Dr. Kevin Yip

Dr Kevin Yip
Orthopaedic Surgeon
MBBS(UK), FRCS(EDIN), FAM(SING), FHKCOS(ORTHO)

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Brachial Plexus Birth Palsy

Basics
Description
  • Brachial plexus palsy results from stretch during birth that is caused by downward or upward traction on the arm.
  • Secondarily, the muscles and bones of the upper extremity become contracted or deformed over time because of the resultant muscle imbalance.
  • Although the injury occurs at birth, in mild cases it may not be detected until the baby tries to use the extremity.
  • Classification:
    • Type I (Erb palsy): Injury to roots 4-6 of the cervical spine
    • Type II (whole-brachial plexus palsy): C4-T1 involved; also known as Erb-Duchenne-Klumpke palsy
    • Type III (Klumpke palsy): C8-T1 involved
  • Synonyms: Birth palsy; Obstetric palsy; Erb palsy; Klumpke palsy
General Prevention
  • Sometimes obstetricians will advise a caesarean section if a baby seems extremely large or cephalopelvic disproportion is present.
  • Not all cases can be anticipated or prevented.
Epidemiology
Incidence
  • Currently, the incidence is 0.8 per 1,000 live births.
    • This figure is a decline from the rate in 1900, when it was reported twice as often.
    • The change most likely results from improved obstetric care.
  • Erb palsy is ~4 times as common as Klumpke palsy.
  • No recognized difference exists in incidence between boys and girls.
Risk Factors
  • Fetal malposition
  • Shoulder dystocia
  • Cephalopelvic disproportion
  • High birth weight:
    • Maternal diabetes
  • Use of forceps in delivery
Pathophysiology
  • Pathologic findings vary from stretch to disruption of the nerves of the brachial plexus.
  • The injury may occur at the cervical foramen as the nerves exit the spinal canal (poorer prognosis), or farther down in the neck and shoulder.
  • Secondary muscle atrophy and contracture ensues.
Etiology
  • Erb palsy results from downward traction on the shoulder or arm or lateral traction against the neck.
  • Klumpke palsy is secondary to upward traction on the arm.
  • Both occur because of the force needed in a difficult extraction.
Associated Conditions
  • High birth weight
  • Gestational diabetes
Diagnosis
Signs and Symptoms
  • Decreased active use of the extremity
  • Arm held in internal rotation
  • Loss of full active or passive external rotation
  • Inability to abduct (raise) the shoulder
  • Atrophy of the involved muscles (late)
  • Elbow flexion contracture
  • Possible Horner syndrome in Klumpke palsy
  • The condition is not painful.
  • A loss of sensation may be noted with complete plexus injuries.
History
  • Decreased infant arm movements sometimes are noted from birth.
  • In other cases, more subtle decreases in shoulder movement or presence of arm contracture may not be noted until later.
Physical Exam
  • Physical examination is the primary means of diagnosis.
    • Palpate for tenderness over the clavicle, proximal humerus, and ribs.
    • Test sensation by responses to light touch or pinch.
    • Test the function of all muscles in the shoulder, elbow, and hand by stimulation and observation.
  • In patients with Erb palsy, the shoulder is internally rotated and lacks external rotation and abduction.
  • In Klumpke palsy, loss of finger and interosseous function occurs.
Tests
Imaging
  • Plain radiographs often are indicated at birth to rule out other injuries that may cause decreased movement of the infant’s arm (clavicle fracture, proximal humerus fracture); such injuries may coexist with brachial plexus birth palsy.
  • At the time of late reconstruction in a child >4 years old who has residual shoulder imbalance, plain radiographs and CT scans are indicated to assess the shape of the glenohumeral joint.
Diagnostic Procedures/Surgery
  • An electromyogram should be obtained if no clinical return of deltoid or biceps function occurs by 3-6 months of age.
    • Lack of reinnervation may be a relative indication for surgery.
  • Cervical myelography may be helpful for diagnosing the level of injury.
    • Meningoceles seen at the root levels in the cervical spinal cord indicate that roots were avulsed from the cord, and the prognosis is poor.
    • A finding of meningoceles indicates that different strategies may be needed at surgery.
Differential Diagnosis
  • Clavicle fracture:
    • Usually painful to palpation
    • Some shoulder motion may be elicited.
  • Proximal humeral physeal fracture:
    • Same findings as clavicle fracture, with tenderness over the proximal humerus; the abnormality may not show on radiographs because the proximal humerus is not ossified at birth.
    • Ultrasound or MRI studies may be diagnostic, as are plain films 7-10 days later.
  • Septic arthritis of the shoulder:
    • May cause pseudoparalysis
    • Fever in the newborn may not be pronounced.
Treatment
General Measures
  • Parents should stretch the infant’s arm several times a day as directed by the occupational therapist.
  • The patient should be referred to a specialized pediatric orthopaedic surgeon for monitoring and decision-making.
  • Observation and passive ROM are indicated for the newborn; ~80% of patients recover spontaneously by 1 year of age.
  • Splinting is not necessary, but continued follow-up is needed.
  • Surgery is indicated for the remaining 20% of patients, with grafting of the injured nerves (if no meningoceles are present and the elapsed time is not >1-2 years) or with tendon transfers to improve muscle balance-.
Activity
  • No restrictions
  • Encourage passive ROM.
Special Therapy
Physical Therapy
  • An occupational therapist is helpful in teaching the parents how to stretch and what contractures to watch for.
  • Splinting is not needed, but stretching and passive ROM are encouraged.
Surgery
  • Nerve repair/reconstruction:
    • May be performed with an operative microscope with direct repair or grafting of the injured nerves if the patient’s function does not return in ~6 months.
    • The exact timing is controversial.
  • Tendon transfers may be performed later to restore external rotation to the shoulder.
  • Release of the tight internal rotators also may be indicated.
  • Humeral osteotomy is another way to restore an externally rotated position.
  • Several muscle transfers are available to restore elbow flexion, most notably the latissimus transfer.
  • Transfers for finger and wrist function are least commonly needed.
Follow-up
Disposition
 
Issues for Referral
It is important to refer the baby with brachial birth palsy to an orthopaedic surgeon with an interest in this condition because it is a specialized field.
 
Prognosis
  • 80% of patients with brachial plexus birth palsy recover spontaneously.
  • Surgery may help many of the remainder.
Complications
  • Contracture of shoulder, elbow, or wrist
  • Affected extremity smaller in length and girth
  • Sensory loss
  • Shoulder dislocation
Patient Monitoring
The patient should be seen approximately every 2-3 months to look for return of function and to plan for appropriate diagnostic testing.
 
 
Miscellaneous
Codes
ICD9-CM
767.6 Brachial plexus birth palsy
 
Patient Teaching
  • The prognosis should be outlined to the parents, so they can plan ahead.
  • The possibility of contractures should be explained, so the parents will be motivated to continue the stretching exercises.
Activity
No activity restrictions
 
Prevention
  • Management of gestational diabetes
  • Caesarean delivery if cephalopelvic disproportion is clinically significant.
FAQ
Q: Why is immediate surgical repair of the brachial plexus not indicated at birth?
A: Because most lesions are stretch lesions (neurapraxias) that will improve spontaneously. Surgery on these nerves may disrupt intact channels.
 
Q: What is the latest age at which nerve repair may be performed?
A: It should not be performed much after the age of 12-18 months because reinnervation may not succeed.

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