Neonatal palsy is a traction injury to the brachial plexus that usually occurs during delivery. Risk factors include shoulder or fetal dystocia, obesity, and prolonged difficult labor. Despite improvements in obstretrical practices, the incidence of this palsy has not declined because of increases in birth weight and maternal obesity.
Recovery depends upon severity. Overall, about half spontaneously completely resolve during the first year. Most improvement occurs in the first 3 months. Poor prognostic signs include the presence of a Horner syndrome, total plexus involvement, and a failure of return of function. Failure of recovery of elbow flexion by 3–6 months or, more accurately, failure of recovery of elbow flexion, wrist, and digital extension by 4 months correlates with a poorer prognosis. Common residual disabilities include loss of external rotation and abduction and shoulder subluxation.
Note the resting position and spontaneous movement of each joint of the upper limb. Evaluate for Horner syndrome, and assess the range of passive and active joint motion.
Anatomic classification Severity is determined by the nature and extent of the lesion. Mild lesions are stretch injuries of C5–C6. Severe injuries involve avulsion of nerve roots over multiple levels down to T1.
Residual deformity Use the modified Mallet classification. Five functions are assessed: hand-to-mouth, hand-to-neck, hand-to-spine, global abduction, global external rotation. Each is graded from 1 to 4.
Treatment of Neonatal Brachial Plexus Palsy
Several forms of management may be useful.
Range of motion Maintain joint mobility with passive rotation of the shoulder (especially external rotation), elbow, and wrist. Instruct parents how to gently range these joints with each diaper change.
Brachial plexus exploration Evaluate those with severe injuries by CT and MRI studies. Plexus repairs are controversial, as results are unpredictable and should not compromise later reconstructive procedures. Consider early exploration in the first 3 months if Horner sign and a flail limb are present. Repairs of avulsion injuries are most uncertain and require transfers of intercostal or pectoral nerves. Direct nerve repairs are usually impossible, and sural nerve grafts to bridge a defect are needed. Reconstruction may again be considered between 4 to 6 months for less severe but persisting palsies.
Shoulder dysplasia Children with residual muscle imbalance often develop progressive glenoid hypoplasia and an increasing posterior subluxation of the humeral head. Monitor by sonography. In some, Botox may be helpful in reducing muscle imbalance to protect the joint from increasing dysplasia.
Muscle procedures are indicated for children with disabling adduction and internal rotation contractures. The most common procedure is the Sever-L’Episcopo transfer. This procedure includes release of the pectoralis major, subscapularis, and joint capsule if contracted. Axillary nerve palsy is a potential complication. This procedure is usually performed in early childhood.
Rotational humeral osteotomy is indicated for an internal rotation deformity that limits function. Delay the procedure until mid or late childhood. Rotate the humerus to provide about equal internal and external rotation. Results are predictable, correction is usually permanent, and complications are infrequent.