The evaluation and management of neonatal brachial plexus palsy

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Neonatal brachial plexus palsy (NBPP), defined as weakness or flaccid paralysis of the upper extremity diagnosed soon after birth, results from injury of one or more cervical and thoracic nerve roots (C5–T1) ^[1]. The global incidence of NBPP ranges between 0.38 to 5.1/1000 live births, with regional variations depending on study setting (e.g., single centre, select populations), population-based data, and the availability of maternal-fetal care ^[2]-[5]. The incidence of NBPP in Canada, based on Canadian Institute for Health Information (CIHI) data, has been estimated at 1.24/1000 live births, with rates remaining stable from 2004 to 2012 ^[6]. NBPP is often a debilitating condition with long-term effects. Apart from physical and functional impairments, NBPP can impact family dynamics, a child’s global development, and quality of life ^[7]-[10].

This position statement updates a previous Canadian Paediatric Society (CPS) document published in 2006 ^[11] and offers revised recommendations for health care professionals (HCPs). It focuses on risk factors, clinical assessment and monitoring in the neonatal period, and the timing of referral to a multidisciplinary health care team to optimize outcomes.

Methods

Risk factors for NBPP

Historically, NBPP was believed to result from excessive downward traction after delivery of the fetal head in births with shoulder dystocia. While shoulder dystocia remains the strongest modifiable risk factor, it is increasingly recognized that NBPP can occur in its absence. Two postulated mechanisms are: 1) Injury sustained in utero and during descent (e.g., with uterine anomalies such as bicornuate uterus); and 2) Injury sustained at the time of expulsion ^[1][12]-[14]. Using CIHI data, one recent study ^[6] described a strong association with humeral fracture (odds ratio (OR) 115.02), shoulder dystocia (OR 59.85), and clavicular fracture (OR 30.96). Moderate association was noted with pre-existing maternal diabetes, forceps or vacuum-assisted delivery, episiotomy, fetal or birth asphyxia, macrosomia (>4.5 kg), and large for gestational age infants. Caesarean section (OR 0.15) and twin or multiple births (OR 0.45) were associated with decreased (but not zero) rates of NBPP. Canadian data agree with other published risk factors ^[2].

Shoulder dystocia is considered a modifiable risk factor and the implementation of a standardized, evidence-based practice bundle (including risk assessment at admission, a “time-out” before operative delivery, and low-fidelity shoulder dystocia drills) has been demonstrated to reduce the rate of shoulder dystocia and NBPP in select populations ^[15]. 

Classification, type of injury, and clinical presentation

NBPP is characterized by the type and patterns of nerve injury. Clinically, the Narakas classification system ^[16] is used to group severity of injury from I to IV (Table 1), with groups I and II associated with higher rates of spontaneous recovery. Types of nerve injury range from neuropraxia (a temporary conduction block due to interruption of the myelin sheath, with recovery of full function generally within weeks), to axonotmesis (disruption of the nerve fibers and, likely, the myelin sheath, with some function returning within months but incomplete recovery), to neurotmesis (nerve disruption and avulsion of the nerve roots from the spinal cord, with no chance of recovery). Clinical presentation can range from transient weakness to global paresis, with passive greater than active range of motion.

Infants with total plexus injury (groups III and IV) who show no signs of recovery will need reconstructive microsurgery to repair the injured plexus and improve outcome. Infants with neuropraxic injury who fully recover by 1 month of age are managed conservatively. However, a ‘gray zone’, where optimal therapy (i.e., the decision whether to intervene surgically) is unclear, certainly exists for infants with NBPP. This gray zone includes infants with a deficit that has been managed conservatively but who may be considered for surgery based on select criteria, such as no recovery of biceps function at 3 months of age, or a failed cookie test at 9 months.

One prospective study ^[17], reported that 81% of infants were in the gray zone, with only 44% experiencing complete recovery. This categorization was based on serial examination, incorporation of the Active Movement Scale (AMS) score to determine changes in movement over time and recovery status, and the development of an algorithm for management options based on AMS scores. Another more recent study ^[18] reported similar findings. Infants with severe NBPP were identified by 1 month of age based on elbow extension, elbow flexion, and motor unit potential in the biceps muscle on electromyography. Study authors concluded that infants with no active elbow extension at 1 month should be referred to a specialized centre.

With any nerve injury, the likelihood and extent of spontaneous recovery is weighed against the potential benefits of an operative intervention. Overall, the current evidence overwhelmingly supports nerve repair for infants with deficits as early as 3 months ^[19], with low rates of reported adverse events. Population data suggest that nerve repair is underutilized for this population, due in part to gaps or delays in referral for specialized assessment ^[20].

Regularly scheduled clinical examinations just after birth and throughout the neonatal period are essential to assess recovery, especially because nerve injuries of different severity present with the similar clinical features. One systematic review of prospective and retrospective studies on the natural history of NBPP has suggested that 20% to 30% of infants in demographic samples do not recover fully ^[21]. Recovery in infants with Erb’s palsy ranges from 69% to 95%, while almost 80% of children with global C5-T1 injuries have persistent deficits at 18 months ^[21]. The long-term consequences of persistent NBPP may include weakness, development of skeletal malformations (e.g., contractures, limb length discrepancy), and cosmetic deformities ^[3][22]

Pathways for managing NBPP

A clinical practice guideline on brachial plexus palsy published in 2017 by the Canadian Obstetrical Brachial Plexus Injury Working Group was the starting point for this revision ^[23]. Clinicians from ten multidisciplinary centres identified four main gaps in the continuum of care for these injuries: 1) historic lack of evidence use; 2) timing of referrals for multidisciplinary care; 3) indications and timing for operative nerve repair; and 4) distribution of expertise. To address these gaps and improve the evidence base, experts developed seven specific recommendations, three of which are related to newborn care. For providers of neonatal care in hospital and community settings, these recommendations follow here, with discussion.

