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Thoracic Outlet Syndrome

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Other Names

  • Neurogenic thoracic outlet syndrome
  • Arterial thoracic outlet syndrome
  • Venous thoracic outlet syndrome
  • Vascular thoracic outlet syndrome


  • Disorder that results in compression of neurovascular bundle exiting the thoracic outlet
    • thoracic outlet is an area of the neck defined as a space between the clavicle and first rib
    • Contains the brachial plexus, subclavian artery and subclavian vein
    • Compression causes symptoms that include upper extremity pallor, paresthesia, weakness, muscle atrophy and pain



  • Incidence difficult to discern with articles reporting incidence from 3-80/1000 [1]
  • Neurogenic thoracic outlet account for around 90% of cases [2]
  • Another study estimates 95% neurogenic, 4% venous and 1% arterial[3]


  • Usually grouped into congenital, traumatic or functionally acquired
    • Congenital - Presence of cervical rib, anomalous first rib, elongated transverse process
      • Muscular anomalies (scalenus anticus anomolies)
      • Fibrous anomalies (transversocostal, costocostal, etc.) are most common
    • Traumatic - whip-lash injuries and falls
      • Does not have to happen acutely and can progress over time after old injury
    • Functional acquired related to vigorous or repetitive activity related to sports or work
      • Typically overhead athletes or occupations with head or shoulders flexed anteriorly such as secretaries, computer operators, etc.

Risk Factors

  • Females more likely than males to be diagnosed with TOS
  • Most common ages diagnosed are between ages 20-50

Differential Diagnosis

  • Other brachial plexus injury
    • Brachial neuritis, Pancoast syndrome, radiation induced plexopathy, Parsonage-Turner syndrome
  • Cervical pain
  • Tunnel syndromes (carpal, cubital, radial)
  • Degenerative disease of glenohumeral joint, acromioclavicular joint, cervical spine
  • Non-compressive and peripheral neurologic disease

Clinical Features

  • History
    • Patients typically report (needs to be updated)
  • Physical Exam: Physical Exam Neck
    • Need to examine entire cervical spine and upper extremity
    • Inspect head and neck posture, looking for muscle atrophy
    • Observe skin color, temperature, hair distribution
    • Blood pressure can differ between arms
    • Shoulder and chest may have edema, pallor, visible collateral veins, bluish discoloration
    • Arterial TOS can have supraclavicular fullness or anuerismal pulsations
    • Motor strength of digits 1-3 is typically preserved
  • Slemonosky triad
    • Tenderness in the supraclavicular area
    • Weakness of the 4th and 5th digits
    • Hand paleness and/or paresthesias with elevation of the hands
  • Special Tests




  • Ultrasound maintains high sensitivity and specificity and is noninvasive and inexpensive (need citation)
    • Can also assess dynamic blood flow during compression maneuvers such as hyperabduction


  • Should be obtained on cervical spine or brachial plexus for neurogenic TOS
    • Indications: usually profound weakness, failure to improve with conservative management


  • Nerve conduction studies sometimes performed and are frequently normal


  • Prior gold standard arteriography and venography for vascular TOS (catheter-based)
    • Uncommonly used in modern medicine
  • Injection into the scalenes rarely used but can be helpful for diagnostic purposes in some cases [4]


  • Neurogenic thoracic outlet syndrome
  • Venous thoracic outlet syndrome
  • Arterial thoracic outlet syndrome


  • Depends on classification
    • Neurogenic TOS
    • Most cases treated initially with conservative management, although appropriate regimen controversial
      • Multimodal approach with patient education (postural mechanics, weight control, relaxation techniques), TOS-specific rehabilitation (active stretching, targeted muscle strengthening, activity modification) and pharmacologic therapy [5]
      • Pharmacologic management often provides symptomatic relief
        • NSAIDs and oral steroids used for neuropathic pain
        • Muscle relaxants, anticonvulsants and antidepressants occasionally used as adjuvants
        • Injection of local anesthetic, steroids or botulism toxin into anterior scalene/pectoralis have been used
    • Cases that fail conservative management for 4-6 months may be candidate for surgery if there is uncontrolled pain or progressive upper extremity weakness
      • Surgery of choice is first rib resection to decompress brachial plexus and can be performed by vascular surgeons (mostly), neurosurgeons, orthopedic surgeons and plastic surgeons.
      • Transaxillary, supraclavicular, and infraclavicular approaches used, with each having positive results with no definitively superior technique [6]
      • Scalenectomy and debridement of any fibrous bands often done depending on anatomy and symptoms
    • Venous TOS
      • Acute (<6 weeks) treated with anticoagulation, thrombolysis (catheter-directed), decompression by first rib removal and or/scalenectomy and venoplasty
      • Anticoagulation normally given for additional 3-6 months until venous patency confirmed with follow up imaging
        • Reports greater than 90 percent clinical success and less invasive methods such as robotic and thoracoscopic assisted techniques becoming more popular [7]
      • Chronic (> 6 weeks) with evidence of stenosis or occlusion treated with surgical decompression with first rib removal and or/scalenectomy
        • Thombolysis may be performed with total occlusion
        • Venoplasty can be used for residual subclavian stenosis
      • Intermittent without evidence of obstruction or occlusion may have trial of conservative management including limiting provocative position
        • Many have surgical decompression without anticoagulation or venoplasty
    • Arterial TOS
      • Approached in similar manner and dependent on severity of complications
        • Asymptomatic patients without evidence of arterial degeneration may be managed nonsurgically with serial arterial ultrasound every 6 months
          • No definitive guidelines exist
        • Surgical treatment when there is evidence of arterial complications such as intimal damage, mural thrombus, embolization, post-stenotic first rib or aneurysmal formation
        • Decompression with resection of cervical or first ribs, fibrous bands, scalenectomy and any other associated anomalies
          • Debate whether scalenectomy alone is as effective as first rib resection
        • Next step is arterial resection of the source of arterial embolus such as subclavian artery aneurysm or luminal stenosis
        • Digital revasculatization is the last step with vascular reconstruction in the form of primary anastomosis, interposition graft or axillary-brachial bypass to improve outflow of the limb


  • Pneumothorax, wound infection, hematoma and hemothorax
  • Potential for arterial, venous or nerve root injuries (rare)

See Also


  1. Citisli V. Assessment of diagnosis and treatment of thoracic outlet syndrome, an important reason of pain in upper extremity, based on literature. J Pain Relief. 2015;04(02):1–7.
  2. Freischlag J, Orion K. Understanding thoracic outlet syndrome. Scientifica (Cairo). 2014;2014:1–6.
  3. Hangge, Patrick, et al. "Paget-Schroetter syndrome: treatment of venous thrombosis and outcomes." Cardiovascular diagnosis and therapy 7.Suppl 3 (2017): S285.
  4. Narayanasamy N, Rastogi R. Thoracic outlet syndrome (TOS): an enigma in pain medicine. In: Kaye AD, Shah RV, editors. Case studies in pain management. Cambridge: Cambridge University Press; 2014. pp. 102–108.
  5. Kuhn JE, Lebus GF, Bible JE. Thoracic outlet syndrome. J Am Acad Orthop Surg. 2015;23(4):222–32.
  6. Povlsen B, Hansson T, Povlsen SD. Treatment for thoracic outlet syndrome. Cochrane Database Syst Rev. 2014.
  7. Jones, M.R., Prabhakar, A., Viswanath, O. et al. Pain Ther (2019) 8: 5
Created by:
John Kiel on 14 June 2019 08:33:10
Last edited:
31 August 2023 18:46:47