What is the approach to diagnose and treat thoracic outlet syndrome?

Diagnosis and Treatment of Thoracic Outlet Syndrome

The diagnosis of thoracic outlet syndrome (TOS) should begin with chest radiography to identify osseous abnormalities, followed by ultrasound duplex Doppler to evaluate vascular compression, and MRI for neurogenic cases, with treatment progressing from conservative physical therapy to surgical intervention for cases with significant anatomical abnormalities or progressive symptoms. 1

Types of Thoracic Outlet Syndrome

TOS can be classified into three distinct types:

• Neurogenic TOS (95% of cases): Compression of the brachial plexus 2
• Venous TOS (4-5%): Compression of subclavian/axillary veins 3
• Arterial TOS (1%): Compression of subclavian artery 3

Diagnostic Algorithm

Step 1: Initial Imaging

• Chest Radiography: First-line imaging to identify:
  • Osseous abnormalities (cervical ribs, first rib anomalies)
  • Congenital osseous malformations
  • Previous surgical changes
  • Should be performed upright (malalignment can be underrepresented on supine radiography) 4, 1

Step 2: Physical Examination and Maneuvers

• Perform multiple provocative maneuvers (single tests lack sufficient sensitivity/specificity):
  • Adson's Test
  • Wright's Test
  • Eden's Test
• Check for diminished radial pulse indicating arterial compression 1
• Bilateral arm blood pressure measurement: A systolic blood pressure difference >25 mmHg between arms is significant 1

Step 3: Advanced Imaging Based on Suspected Type

For Suspected Vascular TOS:

• Ultrasound Duplex Doppler: Second-line imaging to:
  • Evaluate subclavian artery/vein compression
  • Assess changes in vessel diameter during arm abduction
  • Evaluate cross-sectional area of costocervical space with provocative maneuvers 4, 1
  • Perform in neutral position and with provocative maneuvers

For Suspected Neurogenic TOS:

• MRI without contrast: Best for evaluating:
  • Brachial plexus compression
  • Cervical spine pathology
  • Soft tissue masses 1
  • Allows dynamic evaluation of neurovascular bundles

For Suspected Vascular Complications:

• CT with IV contrast: More cost-effective than MRA/MRV to evaluate:
  • Thrombosis
  • Stenosis 1

For Diagnostic Confirmation in Neurogenic TOS:

• Ultrasound-guided anterior scalene muscle injection: Confirms diagnosis if symptoms are relieved following injection 1

Treatment Approach

Conservative Management (First-Line)

• Physical therapy and postural correction
• Anti-inflammatory medication
• Weight loss if applicable
• Strengthening exercises 1, 2
• Botulinum toxin injections may be considered 2

Surgical Intervention (For Refractory Cases)

Indicated for:

• Significant anatomical abnormalities
• Vascular TOS with complications
• Neurogenic TOS with progressive neurological deficits 1

Surgical Options:

• First rib resection
• Scalenectomy
• Cervical rib resection
• Vascular reconstruction when needed 1

Approach Selection:

• Transaxillary approach: Preferred for first rib excision
• Supraclavicular approach: Favored for scalenotomies
• Combined approach: When larger field of view is required 5

Specific Management for Venous TOS

• Urgent thrombolysis
• Anticoagulation
• Surgical decompression 6

Post-Treatment Rehabilitation

• Begin passive/assisted mobilization of the shoulder immediately post-surgery
• By 8 weeks postoperatively, patients can begin resistance strength training 2
• Post-surgical rehabilitation is critical for long-term success 1

Important Clinical Considerations

Diagnostic Pitfalls

• TOS is not a diagnosis of exclusion; there should be evidence for a physical anomaly that can be corrected 2
• Venous compression during arm abduction can be seen in asymptomatic individuals (71% may have bilateral venous compression on imaging but only 21% have bilateral symptoms) 4
• The most common site of neurovascular compression is the costoclavicular space 1

Surgical Complications to Monitor

• Injury to subclavian vessels (potentially leading to exsanguination)
• Brachial plexus injury
• Hemothorax
• Pneumothorax 2

Cost Considerations

• Chest radiography: ~$50-200
• Ultrasound duplex Doppler: ~$200-500
• MRI: ~$1000-2000 (consider only if absolutely necessary) 1