Brachial plexus birth palsy can result in permanent lifelong deficits and unfortunately continues to be relatively common despite advancements in obstetric care. The diagnosis can be made shortly after birth by physical examination, noting a lack of movement in the affected upper extremity. Treatment begins with passive range-of-motion exercises to maintain flexibility and tactile stimulation to provide sensory reeducation. Primary surgery consists of microsurgical nerve surgery, whereas secondary surgery consists of alternative microsurgical procedures, tendon transfers, or osteotomies, all of which improve outcomes in the short term. However, the long-term outcomes of current treatment recommendations remain unknown.
Key points
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Brachial plexus birth palsies occur in varying degrees and can have lifelong physical and psychological impact for patients as well as their families.
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The best method for diagnosing and following infants with brachial plexus birth palsy is serial physical examinations.
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Muscular balance about the shoulder is critical for external rotation and internal rotation to promote the development of a normal glenohumeral joint and to perform activities of daily living.
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Assessment of midline function is crucial to assess the amount of internal rotation necessary to perform activities of daily living, such as zippering and buttoning.
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When performing procedures to improve external rotation, it is imperative to make sure midline function is preserved.
Introduction
Brachial plexus birth palsy is a common injury affecting 1 to 4 children per 1000 live births. This incidence seems to be increasing, due to increasing birth weights, despite advancements in obstetric care. Fortunately, most affected infants have spontaneous recovery within the first 6 to 8 weeks of life and therefore progress to obtain normal or near normal range of motion and strength. However, if substantial recovery is not present by 3 months of age, permanent range of motion limitations, decreased strength, and decreased size and girth of the affected limb will be present.
Only half of infants affected with a brachial plexus birth palsy have at least one known risk factor. These risk factors include large babies (macrosomia), prolonged labor, shoulder dystocia, instrumented delivery (vacuum and/or forceps), multiparous pregnancies, previous deliveries resulting in brachial plexus birth palsy, gestational diabetes, and fetal distress that is thought to result in relative hypotonia. In addition, new research has shown that tachysystole, defined as greater than 6 contractions in 10 minutes or one large contraction lasting more than 2 minutes, and the utilization of oxytocin are also risk factors for an infant sustaining a brachial plexus birth palsy (Mehlmann and colleagues, American Academy of Orthopedic Surgery, San Francisco, CA, February 2012). Breech positioning was once thought to be a risk factor, but more recently this notion has been contradicted. Protective factors include twin or multiple birth mates and delivery via Cesarean section; however, these factors do not eliminate the risk completely ( Box 1 ).
Large babies (macrosomia)
Prolonged labor
Shoulder dystocia
Instrumented delivery (vacuum and/or forceps)
Multiparous pregnancies
Previous deliveries resulting in brachial plexus birth palsy
Gestational diabetes
Fetal distress that is thought to result in relative hypotonia
Tachysystole (defined as greater than 6 contractions in 10 minutes or one large contraction lasting more than 2 minutes)
Utilization of oxytocin
Anatomy
The brachial plexus provides all sensory and motor innervation for the upper extremity. A “normal” anatomic pattern is seen in 75% of the population, in which the ventral rami of the C5-T1 nerve roots form the brachial plexus. An additional contribution from the C4 nerve root, known as a prefixed cord, occurs in 22% of the population, whereas a postfixed cord, a contribution from the T2 nerve root, occurs in 1% of the population.
The roots of the brachial plexus combine to form the 3 trunks of the brachial plexus, termed the upper, middle, and lower trunks. Each trunk divides into an anterior and posterior division and these divisions combine to make the cords of the brachial plexus, termed the lateral, posterior, and medial cords, based on their relationship to the axillary artery. The terminal branches of the brachial plexus stem from the cords and consist of the 5 major peripheral nerves in the upper extremity: the axillary, the musculocutaneous, the median, the ulnar, and the radial nerves. Multiple smaller branches arise from the various portions of the plexus, except the divisions, that provide additional amounts of motor and/or sensory innervation.