1) Focused history and physical examination at the time of birth are required

HCPs experienced in newborn assessment should undertake a detailed review of maternal history and delivery details to identify risk factors for NBPP (e.g., shoulder dystocia or presence of humeral or clavicular fracture). They should perform a detailed physical musculoskeletal and neurological examination, including active and passive range of motion, and assess normal reflexes. This exam should include assessing for clavicular or humeral fracture, which can mimic NBPP due to pain limiting range of motion.

When concern is raised for bony injury, a chest and humeral x-ray should be obtained. Assess respiratory status and check symmetry of chest movements promptly to assess for phrenic nerve injury. An elevated hemi-diaphragm may be seen on chest x-ray or detected on ultrasound. The presence of Horner’s syndrome and diaphragmatic paralysis suggest an avulsion injury, which is a persistent, definitive deficit. Detailed documentation should be part of the newborn record and included in the referral form (Table 2). Differential diagnoses to be considered include: pseudoparesis (i.e., pain secondary to humeral fracture or to an infection of the bone, joints, soft tissue, or vertebra); myotonia congenita (a form of arthrogryposis multiplex congenita (AMC)); anterior horn cell injury (e.g., congenital cervical spinal atrophy, congenital varicella syndrome); and pyramidal tract or cerebellar lesions ^[24].

2) Appropriate timing and organizing information for referral to a multidisciplinary health care team are essential to outcome

If NBPP recovery is incomplete by 1 month of age (i.e., active elbow extension and flexion remain absent) as assessed by an HCP with expertise in musculoskeletal and neurological examination, it predicts severe NBPP ^[18] and the infant should be referred to a brachial plexus multidisciplinary health care team. Incomplete recovery of any upper extremity movement at 1 month suggests nerve injury beyond neuropraxia, and assessment by a specialist team is needed. One major barrier to referral is that primary care providers often overestimate recovery ^[18].

The multidisciplinary health care team should include a physiotherapist or occupational therapist or equivalent and a paediatric surgeon (plastic surgeon, orthopedic surgeon, or equivalent). A timely referral optimizes early management, including operative evaluation and appropriate regular follow-ups, with anticipatory guidance and education for parents. Parents have reported a preference for early referral to a multidisciplinary health care team because they are more likely to receive information on therapeutic options, and counselling in case of persistent deficits or regarding prognosis ^[25].

The following information should always be part of a child’s file at the time of referral (Table 2): maternal and neonatal risk factors (mode of delivery, instrumented delivery, birth weight, shoulder dystocia, associated clavicular or humeral fracture), severity of injury (side of deficit, presence of Horner’s syndrome, presence of active movement at the shoulder, elbow, wrist, or finger level, as well as paralysis in these locations), and course of recovery. Referral should not be delayed while obtaining such clinical records, however.

3) Non-operative therapy delivered outside of a multidisciplinary centre is key to quality care

No studies to date have assessed the impact of non-operative therapy delivered in the community compared with care delivered by a specialized multidisciplinary health care team. However, expertise in brachial plexus evaluation is key to recognizing and characterizing residual neuromuscular deficits (subtle functional impairment which would need surgery), a skill which community providers may not have. As a child grows and matures, family-centred communication would identify issues of growth and development (e.g., pain syndromes, functional deficits). Optimally, NBPP management should be a continuous dialogue among a child’s multidisciplinary brachial plexus team, community health care providers, and non-operative therapists). 

Recommendations

1. Neonatal care providers should evaluate newborns for NBPP when delivery has been complicated by shoulder dystocia, a humeral or clavicular fracture, or when asymmetrical upper extremity movement is apparent.
2. All newborns with NBPP and incomplete recovery by 1 month of age should be referred immediately to a multidisciplinary health care team to optimize outcomes and minimize residual deficits. The referral should include detailed information on the risk factors, severity of injury, and course of recovery.
3. For infants receiving ongoing non-operative therapy in their community, continuous dialogue among the child’s multidisciplinary health care team, community health care providers, and non-operative therapists is required to identify issues of growth and development and facilitate specialized assessments.

Acknowledgements

Special thanks are due to Elizabeth Uleryk, Information Specialist, who conducted the literature search for this revision. This statement was reviewed by the Community Paediatrics Committee of the Canadian Paediatric Society, and by the Canadian Association of Occupational Therapists and the Canadian Physiotherapy Association.

CANADIAN PAEDIATRIC SOCIETY FETUS AND NEWBORN COMMITTEE

Members: Gabriel Altit MD, Nicole Anderson MD (Resident Member), Heidi Budden MD (Board Representative), Leonora Hendson MD (past member), Souvik Mitra MD, Michael R. Narvey MD (Chair), Eugene Ng MD, FRCPC, Nicole Radziminski MD, Vibhuti Shah MD, FRCPC, MSc (past member)

Liaisons: Radha Chari MD (The Society of Obstetricians and Gynaecologists of Canada), James Cummings MD (Committee on Fetus and Newborn, American Academy of Pediatrics), William Ehman MD (College of Family Physicians of Canada), Danica Hamilton RN (Canadian Association of Neonatal Nurses), Chloë Joynt MD (CPS Neonatal-Perinatal Medicine Section Executive), Chantal Nelson PhD (Public Health Agency of Canada)

Principal authors: Vibhuti Shah MD, FRCPC, MSc, Christopher J Coroneos MD, MSc, FRCSC; Eugene Ng MD, FRCPC

References

Disclaimer: The recommendations in this position statement do not indicate an exclusive course of treatment or procedure to be followed. Variations, taking into account individual circumstances, may be appropriate. Internet addresses are current at time of publication.