, Ratna Maheshwari2 and Shalin Maheshwari2
(2)
Pediatric Orthopedics, Childrens’ Orthopedic Centre, Mumbai, India
Take-Home Message
Failure of antigravity biceps recovery by 3–6 months is an indication for microsurgery in BPBP
Definition
Brachial plexus birth palsy (BPBP) is a traction or compression injury sustained to the brachial plexus during birth.
Incidence reported to be 0.1–0.4 % of live births.
Etiology
Risk factors include macrosomia, shoulder dystocia/difficult delivery, prior BPBP. Vacuum- or forceps-assisted deliveries are also at risk.
Vertex presentation accounts for most of the cases (94–97 %), breech presentations account for 1–2 % of cases, and caesarean deliveries account for 1 % of cases.
Pathophysiology
The mechanism of injury is forceful separation of the head from the shoulder by lateral flexion of the cervical spine and depression of the shoulder.
Classification
Anatomic: Upper trunk, lower trunk, total plexus.
Neurologic: Neurapraxia is paralysis in the absence of peripheral degeneration; the delay to recovery may be long, but recovery will be complete. Axonotmesis is damage to nerve fiber with complete peripheral degeneration but with intact external tissues to provide support for accurate spontaneous regeneration. Good recovery is anticipated, and no intervention can improve the outcome. In neurotmesis all essential structures, both neural and supporting tissues, have been disrupted. This category includes neuroma in continuity, division of nerve, and anatomic disruption.
Narakas Classification
Group I: The classic Erb (C5–C6) palsy with initial absence of shoulder abduction and external rotation, elbow flexion, and forearm supination. Wrist and digital flexion and extension are intact. Successful spontaneous recovery as high as 90 %.
Group II: Includes involvement of C7 along with C5 and C6 impairment.
Group III: Flail extremity but without a Horner’s syndrome.
Group IV: The most severe involvement is a flail extremity and Horner’s syndrome. Preganglionic lesions are avulsions from the cord that will not spontaneously recover motor function. Preganglionic lesion is suggested by the presence of a Horner’s syndrome, elevated hemidiaphragm, winged scapula, and the absence of rhomboid, rotator cuff, and latissimus dorsi function.
Functional status – Toronto test score (see Table 1).
Table 1
Toronto test score
Elbow flexion
0–2
Elbow extension
0–2
Wrist extension
0–2
Digital extension
0–2
Thumb extension
0–2
Total score
0–10
Modified Mallet Classification is used to assess residual deformity at shoulder. It is scored on the following parameters: global abduction; global external rotation; ability to take hand to neck, hand to spine, and hand to mouth; and internal rotation.
Evaluation
EMG and NCV may help differentiate neuropraxia from axonal degeneration.
CT myelography and MRI can identify preganglionic nerve root injuries if they are associated with traumatic pseudomeningoceles.
X-ray changes may be seen in late presentation like retroversion of the glenoid, posterior subluxation, and medial flattening of the humeral head.
Management
Initial phase involves giving rest to the extremity up to 3 weeks followed by gradual mobilization at the end of 3 weeks.
If antigravity biceps function recovers by 2 months, full recovery is anticipated. If biceps function recovers at or after 5 months, incomplete recovery is likely. The presence of Horner’s syndrome is associated with worse prognosis.
Indications for surgery: When no clinical recovery of deltoid and biceps at 3 months supported by EMG and total palsy at birth with Horner’s syndrome. Current recommendations for the timing of microsurgical repair range between the ages of 3 and 9 months.
If biceps function is absent at 3 months, one may consider microsurgery or observe for a further 3 months.Related posts:
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