Diagnosis
Patients with brachial plexus birth palsy are typically diagnosed shortly after birth due to a lack of movement about the shoulder, elbow, wrist, and/or digits. Obtaining a thorough birth history to assess for risk factors as well as to learn the APGAR scores is necessary, because children with brachial plexus birth palsy may have experienced cerebral anoxia during the delivery process. Subsequently, direct visualization of the child will provide substantial information regarding the extent of injury.
The newborn physical examination is diagnostic. Tactile stimulation is used in an attempt to encourage the infant to move the limb. In addition, the neonatal reflexes can be assessed. A sudden extension of the neck causing the shoulders to abduct, the elbows to extend, and the fingers to extend and spread is known as the Moro reflex. Turning the infant’s head to the side with the arm and leg extending on the side the head is turned to is known as the asymmetric tonic neck reflex. Usually, the contralateral arm and leg flex, creating a position in which the infant looks like he/she is a fencer. Assessment for Horner syndrome is also performed by looking for ptosis, miosis, and/or anhydrosis, which if present indicates lower root involvement and implies a poor prognosis.
The newborn physical examination should also assess, via palpation, for a clavicle or humerus fracture, which may coexist with a brachial plexus birth palsy or cause a pseudopalsy, as the infant resists movement secondary to pain. The presence of spasticity during the examination may indicate the infant having a period of cerebral anoxia during the delivery. Concomitant brachial plexus birth palsy and cerebral palsy can occur in the unfortunate infant.
Once a diagnosis is established, serial examinations are needed to predict recovery and if additional interventions are needed. Ideally, the initial extent of nerve injury is accurately noted so that subsequent recovery can be assessed, as this is crucial when deciding surgical intervention.
Utilization of additional radiologic or electrodiagnostic studies is somewhat controversial because a good physical examination provides the necessary information and none of the modalities can uniformly predict the exact nerve injury pattern. However, radiologic studies that demonstrate nerve root avulsions (preganglionic injuries) are helpful with regard to preoperative planning. Computed tomography myelography and magnetic resonance imaging have greater than 90% true positive rates for determining avulsion injuries correlated at surgery when large diverticula or frank myelomeningoceles are seen. Electrodiagnostic studies, including nerve conduction velocity and needle electromyography, overestimate clinical recovery in the proximal muscles of the shoulder and arm. This incorrect prediction may provide false hope to the parents and delay referral for surgical intervention.
Introduction
Brachial plexus birth palsy is a common injury affecting 1 to 4 children per 1000 live births. This incidence seems to be increasing, due to increasing birth weights, despite advancements in obstetric care. Fortunately, most affected infants have spontaneous recovery within the first 6 to 8 weeks of life and therefore progress to obtain normal or near normal range of motion and strength. However, if substantial recovery is not present by 3 months of age, permanent range of motion limitations, decreased strength, and decreased size and girth of the affected limb will be present.
Only half of infants affected with a brachial plexus birth palsy have at least one known risk factor. These risk factors include large babies (macrosomia), prolonged labor, shoulder dystocia, instrumented delivery (vacuum and/or forceps), multiparous pregnancies, previous deliveries resulting in brachial plexus birth palsy, gestational diabetes, and fetal distress that is thought to result in relative hypotonia. In addition, new research has shown that tachysystole, defined as greater than 6 contractions in 10 minutes or one large contraction lasting more than 2 minutes, and the utilization of oxytocin are also risk factors for an infant sustaining a brachial plexus birth palsy (Mehlmann and colleagues, American Academy of Orthopedic Surgery, San Francisco, CA, February 2012). Breech positioning was once thought to be a risk factor, but more recently this notion has been contradicted. Protective factors include twin or multiple birth mates and delivery via Cesarean section; however, these factors do not eliminate the risk completely ( Box 1 ).
