Permanent Erb palsy: a traction-related injury?

Historically, the primary risk factor attributed to brachial plexus injury during birth has been excessive traction applied at delivery to an entrapped anterior shoulder. However, recent evidence has suggested that not all cases of brachial plexus palsy are attributable to traction. We have encountered several cases of permanent Erb palsy associated with birth that were not attributable to traction applied at delivery. We reviewed cases of neonates with documented permanent Erb palsy that occurred either in the absence of shoulder dystocia or in the neonate's posterior arm in the presence of anterior shoulder dystocia. We identified four cases that occurred in the absence of shoulder dystocia and four cases that occurred in the posterior arm of infants with anterior shoulder dystocia. These data further support the notion that the etiology of permanent brachial plexus palsy associated with birth may not be related to traction.