Peripheral Nerve Injuries: General Approach

Neurapraxia (Sunderland Grade I): Nerve fibres are intact, there is only a conduction block. Full spontaneous recovery is expected (days-weeks). Example: "Saturday night palsy" (radial nerve compression from sleeping on an armchair).

Axonotmesis (Sunderland Grade II-III): Axons are damaged but the nerve sheath (perineurium) is intact (Grade II) or partially damaged (Grade III). Spontaneous recovery is possible but slow.¹ Nerve regeneration progresses at a rate of approximately 1 mm per day.² Surgery may be required in Grade III.

Neurotmesis (Sunderland Grade IV-V): The nerve is completely severed (Grade V) or surrounded by severe scar tissue (Grade IV). Surgical repair is mandatory.³

Diagnosis and Evaluation

Detailed neurological examination: motor strength (0-5 scale), sensory testing (touch, pinprick, two-point discrimination), reflexes. The optimal timing for EMG/nerve conduction studies depends on the clinical question; although traditionally recommended to be performed after 3-4 weeks, important information can also be obtained in the first week.^4,5 Nerve continuity can be evaluated with ultrasound.

Surgical Techniques

Primary Repair: In sharp cutting instrument injuries, the nerve ends are sutured directly (epineurial or fascicular repair). A tension-free end-to-end anastomosis is ideal.

The sural nerve (calf) is the most frequently used donor nerve.

Nerve Transfer: If the regeneration distance is too long, a non-functional nerve branch is redirected to the target muscle. E.g.: spinal accessory nerve → suprascapular nerve (for shoulder abduction).

Tube Repair: Bridging with a biological or synthetic nerve tube in small defects (< 3 cm).⁶

Tube Repair: Bridging with a biological or synthetic nerve tube in small defects (< 3 cm).

Timing

→ Next page: S46 — Brachial Plexus and TOS

Spontaneous recovery is possible but slow; nerve regeneration progresses by approximately 1 mm per day.