Operative
Complete Nerve Laceration
- Complete radial nerve lacerations in civilian practice are usually seen acutely and are usually caused by sharp lacerations from broken glass, knives, saws, or vehicular accidents.
- Complete nerve lacerations should be repaired with microsurgical procedures.
- Choices for microsurgical repair include:
- Epineural repair
- Group fascicular repair
- Nerve repair with nerve grafts
- Nerve repair with nerve conduit
- Nerve transfers (rare)
Partial Nerve Laceration
- Partial nerve lacerations can be repaired by dissecting the internal epineurium and isolating the transected fascicular groups, gently looping the intact fascicular groups and then repairing the cut fascicular groups by suturing the internal epineurial sheaths or by using nerve grafts for the cut fascicular groups is more likely to be needed.
- If there is a significant true defect, for example after a bullet wound, then repairing the cut fascicular groups with nerve grafts between the cut fascicular groups is indicated.
- Neurolysis of the radial nerve for a neuropraxia is uncommon.1,7
Nerve Grafting
- Nerve grafting is an accepted treatment modality for larger radial nerve defects, but it is less efficacious for adults. These are very reliable tendon transfers which will allow these patients to regain thumb, finger and wrist extension.5
- The Martin Singer treatment algorithm for radial nerve lacerations, which is based on patient age and whether the injury can be repaired, recommends the following:
- Patients <18 years: end-to-end suture repair when the laceration is repairable, and nerve graft when it is not
- Patients >18 years: end-to-end suture repair when the laceration is repairable and has presented within 6 months, and tendon transfer when these criteria have not been met5
Nerve Transfers21
- Nerve transfer for brachial plexus reconstruction are well defined in the literature; however, their usefulness for reconstructing median nerve lacerations is still evolving.1 However, nerve transfer(s) have been gaining in popularity as an alternative to tendon transfers/nerve grafting for patients with severe proximal nerve injuries, but the field is still evolving with new techniques being described as microsurgical techniques improve and more patients experience good outcomes.
- Proposed Advantages of Nerve Transfer
- Able to also restore sensory function
- Multiple muscle groups can be reinnervated with a single nerve transfer
- Muscle origin/insertions are not disrupted
- Principles of Nerve Transfer
- Ideally pick a donor nerve near the motor endplates of the target muscle to minimize time to innervation. A shorter distance means shorter time for reinnervation
- Use expendable or redundant nerve fibers
- Use donors that have a large number of axons
- Use donors that already innervate synergistic muscles with the target muscle (helps facilitate re-education)
- Using donors that match the target is ideal, i.e. motor donors for motor targets, sensory donors for sensory targets
- Re-innervation after 12-18 months may be impossible, as prolonged denervation will cause muscle cell death and fibrosis.
- Nerve transfers for Radial Nerve Palsy
- Goals: Restore wrist extension, finger extension, radial sensation
- Often augmented with pronator teres to ECRB tendon transfer (allows for wrist extension while nerve recovers)
- Fascicles of Median nerve to FCR, PL or FDS are transferred to the PIN and the branch of the radial nerve innervating ECRB. The strongest donor should be used to restore ECRB function
- Radial sensory branch may be coapted end to side to the median nerve in an attempt to restore sensation