Basics
Description
- The brachial plexus contains sensory and motor nerves to the upper extremities, stemming from the cervical and thoracic spine (commonly C5 " �T1 roots).
- The brachial plexus contains a consistent pattern of nerves that innervate predictable muscles and skin regions.
- Brachial birth palsy is a proximal stretch, avulsion, or rupture type injury and may involve
- C5 " �C6 (Erb palsy), most common, best prognosis
- C5 " �C7, less common, worse prognosis
- C5 " �T1, least common, flail extremity and worst prognosis
Epidemiology
- There is no predominance of gender, but variations in clinical care, preventive measures, and birth weight may explain estimates of incidence to range from 0.4 to 4 per 1,000 live births.
- Incidence drops from 0.2% with vaginal delivery to 0.02% after cesarean section as there is a probable mechanical basis for the plexopathy.
- Erb palsy is the most commonly encountered plexus injury.
Risk Factors
- Large size for gestational age, multiparity, prolonged labor, breech position, difficult delivery " �especially when forceps- or vacuum-assisted
- Diabetic mothers and/or neonatal birth weight >4.5 kg
- Although there is no genetic basis per se, previous delivery leading to obstetric palsy is a risk factor.
General Prevention
- Careful positioning of the upper extremity during childbirth and conversion to cesarean section when necessary
- Prevention of long-term disability and contracture can be minimized with exercise of the child 's joints and functioning muscles every day beginning at 3 weeks of age.
Pathophysiology
- Seddon and Sunderland have described classification systems to describe degree of injury.
- Neuropraxia
- Mildest form, interruption of conduction, axons continuous
- Good recovery
- Axonotmesis
- Axonal degeneration with loss of axonal continuity
- Nerve intact. Epineurium and perineurium intact.
- Neurotmesis
- Most severe, nerve is completely contused. Axonal discontinuity
- Nerve may be grossly intact, but epineurium, perineurium, and axons disrupted. Recovery difficult to predict.
Etiology
- Downward mechanical force on the shoulder during difficult delivery can lead to stepwise stretch injury leading to transient or permanent damage or total avulsion of nerve roots.
- Upward mechanical force, that is, after face delivery, leads to C8 " �T1 injury (Klumpke).
- Avulsion injury carries the worst prognosis, particularly if proximal to the cell body of the motor nerve (preganglionic), as these injuries cannot spontaneously recover.
Associated Injuries
Horner syndrome, phrenic nerve injury, and long thoracic nerve injury (winged scapula) may be observed and are associated with preganglionic injury and a poor prognosis. � �
Diagnosis
History
- In neonates: obstetric history including birth weight, use of assistive devices, multiparity, perinatal difficulties, previous difficult deliveries, etc.
- Despite a prominent association between shoulder dystocia and neonatal brachial plexus palsy injury, some of these injuries occur without any shoulder dystocia.
- In older children: Consider recent infectious processes (viruses), tetanus shots, trauma, and tumor.
Physical Exam
- Serial examination is key for predicting recovery.
- Active and passive ROM testing, bulk, deep tendon reflexes (DTRs), autonomic function, and evaluation for phrenic nerve injury and paravertebral muscle weakness are important adjunctive exams.
- Sensory testing may be more challenging because of age and overlap of dermatomes.
- Because of invariability of brachial plexus anatomy, injury patterns yield predictable disabilities.
- Erb palsy
- Associated with downward force on the head and neck during delivery, leading to upper plexus injuries
- Shoulder limp, adducted, internally rotated
- Elbow extended, forearm pronated, wrist and fingers flexed ( "waiter 's tip " � posture)
- Hand grip and intrinsic function generally preserved. Shoulder and elbow flexion is weak.
- DTRs: biceps and brachioradialis absent, Moro asymmetric
- Klumpke palsy
- Risk of injury to the lower brachial plexus results from traction on an abducted arm, as with an infant being pulled from the birth canal by an extended arm above the head.
- Shoulder intact, elbow flexed, forearm supinated, wrists and fingers extended
- Hand grip is weak, while shoulder and elbow function may be normal. Horner syndrome can be present.
