Brachial Plexus Palsy: Causes, Classification, and Management

The brachial plexus is a network of nerves (C5-T1) originating from the spinal cord, passing through the neck, axilla, and into the arm, controlling motor and sensory function of the upper limb. Injury to this network—brachial plexus palsy—causes weakness, paralysis, and sensory loss, with profound functional impact.

Etiology

• Birth trauma (Neonatal BPP): 1-3/1000 live births. Shoulder dystocia → stretch injury (Erb's palsy: C5-C6; Klumpke's: C8-T1; Total: C5-T1).
• Trauma (Adult): Motorcycle/bike accidents (traction), MVCs, falls, penetrating wounds, gunshot.
• Iatrogenic: Central line placement (subclavian), first rib resection, neck dissection.
• Tumors: Pancoast tumor (lung apex), neurofibroma, schwannoma, metastasis.
• Radiation-induced: Delayed (months-years) fibrosis after chest/breast/neck RT.
• Inflammatory/immune: Parsonage-Turner syndrome (neuralgic amyotrophy) — acute severe shoulder pain followed by patchy weakness.

Clinical Presentation

• Weakness/paralysis in specific myotomes (e.g., C5-C6: shoulder abduction, elbow flexion, external rotation).
• Sensory loss in corresponding dermatomes.
• Diminished/absent reflexes (biceps, brachioradialis, triceps).
• Pain (neuropathic, often severe in traumatic/radiculitic).
• Horner's syndrome (ptosis, miosis, anhidrosis) → indicates preganglionic (root) avulsion (T1).
• Winging of scapula (long thoracic nerve/C5-C7).

Diagnostic Workup

• EMG/NCS (3-4 weeks post-injury): Localizes lesion, distinguishes pre- vs. postganglionic, assesses severity, reinnervation.
• MRI (T2-weighted, STIR, DTI): Visualizes root avulsions (pseudomeningocele), plexus morphology, tumors.
• CT Myelography: Gold standard for root avulsion (if MRI equivocal).
• Imaging for trauma: CXR (first rib, pneumothorax), CT angiogram (vascular injury).

Management

Neonatal BPP

• Early PT: Passive ROM, prevent contractures, parent education.
• Surgical referral by 3-6 months if no recovery (biceps function). Options: Neurolysis, nerve grafts, nerve transfers (Oberlin, Spinal Accessory → Suprascapular), free muscle transfer (late).
• Recovery: ~70% spontaneous (Erb's); total plexus worse.

Adult Traumatic

• Early exploration (3-6 months) for root avulsions, sharp transections, no clinical/EMG recovery.
• Nerve grafts (sural), nerve transfers (double fascicular for elbow flexion, spinal accessory → suprascapular for shoulder abduction).
• Late reconstruction: Tendon transfers, free functional muscle transfer (gracilis).

Non-Traumatic (Parsonage-Turner, Radiation)

• Pain management (neuropathic agents), PT, time. Surgery rarely indicated.

Prognosis Factors

• Injury type (avulsion worst, stretch best)
• Time to intervention
• Age (younger better)
• Level (proximal worse)
• Completeness

Brachial plexus injury demands urgent, multidisciplinary evaluation (neurosurgery, neurology, PM&R, PT/OT, pain). Early referral to a peripheral nerve center maximizes reconstructive options.