Peripheral nerve injuries Flashcards
What is a peripheral nerve?
The part of a spinal nerve distal to nerve roots
What can cause nerve injuries?
Compression Trauma Neurapraxia Axonotmesis Neurometsis
What are classical conditions of entrapment?
Carpal tunnel syndrome
Sciatica
Morton’s neuroma
What is neuropraxia?
Conduction block without nerve degeneration - ischaemia
Is neuropraxia reversible?
Yes
What is axonotmesis?
Endoneurium intact but axons disrupted
Is axonotmesis reversible?
Slightly - function can return but often not normal
What is neurotmesis?
Complete nerve division
What happens as a result of endoneural tubes being disrupted?
‘Miswiring’ during regeneration
When is surgery indicated?
After 3 months if no recovery is identified
What is axonal growth rate?
1-3mm/day
What are clinical features of sensory nerve injury?
Dysaethesiae - anaesthetic(numb), hypo/hyperaesthetic, paraesthetic (pins and needles)
What are clinical features of motor nerve injury?
Weakness or paralysis
Wasting
Dry skin
What happens to reflexes in nerve injury?
Diminished/absent
What is the first modality to return in nerve healing?
Pain
What determines prognosis of recovery for nerve injury?
Whether nerve is pure (onlysensory or motor) or mixed
How distal lesion is - proximal is worse
What is Tinel’s sign?
Tap over site of nerve - paraesthesia felt as far distally as regeneration has progressed
What is the rule of three for peripheral nerve injury surgery?
Immediate surgery within 3 days for clean and sharp injuries
Early surgery within 3 weeks for blunt/contusion injuries
Delayed surgeries 3 months after injury for closed injuries
