13. How would you treat neurotmesis? What is the prognosis?
Correct answer: Operative repair using an operating microscope is usually required. If a section of the nerve has been lost such that approximation is not possible, the nerve is freed proximally, or even moved from its original position to a…
12. How would you treat neurapraxia and axonotmesis?
Correct answer: Those joints whose muscles have been paralysed are splinted in the position of function to avoid contractures. They are put through passive movements several times a day so that, when recovery of the nerve lesion occurs, the joint…
11. What special investigation would you use to investigate peripheral nerve injury?
Correct answer: Electromyography (EMG) plays an important part in the diagnosis and assessment of nerve injuries. Serial studies are useful in demonstrating the amount and rate of regeneration. EMG is also useful in the diagnosis of nerve compression syndromes.
10. What are the commonest causes of a partial nerve injury?
Correct answer: Partial nerve injury may occur as the result of pressure or friction, for instance from a crutch, a tightly applied plaster cast or a tourniquet, as well as from closed injuries or open wounds.
9. Can different severities of nerve injury occur within the same nerve?
Correct answer: Because a peripheral nerve contains a large number of individual fibres it is quite possible in a nerve injury for some fibres to suffer from neurapraxia, others axonotmesis and others neurotmesis. However, a distinction between the first two…
8. What is neurotmesis?
Correct answer: Actual physical disruption of the peripheral nerve. Regeneration will take place provided the two nerve ends are not too far apart, but functional recovery will never be complete. Following the complete disruption of neurotmesis, the distal part of…
7. What does the time to recovery following an axonotmesis depend on?
Correct answer: The nerve will regenerate at a rate of 1 mm/day, so the time to recovery depends on the distance between the injury and the end organ.
6. What is Wallerian degeneration?
Correct answer: In axonotmesis the axon distal to the lesion degenerates and regrowth of the axon occurs from the node of Ranvier.
5. What is axonotmesis?
Correct answer: Injury to the axon and myelin sheath without disruption of the continuity of its perineural sheath. The axon distal to the lesion degenerates (Wallerian degeneration) and regrowth of the axon occurs from the node of Ranvier proximal to…
4. What is neurapraxia?
Correct answer: Damage to the nerve fibres without loss of continuity of the axis cylinder; this is analogous to concussion within the central nervous system. The conduction along the fibres is interrupted for only a short period of time. Recovery…
