• Clinical science

Thoracic outlet syndrome

Summary

Thoracic outlet syndrome (TOS) is an umbrella term for conditions involving the compression of neurovascular structures (e.g., the brachial plexus or the subclavian artery or vein) as they pass from the lower neck to the armpit. Causes include trauma, tumors, or the presence of a cervical rib. Neurogenic TOS is the most common type and involves the compression of the brachial plexus, leading to neck pain and numbness and tingling in the fingers. Arterial TOS involves compression of the subclavian artery and presents with pain, pallor, coldness, and pulselessness in the affected arm, especially during overhead activities. Venous TOS results in pain, cyanosis, and swelling of the arm. Imaging techniques such as duplex sonography, X-ray, MRI, or electrodiagnostic testing are used to detect the cause of TOS. Mild symptoms should be treated with pain medication and physical therapy. Surgical resection of the causal structures might become necessary in the case of progressive neurologic dysfunction or acute vascular insufficiency.

Etiology

  • Compression of subclavian vessels and the lower trunk of the brachial plexus (mainly occurs within the scalene triangle) due to:
    • Physical trauma (e.g. hyperextension neck injuries)
    • Repetitive motion of the abducted and externally rotated shoulder; (e.g., tennis, baseball, swimming, repetitive throwing, carrying heavy objects overhead)
    • Structural abnormalities

Clinical features

Clinical features of TOS depend on the anatomic structure affected by compression and are more pronounced during and after overhead activity.

Swelling and venous distention in the arm may be a sign of venous thrombosis of the arm.

Diagnostics

  • Provocation tests
    • Adson test: a provocation test that is used to reproduce symptoms of TOS
      • Maneuver
        • The patient sits in a relaxed position while the examiner palpates the radial pulse.
        • Passive abduction of 90°; and lateral rotation and extension of the arm
      • Interpretation
    • Wright test: a provocation test used to reproduce paresthesia and changes in the radial pulse by performing the following maneuvers
    • Roos stress test: a provocation test used to reproduce symptoms of TOS
      • Maneuver: Both shoulders are positioned in abduction and are externally rotated at 90° angles, with elbows flexed at 90°, while the patient repeatedly makes a fist and then relaxes the hand.
      • Interpretation
        • Positive: sensation of heaviness or fatigue in affected limb
        • Negative: no change in sensation
  • Imaging
  • Other: depend on suspected underlying pathology

Treatment

  • In mild cases
  • Thoracic outlet decompression surgery: in cases of acute vascular insufficiency or progressive neurologic dysfunction or if conservative treatment fails
    • Transaxillary resection of the cervical rib or first rib
    • Angioplasty or venous/arterial bypass for severely narrowed vessels
  • 1. Fliegel BE, Menezes RG. Anatomy, Thorax, Cervical Rib. StatPearls. 2020. pmid: 31082045.
  • 2. Nichols AW. Diagnosis and management of thoracic outlet syndrome. Curr Sports Med Rep. ; 8(5): pp. 240–9. doi: 10.1249/JSR.0b013e3181b8556d.
last updated 10/26/2020
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