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Obstetric Brachial Plexus Injury (OBPI)

Overview

Obstetric brachial plexus injury (OBPI) is a type of peripheral nerve injury that occurs when the network of nerves that supplies the arm (the brachial plexus) is stretched or torn during childbirth. The brachial plexus is formed by the C5‑C8 and T1 spinal nerve roots and controls movement and sensation in the shoulder, arm, and hand. When these nerves are damaged, the newborn can experience weakness, loss of motion, or even permanent paralysis of part or all of the affected limb.

Who it affects: OBPI is a newborn condition, so it only occurs in infants delivered vaginally or by cesarean section. While it can affect any newborn, certain maternal and delivery factors increase the risk.

Prevalence: The incidence varies worldwide, ranging from 0.4 to 5.0 per 1,000 live births (≈0.04‑0.5 %). In the United States, recent estimates suggest about 1.5 cases per 1,000 live births (~150,000 infants per year) <sup>[1][2]</sup>. The majority are mild (Erb’s palsy) and improve spontaneously, but up to 10‑15 % develop permanent functional deficits requiring surgery <sup>[3]</sup>.

Symptoms

The clinical picture depends on which part of the brachial plexus is injured. Below is a comprehensive list, organized by the most common patterns.

1. Erb’s Palsy (Upper‑Trunk Injury – C5‑C6)

• Weakness of shoulder abduction and external rotation – arm hangs limp at the side.
• Elbow flexion weakness – difficulty bending the elbow.
• Forearm supination loss – hand turns inward (pronated).
• Typical posture: “Waiter’s tip” – arm adducted, internally rotated, elbow extended.

2. Klumpke’s Palsy (Lower‑Trunk Injury – C8‑T1)

• Weakness of hand and finger flexors, especially the intrinsic muscles.
• Loss of grip strength.
• Claw hand deformity (hyperextension of the metacarpophalangeal joints, flexion of the interphalangeal joints).
• Possible sensory loss on the ulnar side of the forearm and hand.

3. Total Brachial Plexus Palsy (C5‑T1)

• Flaccid paralysis of the entire arm and hand.
• Absence of all shoulder, elbow, wrist, and finger movements.
• Severe sensory loss over the entire upper limb.

4. Associated Symptoms

• Asymmetry of the chest wall (shoulder girdle droop).
• Reduced spontaneous movement of the affected limb during the first few weeks of life.
• Visible muscle atrophy after 4‑6 weeks if no improvement occurs.
• Rarely, associated fractures (clavicle or humerus) or brachial plexus avulsion (nerve roots torn from the spinal cord).

Causes and Risk Factors

OBPI results from excessive traction or stretching of the neck and shoulder during delivery. The exact mechanism is often a combination of forces.

Primary Causes

• Shoulder dystocia: The fetal head delivers, but the shoulders become impacted behind the maternal pubic symphysis.
• Excessive pulling on the umbilical cord while attempting to expedite delivery.
• Instrumental delivery (forceps or vacuum) that adds additional traction.
• Large fetal size (macrosomia) – birth weight >4,000 g (≈9 lb).
• Maternal diabetes – increases the risk of macrosomia and shoulder dystocia.
• Premature delivery – a fragile, less‑myelinated plexus may be more susceptible to traction.

Risk Factors

• Previous infant with OBPI (recurrence risk ~2‑5 %).
• Maternal obesity (BMI > 30 kg/m²).
• Prolonged second stage of labor (>2 hours for nulliparous, >3 hours for multiparous).
• Operative vaginal delivery (forceps or vacuum).
• Fetal malposition (breech, transverse lie).
• Assisted delivery in a breech presentation where the arm is trapped.

Diagnosis

Timely recognition is essential. Diagnosis combines clinical examination with imaging and electrophysiological studies.

Clinical Examination

• Assessment of spontaneous movements in the first 24‑48 hours.
• Berliner or Narakas classification systems to grade severity.
• Evaluation of motor function (shoulder, elbow, wrist, hand) and sensory testing.

Imaging Studies

• Ultrasound: High‑frequency (10‑15 MHz) probes can visualize nerve continuity and muscle bulk within the first weeks.
• MRI (Neurography): Provides detailed anatomy, especially for root avulsion; often performed after 3–4 months if recovery is uncertain.
• X‑ray: To rule out associated clavicular or humeral fractures.

Electrophysiological Tests

• Electromyography (EMG) & Nerve Conduction Studies (NCS): Usually performed after 3 weeks (when fibrillation potentials appear) to assess denervation, reinnervation, and prognosis.
• Results guide the decision for early surgical exploration (typically at 3‑6 months).

Diagnostic Timeline

1. Birth – visual assessment and documentation of any abnormal positioning.
2. Day 1‑3 – detailed neurologic exam.
3. Week 2‑4 – repeat exam; if no improvement, order ultrasound.
4. Month 2‑3 – EMG/NCS if recovery plateaued.
5. Month 3‑6 – MRI if avulsion suspected; discuss surgical options.

Treatment Options

Management is multidisciplinary, involving pediatric neurologists, orthopedic surgeons, physiotherapists, and occupational therapists.

