NERVE TRANSFERS IN BRACHIAL PLEXUS INJURIES SURGERY

Abstract

Nerve transfers (previously called neurotization) involve the repair of a distal denervated nerve element by using a proximal foreign nerve as the donor of neurons and their axons to reinnervate the distal targets. The concept is to sacrifice the function of a lesser-valued donor muscle to revive function in the recipient nerve and muscle that will undergo reinnervation. Adult traumatic brachial plexus injuries can have devastating effects on upper extremity function. Although neurolysis, nerve repair, and nerve grafting have been used to treat injuries to the plexus, nerve transfer makes use of an undamaged nerve to supply motor input over a relatively short distance to reinnervate a denervated muscle. The use of nerve transfers has greatly increased surgical options for children who have brachial plexus birth palsies. Nerve transfers have considerable advantages, including easier surgical techniques, avoidance of neuroma resection, and direct motor and sensory reinnervation. Nerve transfer is classified into four methods in the brachial plexus reconstruction: extraplexus neurotization, intraplexus neurotization, close-target neurotization, and end-to-side neurotization. The choice of nerve transfers appears to be surgeon biased. Some surgeons prefer one technique over the other option, based on their experience, results, and familiarity. In cases with multiple root avulsions, the available donor axons are insufficient so contralateral C7 root transfer to two different recipient nerves is a feasible and effective approach. Reconstruction for shoulder function is critical because external rotation of the shoulder allows elbow flexion through a full functional range. The aim of nerve transfer is to reconstruct the axillary nerve with radial nerve branch to medial head of triceps and to reconstruct the suprascapular nerve with the spinal accessory nerve. Reconstructive priority after brachial plexus injury is to restore elbow flexion. This is achieved by reconstruction of the biceps branch and the brachialis branch of the musculocutaneous nerve with redundant donor fascicles from the ulnar and median nerves. Phrenic and intercostal nerves transfer is avoided in infants because the diaphragm is not yet firmly fixed to the vertebral bodies and severe respiratory problems can occur. However, there was no evidence that phrenic and intercostal nerves transfer leads to a significant reduction in respiratory function in adults. Cortical mapping and relearning are key factors in optimizing patient outcome following motor nerve transfers. To maximize function following nerve transfers, the rehabilitation program must include motor reeducation to initiate recruitment of the weak reinnervated muscles and to establish new motor patterns and cortical mapping. Patient education and a home program are essential to obtain the optimal functional result.