ADD-ONS / OTHER VASCULAR DISORDERS

Thoracic Outlet Syndrome (TOS)

Created 15/02/2022, last revision 10/01/2023

The anatomical condition of the upper thoracic aperture, with or without additional external factors, predisposes to chronic pressure damage of the brachial plexus and to vessels compression. This is particularly true for the caudal portion. Since exact pathogenetic mechanisms cannot always be proven, the general term thoracic outlet syndrome (TOS) is used.

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Classification of Thoracic Outlet Syndrome

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Etiology

  • anatomical defects
    • cervical rib, ligamentous band between the spine and rib
  • faulty posture
    • drooping shoulders with anteflexion of the head
  • trauma
    • difficulties may occur with a delay
  • repetitive, monotonous work
    • working at the computer, working on a production line, working with prolonged hand-holding
    • sports (e.g., swimmers)
    • repetitive carrying of loads over the shoulder
  • pregnancy
    • due to the loosening of the joints, TOS may appear during pregnancy

Clinical presentation

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Diagnostic evaluation

Personal history, clinical examination, provoking tests

Scalene syndrome and cervical rib syndrome
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Costoclavicular syndrome
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Hyperabduction syndrome
  • caused by compression of the neurovascular bundle by pressing it against the coracoid process (processus coracoideus) and pectoralis minor muscle (m. pectoralis minor) during hyperabduction of the arm
  • onset usually during sleep; the arm is paralyzed and numb after awakening

Wright’s test (hyper abduction test)

  • head forward, while the arm is passively abducted and extended without tilting the head
  • the elbow is flexed no more than 45°; the arm is then held for 1 min (measure radial pulse and monitor patient symptoms onset)
  • the test is repeated with extremity in hyperabduction (end range of abduction)
  • positive test:  a decrease in the radial pulse and/or reproduction of the patient’s symptoms

Roos test (“elevated arm stress test” or “EAST”)

  • hyperabduction of both upper limbs with elbows held at shoulder level and repeated wrapping and closing of the hand in a fist
  • positive test: 
    • a decrease in the radial pulse and/or reproduction of the patient’s symptoms
    • increasing pain at the neck and shoulder, progressing down the arm
    • paresthesias in the forearm and fingers
    • arm pallor with the arm elevated, reactive hyperemia when the limb is lowered
Eden´s test (costoclavicular TOS syndrome)
Adsen´s test (scalene syndrome)
Wright´s and Roos test (hyperabduction syndrome)

Other examination methods

  • X-ray of the upper thoracic outlet
    • look for cervical rib
    • exclude other structural pathologies
  • dynamic DSA/CTA or the Doppler ultrasound (during provocation tests)
    • direct demonstration of artery compression and determination of its severity
    • detection of post stenotic dilatation, detection of intraluminal thrombi within the dilated segment
    • flow pattern changing during the provoking maneuver (ultrasound)
      • dampened flow in distal segments + high-resistence flow in the proximal subclavian artery

→ more about dynamic CTA here

  • MRI
    • can help to localize the site of plexus or subclavian artery compression
    • it can detect a fibrous band between the spine and the 1st rib or cervical rib
  • EMG
    • detects neuropathic changes
BIlateral cervical rib as a cause of Thoracic Outlet Syndrome
CT angiography in a patient with neurogenic TOS on the right side (green arrow - subclavian artery, red arrow - anterior scalene muscle)
CTA during provoking maneuver (Subiran, 2012)

Management

Conservative treatment

  • physiotherapy with the strengthening of corset and shoulder muscles, posture improvement  → see here
  • relaxation techniques
  • medication (non-steroidal anti-inflammatory drugs – NSAID)

Surgical treatment

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Thoracic Outlet Syndrome (TOS)
link: https://www.stroke-manual.com/thoracic-outlet-syndrome-tos/