Input the advancement distance and time elapsed to calculate the nerve regeneration velocity and biological status.
Guidelines & Evidence
Clinical Details
Section 1
When to Use
When to Use
Monitoring a patient with a known closed nerve injury (e.g. radial nerve palsy after humerus fracture).
Quantifying whether expectant management is working or if the patient needs immediate referral to a peripheral nerve surgeon for grafting.
Section 2
Literature
Development
First described independently by Jules Tinel and Paul Hoffmann in 1915 during WWI. When an axon regenerates, its advancing tip (the growth cone) is unmyelinated and highly mechanically sensitive. Tapping over the nerve precisely at the location of these growth cones triggers an "electric shock" sensation shooting down the limb. By marking this spot on the skin with a pen during each visit, surgeons can literally track the nerve healing in real-time.
Section 3
Pearls/Pitfalls
The 1 mm/day Rule
The absolute speed limit of mammalian Wallerian regeneration is roughly 1 millimeter per day (or about 1 inch per month). If a patient injures their brachial plexus, and the target muscle (biceps) is 15 inches away, it is physically impossible for them to regain function before 15 months, dictating long-term physical therapy planning.
Section 4
Evidence Appraisal
Primary Reference
Le signe du "fourmillement" dans les lésions des nerfs périphériques
