Updated: 12/27/2021

Thoracic Outlet Syndrome (TOS)

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  • Snapshot
    • A 40-year-old man presents with difficulty grasping his tennis racket. The patient reports difficulty with maintaining a strong grip on his racket. This symptom is accompanied by numbness and tingling. On physical exam, there is atrophy of his intrinsic hand muscles.
  • Introduction
    • Clinical definition
      • syndrome resulting from compression/obstruction of the lower trunk of the brachial plexus and subclavian vessels as it passes through the thoracic outlet
        • the thoracic outlet is above the first rib and behind the clavicle
        • classified into three types
          • neurogenic (compression of brachial plexus)
          • arterial (obstruction in arteries)
          • venous (obstruction in veins)
  • Epidemiology
    • Demographics
      • adults
  • Etiology
    • Bony
      • cervical rib
        • an extra rib arising from 7th cervical vertebra
      • rudimentary first rib
    • Soft tissue
      • fibrous band from first rib to tip of C7 transverse process
      • hypertrophy of nearby muscles
        • more commonly in weight lifters or athletes
      • Pancoast tumor causing compression
      • cysts
    • trauma
    • Pathogenesis
      • compression of brachial plexus can cause neuropathies
      • compression of subclavian vein or artery can cause edema
  • Presentation
    • Symptoms
      • neurogenic
        • difficulty grasping or gripping
        • numbness and tingling in ulnar distribution
        • pain or weakness with elevation or repetitive use of the affected arm
      • arterial
        • claudication
        • diffuse arm and hand pain
        • fatigue and ache, especially after exertion of muscle
      • venous
        • upper extremity swelling
        • diffuse arm or hand pain
    • Physical exam
      • careful neurovascular exam should be performed
      • neurogenic
        • atrophy of intrinsic hand muscles
        • decreased sensation in ulnar nerve distribution
        • reproducible pain with elevation of arms
      • arterial
        • pallor and cool upper extremities
        • weak or absent radial or ulnar pulse
        • may have decreased blood pressure in the affected arm
      • venous
        • edema
        • cyanosis of upper extremity
        • distended veins
  • Imaging
    • Radiographs
      • indication
        • may reveal bony abnormalities
      • findings
        • cervical or rudimentary first rib
        • Pancoast tumor
    • Magnetic resonance imaging (MRI)
      • indication
        • may reveal soft tissue abnormalities
    • Ultrasound
      • indication
        • if vascular TOS is suspected
      • findings
        • vascular compression
    • Angiography
      • indications
        • if vascular TOS is suspected but ultrasound is unrevealing or further clarification is needed
      • findings
        • compression
  • Studies
    • Making the diagnosis
      • most cases are clinically diagnosed
  • Differential
    • Other causes of vascular compromise, such as emboli
      • distinguishing factor
        • pain worsened with exertion of the affected muscle and relieved with rest
  • Treatment
    • Conservative
      • physical therapy
        • indication
          • for all patients
    • Medical
      • nonsteroidal anti-inflammatory drugs (NSAIDs)
        • indication
          • pain management
      • anticoagulation
        • indication
          • patients with suspected thrombosis causing compression
    • Operative
      • surgical decompression
        • indications
          • patients with fibrous band
          • patients with cervical rib
          • pain refractory to conservative management
  • Complications
    • Aneurysm formation (post-stenotic)
    • Thromboembolism
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