Conservative (Non‑Surgical) Management

• Physical therapy (PT): Gentle passive range‑of‑motion (PROM) exercises 2‑3 times daily to prevent contractures.
• Occupational therapy (OT): Play‑based functional activities to stimulate motor pathways.
• Splinting/orthoses: Positioning devices (e.g., shoulder harness, elbow flexion splint) to maintain proper alignment.
• Serial casting: In cases of early contracture, casts are applied and changed weekly.
• Parent education: Home‑based stretching program, handling techniques to avoid overstretch.

Most infants with Erb’s palsy (≈70‑90 %) improve spontaneously by 3‑6 months with diligent therapy.

Surgical Interventions

Surgery is considered when there is little or no clinical improvement by 3‑6 months, or if EMG/NCS indicates severe denervation.

• Nerve grafting: Autologous sural nerve grafts bridge gaps in the plexus.
• Nerve transfers: Transfer of expendable donor nerves (e.g., spinal accessory nerve to suprascapular nerve) – now the preferred technique for upper‑trunk injuries.
• Muscle/tendon transfers: For longstanding deficits (e.g., latissimus dorsi transfer to improve external rotation).
• Free functional muscle transfer: Gracilis muscle transplanted with its nerve supply for severe total palsy.

Optimal timing:

• Upper‑trunk lesions – 3‑6 months.
• Lower‑trunk lesions – 6‑12 months (if no recovery).
• Complete palsy – individualized, often after 6‑12 months.

Medications

• Analgesics (acetaminophen or ibuprofen) for pain during therapy.
• No specific pharmacologic agents reverse nerve damage; steroids are not routinely recommended.

Adjunct Therapies

• Constraint‑induced movement therapy (CIMT) – briefly restricting the healthy limb to encourage use of the affected arm (usually after 12 months).
• Functional electrical stimulation (FES) – may assist in early muscle activation.

Living with Obstetric Brachial Plexus Injury

Families often wonder how to incorporate care into daily life. Below are practical tips.

Home Exercise Program

1. Perform gentle passive shoulder stretches (abduction, external rotation) for 5‑10 minutes, 3‑4 times daily.
2. Encourage “tummy time” with the affected arm placed under a rolled towel to promote active reaching.
3. Use toys that require bilateral hand use (soft blocks, textured books) to stimulate movement.
4. Monitor for signs of tightness or contracture – increased resistance or reduced range.

Feeding & Sleep

• When breastfeeding, support the infant’s head and shoulder to avoid excessive traction.
• Use a “pump‑and‑bottle” strategy if the infant has difficulty latching due to weakness.
• Position the infant on the unaffected side for sleep, but change sides frequently to avoid shoulder subluxation.

School & Social Activities

• Work with school occupational therapists for adaptive equipment (e.g., pencil grips, modified scissors).
• Encourage participation in swimming – water buoyancy reduces weight‑bearing stress while promoting arm movement.
• Discuss psychosocial impact; peer support groups can reduce anxiety.

Long‑Term Monitoring

• Annual orthopedic follow‑up until skeletal maturity to assess for glenohumeral dysplasia.
• Assess growth of the affected limb; significant discrepancy may need orthopedic lengthening procedures.
• Functional outcome measures (Malone scale, Pediatric Outcomes Data Collection Instrument) help track progress.

Prevention

While not all cases are avoidable, several strategies can lower the risk of OBPI.

• Antenatal care: Optimize maternal glucose control in diabetic pregnancies to reduce macrosomia.
• Appropriate labor management: Early recognition of shoulder dystocia and use of the McRoberts maneuver, suprapubic pressure, and delivery of the posterior arm before applying excessive traction.
• Limit traction: Avoid pulling on the umbilical cord unless absolutely necessary; consider “hands‑off” techniques when the head delivers spontaneously.
• Consider elective cesarean: In cases of known large fetal size (>4,500 g) or previous OBPI, a planned C‑section can reduce dystocia.
• Training for birth attendants: Simulation‑based drills improve response to shoulder dystocia and reduce harmful force.

Complications

If untreated or inadequately managed, OBPI can lead to several long‑term problems.

• Permanent muscle weakness or paralysis – limiting activities of daily living.
• Joint contractures – especially at the shoulder (adduction, internal rotation) and elbow (flexion).
• Glenohumeral dysplasia: Improper development of the shoulder socket, leading to arthritis in adulthood.
• Secondary scoliosis: Asymmetrical muscle tone can affect posture.
• Neurogenic pain: Neuropathic pain may develop in the affected limb.
• Psychological impact: Body‑image concerns, functional limitations, and reduced quality of life.
• Upper‑limb length discrepancy: Chronic under‑use may affect growth.

When to Seek Emergency Care

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References

1. Mayo Clinic. Brachial Plexus Injury. Accessed May 2026.
2. CDC. Birth Injuries: Brachial Plexus. 2023.
3. American Academy of Pediatrics, Committee on Fetus and Newborn. “Management of Brachial Plexus Birth Injuries.” Pediatrics. 2022;149(2):e2021055435.
4. National Institute of Neurological Disorders and Stroke. Brachial Plexus Injury Information Page. 2024.
5. World Health Organization. Birth Injuries. 2023.
6. Cleveland Clinic. Brachial Plexus Injury. Updated 2024.

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