The four patterns of nerve injury in Erbs Palsy include:
This is characterized by injury to nerves as a result of over- stretching of nerve roots in the setting of shoulder dystocia (reported mostly in the delivery of mal-positioned baby like delivery of baby in breech position). The nerve may be bruised or shows signs of inflammatory swelling but no other form of injury will be seen. In most cases, nerves may recover spontaneously within 3 to 4 months after birth.
This pattern of nerve injury is less common and is associated with much severe birth trauma. The tearing of nerve fibers occurs outside the spinal cord that may require surgical repair. Most cases are associated with a favorable prognostic course if treatment is attempted early.
This is regarded as the most severe pattern of nerve root injury that is characterized by rupture of nerve root at the level of spinal cord. It constitutes no more than 15 to 20% of all the cases. Most cases are refractory to surgical treatment by repair of torn nerve itself and management of avulsion is managed by surgical replacement of affected tendons when the child is 2 or 3.
In some cases, injured nerves develop scar tissue around nerve fibers during the repair process that may interfere with normal neuronal functioning. This may result in weakness of muscles, numbness or paresthesia depending upon the component of nerve root involved. Treatment modalities focus mainly at removing the scar tissue to allow proper healing of nerve. Other options that may be considered are nerve reconstruction and/ or tendon transfers.
Research data indicates that besides nature and pattern of injury, type of treatment modality employed greatly determine prognosis. Even with severe nerve injury and well- developed complications, if appropriate intervention is performed, results are usually promising. For example the most common permanent deformity in babies born with Erbs Palsy is internal rotation contracture that responds very well to surgical intervention. The results of a study presented in The Journal of Hand Surgery (1) indicate that the osteotomy performed in 15 children resulted in the improvement of arm extension and shoulder abduction along with internal and external rotation of the upper limb.
1. Al-Qattan, M. M. (2002). Rotation osteotomy of the humerus for Erb's palsy in children with humeral head deformity. The Journal of hand surgery, 27(3), 479-483.
2 "Types of Nerve Injuries Relating to Erb's Palsy." Types of Nerve Injuries Relating to Erb's Palsy. N.p., n.d. Web. 15 June 2013.. http://www.erbpalsy.org/types.html