BRACHIAL PLEXUS BIRTH PALSY

The brachial plexus is a network of nerves connecting the spine at the base of the neck to the shoulders and upper extremities. Brachial plexus birth palsy (BPBP) is upper-limb paralysis in a newborn owing to injury to one or more nerve roots of the brachial plexus. The most prevalent form is Erb’s palsy, whereby movements around the shoulder and flexion at the elbow are impaired due to injury to C5-C6 nerve roots. Total BPBP occurs when nerve roots from C5-T1 are injured, thereby impairing all movement and sensation in shoulders, arms, elbow, wrist, and fingers. In most cases, injuries are transient and recover spontaneously within 1 month to 2 years; however, ~27-35% of BPBP cases may develop permanent upper-extremity paralysis. Prognosis depends on the severity and location of the injury.

Pathophysiology

• Maternal
• Gestational diabetes
• Excessive weight gain
• Uterine anomalies such as fibroma and bicornuate uterus
• History of BPBP during a previous birth
• Macrosomia (birth weight >4 kg)
• Decreased fetal arm movements
• First cervical rib and clavicular fracture
• Shoulder dyscotia (increases risk by 100 times)
• Birth injury to humerus
• Instrumented delivery
• Tachysystole (> 6 contractions in 10 min or 1 large contraction lasting >2 min)
• Use of oxytocin
• Short second stage of labor
• Ventral nerve roots C5-C8 and T1, originating from C5, C6, C7, and T1 vertebrae
• Depending on the nerve roots injured, ≥1 of the following muscles can become paralyzed:
  • Deltoid
  • Supraspinatus
  • Infraspinatus
  • Serratus anterior
  • Rhomboids
  • Clavicular head of pectoralis major
  • Teres minor
  • Biceps
  • Brachialis
  • Extensor carpi radialis longus and brevis
  • Flexors of wrist
  • Flexors of fingers
  • Intrinsic muscles of hand
• Fetal
• Labor related

Related Anatomy

• Neuropraxia: mildest injury involving damage only to the peripheral nerve and myelin sheaths; resolves spontaneously within a couple of months
• Axonotmesis: damage to axons and myelin sheath with peripheral nerve sheath intact; recovers spontaneously
• Neurotmesis: complete peripheral nerve rupture with complete or partial transection; requires nerve repair or reconstruction
• Pre-ganglionic avulsion: most severe injury of spinal cord roots; cannot be repaired by surgery and has the worst prognosis

Exam Findings, Signs and Positive Tests

Physical exam findings:

• Erb’s Palsy
  • The affected arm is adducted and internally rotated with extended elbow pronated forearm and extended wrist
  • Absence of Moro reflex
  • Absence of response on stimulation of the deltoid
  • Absence of active flexion at the elbow
  • Presence of grasping reflex and finger function
  • The hand may appear flaccid in the first few hours after birth
• Intermediate palsy or extended Erb’s palsy
  • The affected arm is adducted and internally rotated with elbow in extension, forearm in pronation, wrist in flexion and ulnar inclination
  • Absence of Moro reflex
  • Absence of response on stimulation of the deltoid
  • Absence of active flexion at the elbow
  • Presence of grasping reflex and finger function
  • The hand may appear flaccid in the first few hours after birth
• Klempke’s Palsy
  • The wrist and the hand are paralyzed; the elbow and shoulder retain normal function
  • The affected shoulder is abducted, arm in supination with bent elbow and extended wrist
  • "Claw hand" presentation
  • Signs of Horner’s syndrome may be present in case of avulsion injury of the nerve roots
• Total BPBP
  • Affected arm is inert and hanging loosely
  • Absence of deep tendon reflexes
  • Absence of sensory functions
  • Signs of Horner’s syndrome may be present in case of avulsion injury of the nerve roots

Work-Up Options

• Initial phase after birth
  • Clinical exam
    • Evaluate respiratory status to assess the status of phrenic nerve
    • Assess response to provocative stimulation
      • Moro reflex
      • Grasping reflex of the fingers
      • Stretch (myotatic) reflex
      • Cutaneous zone opposite to the muscle concerned
  • Assess motor recovery score
  • Assess sensory nerve function
  • Assess sensory functions corresponding to dermatomes closely
  • X-rays
    • Scapular girdle and the humerus to search for clavicular or humerus fracture
    • Chest if phrenic nerve involvement is suspected
• If spontaneous recovery is not seen in 3 months
  • Magnetic resonance imaging (MRI) to visualize spinal cord and certain areas of brachial plexus
    • Information from MRI is useful in deciding the nerve repair strategy
    • MRI of the shoulder in toddlers and older children to assess glenohumeral dysplasia and to identify candidates for shoulder tendon transfer

