Classify peripheral nerve injury.
Give the clinical features and management of very high radial nerve injury.
Ans:
Classification
of Peripheral Nerve Injury (Seddon & Sunderland)
Seddon’s Classification
1.
Neuropraxia
o Local conduction block without
axonal disruption
o Recovery: complete, within
days–weeks
2.
Axonotmesis
o Axonal disruption with intact
endoneurial sheath
o Wallerian degeneration occurs
o Recovery: spontaneous, but slow (1–3
mm/day)
3.
Neurotmesis
o Complete nerve
transection/disruption，包括 endoneurial tubes
o No spontaneous recovery
o Requires surgical repair
Sunderland’s Classification (More
Detailed)
1.
Grade
I – Neuropraxia
2.
Grade
II – Axonotmesis with intact
endoneurium
3.
Grade
III – Disruption of axon + endoneurium
(perineurium intact)
4.
Grade
IV – Only epineurium intact
5.
Grade
V – Complete nerve transection
6.
Grade
VI (mixed) – Mixed
injuries along segments of the same nerve
Very High Radial Nerve Injury
“Very high” =
injury proximal to the spiral groove, often
in the axilla (e.g., crutch palsy, posterior cord injury).
Clinical Features
Motor Loss
Because the
injury is proximal, all radial
nerve–supplied muscles may be involved:
In Axilla / High Posterior Cord:
·
Triceps paralysis → loss of elbow extension
·
Anconeus paralysis
·
Brachioradialis paralysis
·
Wrist
drop → loss of wrist extension
·
Finger
drop → loss of MCP joint extension
·
Loss
of thumb extension & abduction (EPL, EPB, APL)
Sensory Loss
·
Dorsum
of forearm (posterior cutaneous nerve of forearm)
·
Dorsum
of hand: radial 3½ fingers (variable)
Characteristic Clinical Signs
·
Wrist drop
·
Finger drop
·
Inability to supinate (biceps partly compensates)
·
Absent
triceps reflex (if lesion is
proximal enough)
·
“Saturday
night palsy” pattern if due to compression
Management
Initial / Acute Management
Depends on cause:
compression vs trauma.
1. Conservative Treatment (majority initially)
·
Rest,
avoid pressure (stop crutches causing compression)
·
Splinting:
o Dynamic
cock-up splint
to prevent wrist/finger flexion contracture
·
Analgesics,
NSAIDs
·
Physiotherapy
to maintain joint ROM
·
EMG/NCS
at 3–4 weeks to assess degeneration and prognosis
2. Indications for Early Surgery
·
Open
injuries with suspected transection
·
Penetrating
trauma
·
High-energy
humeral fractures with nerve discontinuity on imaging
·
No
clinical/EMG evidence of recovery after 3 months
3. Surgical Options
·
Primary nerve repair (if clean transection)
·
Nerve grafting (e.g., sural nerve graft) if
tension-free repair not possible
·
Nerve transfers in very proximal/posterior cord
injuries
o Median nerve branches → ECRB, PIN
·
Tendon transfers (if no recovery after ~6–9 months)
o PT → ECRB (wrist extension)
o FCR/FCU → finger extension
o Palmaris longus → EPL (thumb
extension)
4. Rehabilitation
·
Muscle
strengthening as reinnervation appears
·
Sensory
re-education
·
Functional
splints
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