- DTRs: triceps absent; Horner sign suggests ipsilateral T1 injury.
- Complete plexus injury ( "flail " �):
- Entire extremity and shoulder girdle is flaccid, anesthetic, and areflexic.
Diagnostic Tests & Interpretation
- Plain radiographs may demonstrate clavicle injury and shoulder and elbow subluxation and dislocation.
- MRI neurography is generally favored over CT myelography and electromyography (EMG) and is less invasive.
- Previous cases using EMG data to determine whether an injury occurred in utero has been investigated; interpretation of all these modalities may lead to false positives and negatives.
- Somatosensory and motor evoked potentials are less useful as they generally corroborate physical exam findings.
Follow-Up
- Following the diagnosis of brachial plexus palsy, neonates should be followed closely to determine if the injury will resolve spontaneously or will require further treatment.
- Patients should be followed by an experienced multidisciplinary brachial plexus team of therapists, pediatricians, and pediatric surgery subspecialists.
Differential Diagnosis
- Important to rule out clavicular, shoulder, elbow, and humeral injury as primary cause of limb paresis or weakness
- Central lesions resulting from tumors and strokes, as well as spinal cord lesions, should be considered.
- Congenital contractures and limb deformities can resemble brachial plexus injuries.
- Central paralysis is generally spastic and peripheral (i.e., brachial plexus or lower motor neuron) is flaccid.
- Horner syndrome may be associated with proximal injury.
- Parsonage-Turner syndrome may cause plexus inflammation and symptoms without obvious injury.
Treatment
Rehabilitation
- Therapy is paramount in managing symptoms of plexopathy.
- Goals include comfort, optimizing recovery, and assessing improvement.
- Stretching exercises, splints to prevent contracture, joint taping to stabilize shoulder, and sensory awareness activities are commonly used.
General Measures
- Palsies must be observed during the first weeks to months of life.
- Immobilization of a flaccid limb encouraged very early for pain control
- After 3 weeks of immobilization and fractures/dislocation have been ruled-out, ROM exercises should commence to prevent deformity and contracture.
- Majority of neonates with obstetric brachial plexus injury will resolve spontaneously.
- Classic Erb palsy has the best prognosis.
- The majority of upper brachial plexus birth injuries are transient.
- Global palsies have a poor prognosis with nonoperative treatment.
- Failure to recover antigravity biceps function by 3 " �6 months of age is a poor prognostic sign.
- Infants with C5 " �6 or C5 " �7 injuries may continue to demonstrate spontaneous improvement up to 9 months of age, thus precluding the need for early surgery.
Prognosis
� � �75 " �85% of all patients regain very good to full strength and function, with 1/2 doing so rapidly (the mild group) and 1/2 more slowly (the moderate group). � �
Surgery/Other Procedures
- Indications for early surgical intervention
- Pan-plexus ( "flail " �) lesions (generally warrant early intervention as soon as 3 months if no improvement)
- All brachial plexus injuries should be evaluated by a multidisciplinary team at 3, 6, and 9 months of age. Failure to improve at each examination is usually and indication for surgery. There are several different grading systems, which can be used to assess an infant 's healing progress.
- Nonsurgical measures
- Neuromuscular electrical stimulation can be used as part of an infant 's comprehensive therapy to help improve blood flow, preserve muscle bulk and minimize atrophy.
- Botulinum toxin A therapy to impair preserved muscle groups allow weaker muscle groups to strengthen.
- Primary surgery
- Surgical outcome is best if performed by 6 " �12 months and probably not useful if done after 24 months; ongoing care
- Exploration generally confirms clinical and radiographic findings.
- Injured nerves generally present as neuromas.
- Neurolysis to free uninjured nerve from scar versus
- Excision of neuroma en bloc with interpositional nerve grafting
- Excision is favored when nerve transmission across the injured site is significantly diminished (<50%) or absent, immobilization of a flaccid limb encouraged very early for pain control
- Autologous sural nerve is an excellent donor, and it is reversed when interposed to maximize signaling to the CNS
- When there is insufficient nerve graft, neurotization " �attachment of functional motor nerves to distal recipient nerves " �is a useful adjunct.