Incidence and Related Conditions

• Incidence of BPBP is estimated to be 0.4–2/1000 live births
• BPBP is most often unilateral; it rarely affects both arms
• Erb’s palsy is the most prevalent form, occurring in 46% of cases
• Extended Erb’s palsy/intermediate palsy occurs in 27% of cases
• Total BPBP occurs in 20% of cases
• Klemke’s palsy occurs in <2% of BPBP cases
• Glenohumeral dysplasia, or posterior shoulder dislocation, may occur in association with BPBP as early as 3 months of age in ~60–80% of BPBP cases
• Horner’s syndrome (characterized by constricted pupil, droopy eyelid and decreased sweating) may be present in cases of nerve root avulsion

Differential Diagnosis

• Pseudoparesis
• Amyoplasia congenita
• Congenita varicella syndrome
• Neurological lesions at other neuroanatomical levels
• Radial nerve palsy
• Physeal injury of the proximal humerus
• Septic osteoarthritis of the shoulder

A typical patient is an infant, with birth weight above 4 Kg, delivered using a vacuum or forceps after a prolonged labor associated with shoulder dyscotia. In some cases, clavicular fracture may have occurred. Movements of the affected upper limb are impaired, whereas the other limb shows active movement. Most often, muscles around the shoulder and the elbow are paralyzed, with fingers and wrist showing active movements. In some cases, all movements and sensory functions are absent in the affected upper limb. 

• Pseudoglenoid
• Internal rotation contractures
• Elbow rotation contractures

• Most patients with Erb’s palsy recover spontaneously by 3 months of age
• About 35% of BPBP cases sustain permanent neurological damage

• The type and extent of injury and speed of recovery should guide the next steps in management and/or surgical intervention.  

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2. Buterbaugh KL, Shah AS. The natural history and management of brachial plexus birth palsy. Curr Rev Musculoskelet Med 2016;9(4):418–26. PMID: 27680748
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5. Abzug JM, Kozin SH. Evaluation and management of brachial plexus birth palsy. Orthop Clin North Am 2014;45(2):225–32. PMID: 24684916
6. Executive summary: Neonatal brachial plexus palsy. Report of the American College of Obstetricians and Gynecologists’ Task Force on Neonatal Brachial Plexus Palsy. Obstet Gynecol 2014;123(4):902–4. PMID: 24785634
7. Coroneos CJ, Voineskos SH, Christakis MK, et al. Obstetrical brachial plexus injury (OBPI): Canada’s national clinical practice guideline. BMJ Open 2017;7(1):e014141. PMID: 28132014
8. Foad SL, Mehlman CT, Foad MB, Lippert WC. Prognosis following neonatal brachial plexus palsy: an evidence-based review. J Child Orthop 2009;3(6):459–63. PMID: 19885693
9. Sunderland S. A classification of peripheral nerve injuries producing loss of function. Brain  1951;74(4):491–516. PMID: 14895767
10. Nath RK, Kumar N, Avila MB, et al. Risk factors at birth for permanent obstetric brachial plexus injury and associated osseous deformities. ISRN Pediatr 2012;2012:307039 PMID: 22518326
11. Alfonso DT. Causes of neonatal brachial plexus palsy. Bull NYU Hosp Jt Dis 2011;69(1):11–6. PMID: 21332434
12. Evans-Jones G, Kay SP, Weindling AM, et al. Congenital brachial palsy: incidence, causes, and outcome in the United Kingdom and Republic of Ireland. Arch Dis Child Fetal Neonatal Ed 2003;88(3):F185-9. PMID: 12719390

New Articles

1. Abzug JM, Kozin SH, Waters PM. Open glenohumeral joint reduction and latissimus dorsi and teres major tendon transfers for infants and children following brachial plexus birth palsy. Tech Hand Up Extrem Surg 2017;Epub. PMID: 28448306
2. Wilson TJ, Chang KWC, Yang LJS. Prediction algorithm for surgical intervention in neonatal brachial plexus palsy. Neurosurgery 2017;Epub. PMID: 28419287
3. Abid A. Brachial plexus birth palsy: Management during the first year of life. Orthop Traumatol Surg Res 2016;102(1 Suppl):S125-132. PMID: 26774906
4. Buterbaugh KL, Shah AS. The natural history and management of brachial plexus birth palsy. Curr Rev Musculoskelet Med 2016;9(4):418–26. PMID: 27680748

Classics

1. Wolman B. Erb’s palsy. Arch Dis Child 1948;23(144):129–31. PMC1988073
2. Sunderland S. A classification of peripheral nerve injuries producing loss of function. Brain 1951;74(4):491–516. PMID: 14895767