Pronator Quadratus to Extensor Carpi Radialis Brevis Nerve Transfer in C5-C7 or C5-C8 Brachial Plexus Injuries for Independent Wrist Extension

Transfer of extensor carpi radialis brevis branch of radial nerve to anterior interosseous nerve for lower trunk brachial plexopathy after motor vehicle accident

The patient is a 15-year-old male who sustained injury to his right lower brachial plexus (C8-T1) in a motor vehicle accident. Six months after the injury, the patient still had persistent hand weakness and wished to regain function in his first and second digits. Transfer of the extensor carpi radialis brevis (ECRB) branch of the radial nerve to the anterior interosseous nerve (AIN) was performed to restore motor function. The patient did well after the surgery, although it may take 12-24 months for benefits to fully manifest. Pertinent surgical anatomy and techniques are highlighted in this video demonstration. The video can be found here: https://stream.cadmore.media/rr10.3171/2022.10.FOCVID2287.

Plasticity of the Central Nervous System Involving Peripheral Nerve Transfer

Peripheral nerve injury can lead to partial or complete loss of limb function, and nerve transfer is an effective surgical salvage for patients with these injuries. The inability of deprived cortical regions representing damaged nerves to overcome corresponding maladaptive plasticity after the reinnervation of muscle fibers and sensory receptors is thought to be correlated with lasting and unfavorable functional recovery. However, the concept of central nervous system plasticity is rarely elucidated in classical textbooks involving peripheral nerve injury, let alone peripheral nerve transfer. This article is aimed at providing a comprehensive understanding of central nervous system plasticity involving peripheral nerve injury by reviewing studies mainly in human or nonhuman primate and by highlighting the functional and structural modifications in the central nervous system after peripheral nerve transfer. Hopefully, it will help surgeons perform successful nerve transfer under the guidance of modern concepts in neuroplasticity.

Reconstruction of C5-C8 (T1 Hand) Brachial Plexus Paralysis in a Series of 52 Patients

PURPOSE

A C5-C8 brachial plexus root injury, also known as a T1 hand, is associated with paralysis of shoulder abduction or external rotation and elbow flexion, accompanied by variable elbow, wrist, thumb, or finger extension deficits. We report the results of reconstruction for C5-C8 brachial plexus paralysis in 52 patients operated upon within 12 months of injury and having at least 24 months of follow-up.

METHODS

We considered surgery to be indicated if, by the fifth month after trauma, shoulder abduction and external rotation and elbow flexion remained paralyzed. Root grafting was possible in 35% of the patients and was performed concomitantly with nerve transfers. Shoulder motion was reconstructed by transferring the spinal accessory to the suprascapular nerve. Elbow flexion was restored by transferring fascicles from either the median or ulnar nerve to the biceps motor branch. When needed, elbow extension was reconstructed by transferring 1 motor branch of the flexor carpi ulnaris to the triceps lower medial head motor branch. Wrist extension was restored by transferring the distal anterior interosseous nerve to the extensor carpi radialis brevis motor branch.

RESULTS

Within 12 months of injury, we observed preserved or spontaneous recovery of elbow, wrist, finger, and thumb extension in 25%, 12%, 50%, and 68% of patients, respectively. After surgical reconstruction, improved range of motion for shoulder, elbow flexion, and wrist extension scoring at least M3 was present in 90% of our patients. All 10 patients in whom a motor branch of the flexor carpi ulnaris was used for triceps reconstruction recovered elbow extension, while flexor carpi ulnaris function was preserved.

CONCLUSIONS

In approximatively 90% of our patients, distal nerve transfers resulted in functional recovery of shoulder abduction, elbow flexion or extension, and wrist extension.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic IV.