OR11.1 | Peripheral Nerve Injury Assessment and Splinting — Summary & Reflection

KEY TAKEAWAYS

Peripheral nerve injuries are classified by Seddon into neurapraxia (physiological block, full recovery), axonotmesis (axon disrupted, endoneurium intact, recovery by regeneration at 1 mm/day), and neurotmesis (complete division, no spontaneous recovery, surgery required). The five clinically essential nerve-injury pairs are: radial nerve → wrist drop → cock-up splint; ulnar nerve → claw hand (ring and little fingers) → knuckle-bender/lumbrical bar splint; median nerve → ape hand/loss of opposition → opponens splint; common peroneal nerve → foot drop → AFO; sciatic nerve → foot drop + hamstring weakness → AFO. Tinel's sign advances at 1 mm/day in a recovering nerve; if it is stationary at 8 weeks, surgical exploration is warranted. EMG/NCS at 3–4 weeks distinguishes neurapraxia (normal) from axonotmesis/neurotmesis (fibrillations). Splinting must be applied immediately to prevent contracture — the splint is not a treatment for the nerve injury but a prevention of secondary deformity. Closed injuries (e.g., humeral shaft fracture + radial nerve) are observed for 3–4 months; clean open lacerations should be referred for primary repair within hours to 3 weeks.

REFLECT

Consider a patient with a common peroneal nerve injury and foot drop whom you fit with an AFO today. What happens to that patient over the next 6 months — both to their nerve and to their walking ability — if the AFO is correctly fitted versus if it is not? How will you use Tinel's sign to follow them in an outpatient clinic without expensive equipment? Reflect on the ulnar paradox: how does it change how you explain to a patient why their less severe-looking wrist injury has produced a more functionally disabling claw hand than their friend's elbow injury from the same accident?