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Thoracic Outlet Syndrome
From WikiSM
Other Names
- Neurogenic thoracic outlet syndrome
- Arterial thoracic outlet syndrome
- Venous thoracic outlet syndrome
- Vascular thoracic outlet syndrome
Background
- 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
History
Epidemiology
- 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]
Pathophysiology
- 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.
- Congenital - Presence of cervical rib, anomalous first rib, elongated transverse process
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
Evaluation
Radiographs
- Standard Cervical Spine Radiographs
- Evaluate for
- Cervical first rib
- Prominent ribs or transverse processes
- Fracture calluses
- Compressive tumors
Ultrasound
- 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
MRI
- Should be obtained on cervical spine or brachial plexus for neurogenic TOS
- Indications: usually profound weakness, failure to improve with conservative management
EMG/NCS
- Nerve conduction studies sometimes performed and are frequently normal
Other
- 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]
Classification
- Neurogenic thoracic outlet syndrome
- Venous thoracic outlet syndrome
- Arterial thoracic outlet syndrome
Management
- 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
- Asymptomatic patients without evidence of arterial degeneration may be managed nonsurgically with serial arterial ultrasound every 6 months
- Approached in similar manner and dependent on severity of complications
- Venous TOS
Complications
- Pneumothorax, wound infection, hematoma and hemothorax
- Potential for arterial, venous or nerve root injuries (rare)
See Also
References
- ↑ 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.
- ↑ Freischlag J, Orion K. Understanding thoracic outlet syndrome. Scientifica (Cairo). 2014;2014:1–6.
- ↑ Hangge, Patrick, et al. "Paget-Schroetter syndrome: treatment of venous thrombosis and outcomes." Cardiovascular diagnosis and therapy 7.Suppl 3 (2017): S285.
- ↑ 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.
- ↑ Kuhn JE, Lebus GF, Bible JE. Thoracic outlet syndrome. J Am Acad Orthop Surg. 2015;23(4):222–32.
- ↑ Povlsen B, Hansson T, Povlsen SD. Treatment for thoracic outlet syndrome. Cochrane Database Syst Rev. 2014.
- ↑ 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
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Last edited:
31 August 2023 18:46:47
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