The medial cord to musculocutaneous (MCMc) nerve transfer: a new method to reanimate elbow flexion after C5-C6-C7-(C8) avulsive injuries of the brachial plexus--technique and results

Neurosurg Rev. 2014 Apr;37(2):321-9; discussion 329. doi: 10.1007/s10143-014-0522-1. Epub 2014 Feb 14.

Abstract

The aim of this paper is to report on our ample experience with the medial cord to musculocutaneous (MCMc) nerve transfer. The MCMc technique is a new type of neurotization which is able to reanimate the elbow flexion in multilevel avulsive injuries of the brachial plexus provided that at least the T1 root is intact. A series of 180 consecutive patients, divided into four classes according to the quality of hand function, is available for a long-term follow-up after brachial plexus surgery. The patients enrolled for the study have in common a brachial plexus palsy showing multiple cervical root avulsive injuries at two (C5-C6), three (C5-C6-C7) and four (C5-C6-C7-C8) levels. The reinnervation of the musculocutaneous nerve is obtained via an end-to-end transfer from two donor fascicles located in the medial cord. The selected fascicles are those directed principally to the flexor carpi radialis, ulnaris and, to a lesser degree, the flexor digitorum profundus. Under normal anatomic conditions, they are located in the medial cord, and their site corresponds to the inverted V-shaped bifurcation between the internal contribution of the median nerve and the ulnar nerve. The technique has no failure and no complications when the hand shows a normal wrist and finger flexion and a normal intrinsic function. In case of suboptimal conditions of the hand, the technique has proved technically more challenging, but still with 67% satisfactory results. In the four-root avulsive injuries, however, this method shows its limitations and an alternative strategy should be preferred when possible. EMG analysis shows a reinnervation in both the biceps and the brachialis muscles, explaining the high quality of the observed results. Moreover, this technique theoretically offers the possibility of a "second attempt" at a more distal level in case of failure of the first surgery. This procedure is quick, safe, extremely effective and easily feasible by an experienced plexus surgeon. The ideal candidate is a patient harbouring a C5-C6 avulsive injury of the upper brachial plexus with a normally functioning hand.

MeSH terms

  • Aged
  • Brachial Plexus / surgery*
  • Brachial Plexus Neuropathies / surgery*
  • Elbow / innervation
  • Elbow / surgery*
  • Elbow Joint / innervation
  • Elbow Joint / surgery*
  • Electromyography
  • Female
  • Follow-Up Studies
  • Humans
  • Male
  • Middle Aged
  • Nerve Transfer* / methods
  • Treatment Outcome
  • Ulnar Nerve / physiopathology
  • Ulnar Nerve / surgery