Large babies (macrosomia)
Prolonged labor
Shoulder dystocia
Instrumented delivery (vacuum and/or forceps)
Multiparous pregnancies
Previous deliveries resulting in brachial plexus birth palsy
Gestational diabetes
Fetal distress that is thought to result in relative hypotonia
Tachysystole (defined as greater than 6 contractions in 10 minutes or one large contraction lasting more than 2 minutes)
Utilization of oxytocin
Anatomy
The brachial plexus provides all sensory and motor innervation for the upper extremity. A “normal” anatomic pattern is seen in 75% of the population, in which the ventral rami of the C5-T1 nerve roots form the brachial plexus. An additional contribution from the C4 nerve root, known as a prefixed cord, occurs in 22% of the population, whereas a postfixed cord, a contribution from the T2 nerve root, occurs in 1% of the population.
The roots of the brachial plexus combine to form the 3 trunks of the brachial plexus, termed the upper, middle, and lower trunks. Each trunk divides into an anterior and posterior division and these divisions combine to make the cords of the brachial plexus, termed the lateral, posterior, and medial cords, based on their relationship to the axillary artery. The terminal branches of the brachial plexus stem from the cords and consist of the 5 major peripheral nerves in the upper extremity: the axillary, the musculocutaneous, the median, the ulnar, and the radial nerves. Multiple smaller branches arise from the various portions of the plexus, except the divisions, that provide additional amounts of motor and/or sensory innervation.
Diagnosis
Patients with brachial plexus birth palsy are typically diagnosed shortly after birth due to a lack of movement about the shoulder, elbow, wrist, and/or digits. Obtaining a thorough birth history to assess for risk factors as well as to learn the APGAR scores is necessary, because children with brachial plexus birth palsy may have experienced cerebral anoxia during the delivery process. Subsequently, direct visualization of the child will provide substantial information regarding the extent of injury.
The newborn physical examination is diagnostic. Tactile stimulation is used in an attempt to encourage the infant to move the limb. In addition, the neonatal reflexes can be assessed. A sudden extension of the neck causing the shoulders to abduct, the elbows to extend, and the fingers to extend and spread is known as the Moro reflex. Turning the infant’s head to the side with the arm and leg extending on the side the head is turned to is known as the asymmetric tonic neck reflex. Usually, the contralateral arm and leg flex, creating a position in which the infant looks like he/she is a fencer. Assessment for Horner syndrome is also performed by looking for ptosis, miosis, and/or anhydrosis, which if present indicates lower root involvement and implies a poor prognosis.
The newborn physical examination should also assess, via palpation, for a clavicle or humerus fracture, which may coexist with a brachial plexus birth palsy or cause a pseudopalsy, as the infant resists movement secondary to pain. The presence of spasticity during the examination may indicate the infant having a period of cerebral anoxia during the delivery. Concomitant brachial plexus birth palsy and cerebral palsy can occur in the unfortunate infant.
Once a diagnosis is established, serial examinations are needed to predict recovery and if additional interventions are needed. Ideally, the initial extent of nerve injury is accurately noted so that subsequent recovery can be assessed, as this is crucial when deciding surgical intervention.
Utilization of additional radiologic or electrodiagnostic studies is somewhat controversial because a good physical examination provides the necessary information and none of the modalities can uniformly predict the exact nerve injury pattern. However, radiologic studies that demonstrate nerve root avulsions (preganglionic injuries) are helpful with regard to preoperative planning. Computed tomography myelography and magnetic resonance imaging have greater than 90% true positive rates for determining avulsion injuries correlated at surgery when large diverticula or frank myelomeningoceles are seen. Electrodiagnostic studies, including nerve conduction velocity and needle electromyography, overestimate clinical recovery in the proximal muscles of the shoulder and arm. This incorrect prediction may provide false hope to the parents and delay referral for surgical intervention.
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