Sunderland classification of nerve injuries

Last reviewed 01/2018

Sunderland described a classification of nerve injuries in 1951 that correlates pathological changes with prognosis. The grades are:

• first degree injury:
  • demyelinated nerve
  • a physiological local conduction block
  • neuropraxia in the Seddon scheme
  • conservative management
  • recovery expected over weeks to months
• second-degree injury:
  • some axons disrupted
  • endoneurial sheaths and surrounding connective tissue layers remain intact
  • Wallerian degeneraiton distally
  • equivalent to axonotmesis in Seddon scheme
  • treatment is conservative
  • regeneration of axons can be followed clinically by an advancing Tinel's sign
  • complete recovery can be expected over months
• third-degree injury:
  • axons and endoneurial sheaths disrupted
  • scarring replaces existing structures
  • perineurium and connective tissue layers outside of this remains
  • most of these injuries will recover spontaneously but partially
• fourth-degree injury:
  • axon, endoneurium and perineurium disrupted
  • scarring replaces existing structures
  • epineurium remains
  • scar blocks all neuronal regeneration
  • no recovery likely without operative management
• fifth-degree injury:
  • nerve transection
  • all structures including epineurium divided
  • no recovery expected without operative management

Sixth-degree injury was subsequently added to the scheme by Susan Mackinnon. This describes a nerve injury with features of two or more of the above categories.