Nerve transfer in the spastic upper limb: anatomical feasibility study.

Area of Science:

• Neurosurgery
• Orthopedic Surgery
• Reconstructive Surgery

Background:

• Nerve transfers are established treatments for upper limb paralysis, particularly for brachial plexus injuries.
• Current applications include evaluation for tetraplegia, but not yet for spastic upper limbs.
• Spastic upper limb deformities involve overactive flexors/pronators and weak extensors/supinators.

Purpose of the Study:

• To investigate the anatomical feasibility of a novel nerve transfer technique for spastic upper limbs.
• To combine selective neurectomy with nerve transfer, moving a motor branch from a spastic elbow flexor to a paralyzed wrist extensor.
• Hypothesized that this would decrease elbow flexor spasticity while activating wrist extensors.

Main Methods:

• Ten cadaveric dissections were performed to assess the anatomical viability of the proposed nerve transfer.
• Key measurements included nerve emergence, length, muscle entry point, and diameter.
• The transfer of a motor branch from the brachioradialis (BR) to the extensor carpi radialis longus (ECRL) or brevis (ECRB) was attempted.

Main Results:

• Multiple motor nerves were identified for the brachioradialis (BR) (1-4) and extensor carpi radialis longus (ECRL) (1-2).
• The nerve transfer from BR to ECRL was anatomically achievable in all specimens, allowing for satisfactory coaptation.
• The nerve branch to the extensor carpi radialis brevis (ECRB) emerged too distally for successful anastomosis.

Conclusions:

• Nerve transfers from the brachioradialis (BR) to the extensor carpi radialis longus (ECRL) are anatomically feasible.
• This technique presents a potential new therapeutic strategy for managing spasticity in the upper limbs.
• Further research may validate this approach for clinical application in patients with spastic upper limb deformities.