nerve injury Flashcards
what are the 2 injuries associated with fractures
neurapraxia or axonotmesis
neuropraxia
occurs when there is temporary conduction defect caused by compression of stretch, it resolves over time with full recovery (may take up to 28 days)
axonotmesis
occurs due to substantial compression or stretch, the nerve remains in continuity and its internal structure is intact but the long nerve cell axons distal to the point of injury die in a process called WALERIAN degeneration, with time the axons then regenerate along the endoneural tubes at a rate of 1mm a day
recovery of axonotmesis
is variable and full power of sensation may not return, recovery can be predicted by nerve conduction studies after one month from initial injury
neurotmesis
is complete transection of a nerve and is rare in closed injuries but can occur in penetrating injuries, no recovery will occur unless it is surgically repaired and outcome is still variable
majority of nerve injuries associated with a fracture
resolve with time
surgery for neve injuries
is not indicated unless there is evidence of nerve entrapment with severe neuralgic pain
what is a nerve injury occurs after a fracture manipulation
assumed that nerve is trapped in fracture site
if recovery from axonotmesis or neurotmesis is poor
nerve grafting (using dispensable cutaneous nerve) and tendon transfers can be carried out to improve function
colles fracture may cause
acute median nerve compression
anterior dislocation of shoulder may cause
axillary nerve palsy with loss of sensation to regimental badge area
humeral shaft fracture may cause
radial nerve palsy causing wrist drop (the radial nerve is contained within spiral groove of humerus)
supra- condylar fracture of elbow may cause
median nerve injury ( usually anterior interosseous branch)
posterior dislocation of the hip may cause
sciatic nerve injury
bumper injury to lateral knee may cause
common fibular nerve palsy causing foot drop
