The Medial Cord –Anterior Upper Trunk (MC-aUT) Nerve Transfer in Brachial Plexus Injuries. Technique and Results

Research Article

Austin Neurosurg Open Access. 2017; 4(1): 1055.

The Medial Cord –Anterior Upper Trunk (MC-aUT) Nerve Transfer in Brachial Plexus Injuries. Technique and Results

Ferraresi S*, Basso E, Maistrello L, Lucchin F and Di Pasquale P

Department of Neurosurgery, Ospedale Santa Maria della Misericordia, Italy

*Corresponding author: Stefano Ferraresi, Head Department of Neurosurgery, Ospedale Santa Maria della Misericordia, Rovigo, Italy

Received: February 21, 2017; Accepted: April 19, 2017; Published: April 26, 2017


Aim of this paper is to report on a technical variant of the Medial Cord to the Musculocutaneous (MCMc) nerve transfer. The MCMc is a new type of neurotization that we described in 2014, capable of reanimating the elbow flexion in multilevel avulsive injuries of the upper and middle plexus.

In the over mentioned procedure the reinnervation of the musculocutaneous nerve is obtained via a nerve transfer from the medial cord. The selected fascicles are those directed principally to the flexor carpi radial is, ulnaris, and to a lesser degree the flexor digitorum profundus.

They are located in the inverted V-shaped bifurcation between the internal contribution of the median nerve and the ulnar nerve.

The results of this technique are excellent. There are no failures and no complications when the hand shows a normal wrist and finger flexion and a normal intrinsic function, namely in C5-C6 or C5-C6-C7 avulsive injuries of the brachial plexus.

However, the sole problem appears with an agenesia of the musculocutaneous nerve (4% of our series).

In these patients, the lateral cord tapers directly into the median nerve one or more branches entering directly the biceps and the brachialis muscles at the upper third of the arm. This arrangement is hostile to the MCMc nerve transfer so as it was originally conceived.

The present paper reports the results of a technical variant of the MCMc technique, namely the targeting, as recipient, of the anterior contribution of the upper trunk, cut and rerouted under the clavicle to reach the donor medial cord.

Keywords: Brachial plexus; Nerve transfer; Musculocutaneous nerve; Biceps muscle; Brachialis muscle; Root avulsion


Since the onset of the microsurgical era of brachial plexus repair [1,2], until the early nineties [3-7] the treatment of an avulsive injury of C5-C6 or of C5-C6-C7 was a great challenge for the microsurgeon.

Several techniques had been attempted over the years to restore elbow flexion but none of them [8-12] with the exception of the medial pectoral nerves [13-16] offered a constant and reliable muscle power. The lower pectoral nerves, however, are available in number of two and, when used both, entailed a remarkable loss of strength in the pectoralis major. Moreover, the feasibility of their use as a direct nerve transfer is unpredictable, since from time to time they require short grafts. The extraplexual donors, namely the phrenic nerve [17,18], the accessory nerve [19-26] the intercostals nerves [27-37] the motor cervical rami [38,39] and the hypoglossal nerve [40,41] were also variably used to restore elbow flexion but none of them can count on constant and reproducible results. So, in spite of the presence of a normal hand function, this kind of lesions rather often ended with a heavily disabled arm due to a poor quality of recovery in the biceps-brachialis complex.

The typical patient had great difficulty in lifting even moderately heavy objects and the condition was futherly worsened by an unstable shoulder due to the denervation of the rhomboids and serratus anterior muscles.

In 1993 and 1994 the pioneering work of C. Oberlin [42] announced a true revolution in the treatment of C5-C6 avulsive injuries of the brachial plexus. In his original paper he described a successful selective reinnervation of the biceps branches via a fascicular neurotization from the ulnar nerve. However, his merit went far beyond the pure technique he described. He opened in various directions the mind of the microsurgeons, showing to the scientific world that a neurotization from fascicles of a sound nerve yielded results better than ever and without threatening the overall function of the donor.

This gave rise to the by-pass or nerve transfer era [43,44], which has been, by far, the recent major advance in the field of brachial plexus reconstructive surgery. Many different ingenious transfers are currently used by the microsurgeons [3,5,45-61] and the direct reinnervation (without interposition of grafts) of the paralyzed nerves with motor branches coming from an intact part of the brachial plexus has gained worldwide acceptance.

Among the available techniques, the Authors have recently published (2014) an original technique, called the MCMc nerve transfer [48], which has shown constant, reproducible and, so far, unparalleled results on biceps and brachialis muscle recovery.

With this technique the entire plexus is, as always, explored via the combined supraclavicular and infraclavicular approach. The philosophy is to assess the level and the entity of the damage to exclude an unexpected integrity of the upper plexus and check for a possible two-stage distal lesion of the musculocutaneous and the axillary nerves.

The musculocutaneous nerve is cut at its exit from the lateral cord and reinnervated via one or two fascicles aimed at the flexor carpi radialis or ulnaris, usually selected from the medial contribution of the median nerve at the division with the ulnar nerve (Figure 1).