- Question
- How should nerve conduction studies and electromyography be timed and interpreted after traumatic nerve injury?
- Design
- Narrative review of the pathophysiology and electrodiagnostic assessment of nerve trauma.
- Patients
- Patients with traumatic peripheral nerve injuries.
- Intervention
- Nerve conduction studies and needle EMG at defined intervals
- Comparison
- Not applicable
- Primary outcome
- Ability to localise and grade the lesion and predict recovery
- Key result
- Electrodiagnosis helps localise the lesion and quantify axon loss, but distal conduction persists for a period after transection, so studies are most informative once Wallerian degeneration has occurred; EMG evidence of reinnervation precedes clinical recovery.
- Limitations
- Narrative review rather than primary data; electrodiagnosis still cannot distinguish an in-continuity axonotmesis from neurotmesis early.
- Impact on practice
- Explains why very early nerve studies after injury can falsely reassure and why baseline studies are usually deferred for a few weeks, with serial studies to detect recovery.