Brachial plexus birth injury: classification, natural history and shoulder external rotation.

There is significant interest in research on the pathology, natural history and treatment of brachial plexus birth injury. This article comments on a few newly published papers in the Journal of Hand Surgery (European Volume) to highlight updates and new research. Classification of brachial plexus birth injury remains challenging. Intraoperative findings from a recent article allow the introduction of a new classification based on findings during surgical exploration, providing a more precise description of the extent and severity of injury. The classification correlates well with pre- and postoperative function and should allow more accurate comparisons of treatment outcomes. Knowledge of the natural history of brachial plexus birth injury can help guide management decisions, such as the proportion of patients who will spontaneously recover active shoulder abduction. In another recent article, almost all cases regained 90° or more abduction, indicating a good chance of a satisfactory function. However, in contrast to other studies, recovery of elbow flexion at age 4 months did not predict outcome. Shoulder external rotation is an important movement which often recovers poorly after brachial plexus birth injury. A third article reported no difference in long-term outcomes of nerve grafting or transfer for restoration of shoulder external rotation. Overall, about a third of children did not regain active external rotation, indicating the difficulties restoring this movement. These studies contribute to improving management of brachial plexus birth injury, but more investigation of both the natural history and treatment outcomes is needed.