What is the Sunderland nerve injury classification?

Grade 1 (neuropraxia): conduction block, full recovery. Grade 2 (axonotmesis): axon interruption, endoneurium intact, spontaneous recovery at 1 mm/day. Grade 3: endoneurium disrupted, incomplete spontaneous recovery. Grade 4: perineurium disrupted, nerve repair needed. Grade 5 (neurotmesis): complete transection, surgical repair required.

What is the nerve regeneration rate after repair?

Peripheral nerve regenerates at approximately 1 mm/day (1 inch/month). After surgical repair, re-innervation to target muscle = (distance from repair site to muscle in mm) / 1 mm per day. Muscles with long distances (>12 months) may undergo irreversible atrophy before reinnervation.

When should nerve repair be performed?

Sharp clean lacerations: primary repair within 72 hours. Crush/contaminated: delayed primary repair at 3-5 days. Stretch injuries: explore at 3-4 months if no recovery on EMG/NCS. Nerve grafting (sural nerve) for gaps >3 cm to avoid tension on repair.

Sunderland and Seddon Nerve Injury Classification

Apply Sunderland (1-5) and Seddon (neuropraxia, axonotmesis, neurotmesis) classification for peripheral nerve injuries. Guides prognosis for spontaneous recovery vs surgical nerve repair or grafting. Sunderland Grade 5 = complete transection, requires repair.

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