- Common donor nerves include the spinal accessory, contralateral C7 nerve root, and intercostal nerves.
- Use of nerve conduits and adjunctive neurotrophic factors is under investigation.
Ongoing Care
Secondary Surgery
Tendon transfers (generally wait 2 " �4 years to assess long-term nerve recovery) improve flexibility and functional mobility of affected joints. � �
- Shoulder: transfer of preserved internal rotators to impaired abductors and external rotators
- Elbow: triceps to biceps repair, pectoralis to biceps repair, latissimus to biceps repair
- Forearm: Biceps rerouting and pronator lengthening can relieve pronation and supination contractures.
- Scapula: contralateral rhomboid, trapezius, and latissimus transfer to anchor and support a winged scapula
- Osteotomies (late presentation)
- External rotational osteotomy of humerus to improve upper extremity function with fixed, internally rotated shoulder
- Radius rotational osteotomy to address pronation and supination deformities
- Soft tissue (late presentation)
- Capsulotomies and joint manipulation under anesthesia can facilitate movement in a contracted joint.
- Local flaps and tissue transfer can augment a contracted flexor or extensor zone.
Additional Reading
- Borschel � �GH, Clark � �HM. Obstetrical brachial plexus palsy. Plast Reconstr Surg. 2009;124(1)(Suppl):144e " �155e. � �[View Abstract]
- Chuang � �DC, Ma � �HS, Wei � �FC. A new evaluation system to predict the sequelae of late obstetric brachial plexus palsy. Plast Reconstr Surg. 1998;101(3):673 " �685. � �[View Abstract]
- Chuang � �DC, Ma � �HS, Wei � �FC. A new strategy of muscle transposition for treatment of shoulder deformity caused by obstetric brachial plexus palsy. Plast Reconstr Surg. 2008;101(3):686 " �694. � �[View Abstract]
- Seddon � �HJ. Three types of nerve injury. Brain. 1943;66:237 " �288.
- Terzis � �JK, Papakonstantinou � �KC. Management of obstetric brachial plexus palsy. Hand Clin. 1999;15(4):717 " �736. � �[View Abstract]
- Wolfe � �SW, Strauss � �HL, Garg � �R, et al. Use of bioabsorbable nerve conduits as an adjunct to brachial plexus neurorrhaphy. J Hand Surg Am. 2012;37(10):1980 " �1985. � �[View Abstract]
- Zafeiriou � �DI, Psychogiou � �K. Obstetrical brachial plexus palsy. Pediatr Neurol. 2008;38(4):235 " �242. � �[View Abstract]
Codes
ICD09
- 767.6 Injury to brachial plexus due to birth trauma
ICD10
- P14.3 Other brachial plexus birth injuries
SNOMED
- 206226005 brachial plexus palsy due to birth trauma (disorder)
- 81774005 Klumpke-Dejerine paralysis as birth trauma (disorder)
FAQ
- Q: My baby was diagnosed with a brachial plexus injury. What are the odds she will recover completely?
- A: Most (roughly 80%) children recover completely. The nerves were stretched and are inflamed, but this should resolve. Babies with more significant injuries causing axonotmesis and neurotmesis may not recover completely or at all.
- Q: My last baby suffered a brachial plexus injury at birth, but since got better. What are the odds my next child will have the same problem?
- A: Your next child has a 14-fold increase in risk for brachial plexus injury compared to the general population.
- Q: My baby is 3 months old and cannot move his left arm? Whom should I call?
- A: A center for brachial plexus injury is ideal. A well-organized team includes physical and occupational therapists, neurologists, and surgeons (neurosurgeon, plastic surgeon, orthopedic surgeon, or combination thereof).
- Q: Could my obstetrician have prevented this?
- A: Likely, not. Although there may be increased risk for shoulder dystocia in some women, it is not a diagnosable problem. Preemptive cesarean section in at-risk women may be unnecessarily risky to mother and fetus.