OnabotulinumtoxinA injection as an adjunct in the treatment of posterior shoulder subluxation in neonatal brachial plexus palsy

Background: Botulinum toxin A is used to treat contractures in children with spasticity by temporarily interfering with neural transmission at the motor end plate. In infants with brachial plexus palsy, posterior shoulder subluxation and dislocation are the result of muscle imbalance, in which neurologic recovery is evolving, and spasticity is not a deforming force. We postulated that temporary weakening of the shoulder internal rotator muscles with botulinum toxin A would facilitate reduction of the glenohumeral joint in such infants with early posterior shoulder subluxation or dislocation. Methods: Thirty-five infants with posterior subluxation or dislocation of the shoulder due to brachial plexus palsy were treated with botulinum toxin A between January 1999 and December 2006, and were followed for a minimum period of one year. Records were reviewed for the severity of the palsy, age at time of treatment, recurrence of subluxation or dislocation, and the subsequent need for further treatment to reduce the glenohumeral joint. Results: The average age at the time of shoulder reduction and botulinum toxin-A injection was 5.7 months. Six patients had a second injection. Reduction of the shoulder was maintained in twenty-four (69%) of the thirty-five patients. There were no complications related to the use of botulinum toxin A. Conclusions: Although there may be specific risks associated with its use, botulinum toxin-A injection into the internal rotator muscles is a useful adjunct to the treatment of early posterior subluxation or dislocation of the shoulder in infants with neonatal brachial plexus palsy, and may help to avoid the need for open surgical procedures to restore or maintain shoulder reduction. Level of Evidence: Therapeutic Level IV. See Instructions to Authors for a complete description of levels of evidence.