Spinal accessory neuropathy

Background

Lateral neck, with accessory nerve seen between the sternocleidomastoid and trapezius muscles.

• CN XI which innervates the sternocleidomastoid and trapezius muscles
• Commonly removed during radical neck dissection for head and neck cancers

Causes

• Iatrogenic
  • Radical or modified neck dissection
• Trauma
• Stroke

Clinical Features

• Trapezius atrophy
• Weakness of shoulder abduction
• Scapular dyskinesis

Differential Diagnosis

Upper extremity peripheral nerve syndromes

Median Nerve Syndromes

• Carpal tunnel syndrome
• Pronator teres syndrome
• Anterior interosseous neuropathy

Ulnar Nerve Syndromes

• Ulnar neuropathy

Radial Nerve Syndromes

• Radial neuropathy at the spiral groove (ie. "Saturday night palsy")
• Posterior interosseous neuropathy

Proximal Neuropathies

• Suprascapular neuropathy
• Long thoracic neuropathy
• Axillary neuropathy
• Spinal accessory neuropathy
• Musculocutaneous neuropathy

Other

• Brachial plexopathy
  • Parsonage-Turner syndrome
• Cervical radiculopathy

Evaluation

• Usually a clinical diagnosis
• Positive scapular flip sign
• Outpatient EMG or nerve conduction studies

Management

• NSAIDs
• Shoulder sling
• Physical therapy
• Surgical repair

Disposition

• Discharge with neurology follow up

See Also

• Neurologic exam
• Peripheral nerve syndromes