weeks

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Factor s for Decision Making

• Age
• Segment between injury and end organ
• Gap of injury
• Mechanism of injury
• Severity of injury
• Presence of pain

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Axonal Regeneration

• Initial delay
• to the distal stump 1-2 week delay
• Growth rate
• 1mm/day, 1 inch/month
• Terminal delay
• several weeks-several months
• Recovery within 6 weeks? good prognosis

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Acute Denervation
Fibrillation potentials and positive sharp waves
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Regeneration
Long duration, small amplitude polyphasic motor
unit potentials
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Clinical Signs
Diagnosis

• Motor function
• Tinels sign
• positive-sensory function
• negative(after 4-6weeks)-total interruption
• Sweating-sympathetic fiber
• Sensory function

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Tinels sign

• advancing along the anatomical distribution of
  the nerve, particularly if it is does so at the
  expected rate of nerve regeneration, then this
  provides evidence of ongoing regeneration.

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Electrophysiological Tests
Diagnosis

• EMG
• SNAP
• SSEP
• Intraoperative NAP

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EMG
SNAP
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SSEP
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Intraoperative NAP
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Muscle Atrophy

• 24 month rule
• - 2? ?? ?? ? muscle scar tissue? ???? ?? ?
  (?????) ????
• Muscle atrophy
• start post-injury 1 month
• peak 3rd - 4th month
• Segment between injury and end organ

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Time of Operation
Treatment

• Open injury
• Early intervention
• Delayed intervention
• Closed injury
• Delayed intervention

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Early Intervention

• Enlarging hematoma/aneurysmal sac
• Predisposing to Volkmanns ischemic contracture
• Severe noncausalsic pain SD
• Injury to N. in areas of potential entrapment
• Simple, clean lacerating injury

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Delayed Intervention

• 2-3 months after injury
• No clinical or substantial recovery
• ??
• 1. ????? ??? ? ? ??.
• 2. ????? ??? ??? ???.
• 3. Epineurium? ???? ??? ??.
• 4. ????? ??? ??? ????.

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Operations

• Neurolysis internal/external
• Nerve repair
• end-to-end repair epineural/fascicular
• autologous graft sural N.
• Neurotization
• intercostal N./accessory N./cervical plexus
• within 1 year
• Muscle and tendon transfer

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Epineural Repair
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Fascicular Repair
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Nerve Graft

• leading cause of failure of nerve graft
• Inadequate resection
• Distraction of repair site

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Postoperative Care

• Neurolysis ?????? ????
• End-to-end repair 3? ?? ??
• 6??? ??? ??
• Graft ? ? ?? ?? ??
• ??? ????? ???

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Injured Peripheral Nerve
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Evaluation of Closed Injury
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Conclusions

• 1. Immediate primary repair in sharp injuries
  with suspected transsection of nerve
• Immediate repair is especially important for
  brachial plexus and sciatic nerve transsections
  because delay leads not only to retraction but
  also to severe scaring
• Bluntly transsected nerve best repaired after a
  delay of several weeks.
• A focally injured nerve should be explored if no
  functional return within 8-10 weeks
• 3. Decision - making as to whether neurolysis or
  resection repair in a lesion in gross
  continuity based on intraoperative
  electrophysiological evaluation

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Conclusions
4. Split repair with usually graft - lesion in
continuity? partial function or undergoing
partial regeneration 5. Careful patient selection
for operation - ?? plexus involved ? 6. Nerve
anastomosis ? failure ???? ? inadequate
resectin of scarred nerve ends ? nerve suture
distration 7. A good end result requiring
rehabilitation from onset of treatment.
Prevention of disuse, relief of pain, predicting
probable end results of operative procedures.
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Chronic Injuries of Peripheral Nerves by
Entrapment

• Pain
• Paresthesia
• Loss of function

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Pathophysiology of Entrapment

• Direct compression
• segmental demyelination
• wallerian degeneration(distal)
• Ischemia
• swelling of nerve
• microcompartment SD

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Conservative Tx
Treatment

• Indications
• not long history
• mild-moderate, intermittent
• reversible cause
• pregnancy, oral contraceptive, endocrine
  
  abnormalities(DM), type
  writer
• Method
• nonsteroidal anti-inflammatory drugs
• splint

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Surgical Indications
Treatment

• Failed conservative tx
• Typical clinical finding
• with electrodiagnostic data
• Severe
• sensory loss
• muscle atrophy
• motor weakness

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Entrapment of Thoracic Outlet

• ? ?
• - Cervial rib or anomalous transverse process
  of C7
• - Fibromuscular bands or scalene muscle
  abnomality
• ? ?
• - X-ray
• - NCV EMG
• - Angiography vascular anomaly
• Tx Supraclavicular approach
• - Best op. management

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scalene anterior and medius M.
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Carpal Tunnel Syndrome
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thenal atrophy
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Entrapment of Radial Nerve
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Entrapment of Ulnar Nerve - Cubital tunnel -
Guyons canal
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Motor Deficit of Ulnar Nerve

• Bediction posture clawing of ring small
  finger
• Froments sign weakness of adductor pollicis,
  there will be flexion of the interphalangeal
  joint of the thumb because of substitution of the
  median innervated flexior pollicus longus for a
  weak adductor pollicis

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Meralgia Paresthesia
Lateral femoral cutaneous nerve injury (L1-2)
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Tarsal Tunnel Syndrome