Results of Intercostal Nerve Transfer to the Musculocutaneous Nerve in Brachial Plexus Birth Palsy

Background: Intercostal nerve (ICN) transfer has been one of the main extraplexal nerve transfers in treating brachial plexus root avulsion. This retrospective study evaluated results of ICN transfer for reconstruction of the musculocutaneous nerve (MCN) in brachial plexus birth palsy (BPBP). Methods: Eighteen boys and 6 girls with BPBP, who had avulsion of at least 2 spinal nerves of the plexus, underwent ICN transfer for reconstruction of MCN, from March 2003 to October 2005. The brachial plexus lesion was diagnosed by clinical assessment, surgical exploration, and intraoperative neurophysiological investigations. The age at surgery ranged from 3 to 11 months of life, with a mean of 5 months. Two intercostals were used for one, 3 intercostals for 9, and 4 intercostals for 14 patients. The intercostals were transferred to MCN in 12 and to the anterior division of the upper trunk in the other 12 cases. Results: Twenty-four children were followed up for 24 to 79 months, with an average of 53 months. No complications were found in the respiratory system. Of 14 transfers with 4 intercostals, biceps gained M4 strength in 8, M3 in 4, and M2 in 2. Of 9 transfers with 3 intercostals, biceps obtained M4 strength in 8 and M3 in 1. One transfer with 2 intercostals got M4 strength of biceps. Twelve patients whose intercostals were transferred to MCN, gained M4 strength of biceps in 11 and M3 in 1, whereas the other 12 patients with intercostals transferred to anterior division of the upper trunk, obtained M4 strength of biceps in 6, M3 in 4, and M2 in 2. The rate of M3 strength or more was 92% and that of M4 was 71%. Conclusions: ICN transfer is a safe and reliable procedure for reconstruction of the MCN in BPBP. There seems to be no difference of effects between transfers with 3 and those with 4 intercostals. The transferred nerves should be coapted to MCN, rather than a more proximal portion of the plexus.