Classification
Grade 1: Neuropraxia
- Conduction disruption with intact axon and preserved supportive structures
- Prognosis: Normally full recovery in days to weeks without surgical intervention
Grade 2: Axonotmesis
- Disrupted axon with intact endoneurium; Wallerian degeneration takes place after 1-2 weeks
- Prognosis: Variable recovery, worse prognosis for proximal injuries and injuries that do not successfully re-implant in the muscle within 18 months
Grade 3: Neurotmesis with preservation of perineurium
- Endoneurium is disrupted
- Prognosis: 60-80% recovery
Grade 4: Neurotmesis with preservation of epineurium
- Prognosis: Nerve grafting is required
Grade 5: Neurotmesis with complete transection of nerve trunk
- Prognosis: Bypass/jump grafting is required
Explanation
There are two classification schema used to describe nerve injuries. The first was published by Seddon in 1943, and separated injuries into three categories — neuropraxia, axonotmesis, and neurotmesis — largely based on the scale of injury from microscopic to macroscopic. In 1978, Sunderland expanded upon this idea, subdividing neurotmesis into three additional grades. The Seddon classification is useful to understand the anatomic basis for injury, while the Sunderland classification adds information useful for prognosis and treatment strategies.
Figures
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Reference(s)
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