Hi Sharon,
For BPI, the nerve injury can be classified using Seddon Classification or Sunderland Classification. I feel like the most common way we see is with Seddon’s terminology (neuropraxia, axonotmesis, neurotmesis). See classifications below and how they relate to each other (you can see there is some overlap)
Seddon –> Sunderland
Neuropraxia –> First degree
Axonotmesis –> Second and third degree
Neurotmesis –> Third, forth, and fifth degree
Sunderland Classification descriptions:
First degree: demyelinated nerve; a physiological local conduction block; conservative management; recovery expected over weeks to months
Second degree: some axons disrupted; endoneurial sheaths and surrounding connective tissue layers remain intact; Wallerian degeneration distally; treatment is conservative; complete recovery can be expected over months
Third degree: 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
Forth degree: axon, endoneurium, and perineurium disrupted; scarring replaces existing structures; epineurium remains; scar blocks all neuronal regeneration; no recovery likely without operative management
Fifth degree: nerve transection; all structures including epineurium divided; no recovery expected without operative management
Apparently there is a sixth degree that I wasn’t aware of that describes a nerve injury with features of two or more of the above categories.
Let me know if this helps clear things up!
Jessica