What is the purpose and management of the TOS (Thoracic Outlet Syndrome) test manoeuvre?

Thoracic Outlet Syndrome Test Maneuver: Purpose and Management

The TOS test maneuver is primarily used to diagnose thoracic outlet syndrome by reproducing symptoms through provocative positioning that compresses neurovascular structures in the thoracic outlet, guiding appropriate treatment decisions based on the type and severity of compression identified. 1, 2

Purpose of TOS Test Maneuvers

TOS test maneuvers are designed to:

1. Reproduce patient symptoms by compressing neurovascular structures in the thoracic outlet
2. Identify the specific type of TOS (neurogenic, venous, or arterial)
3. Determine the anatomical location of compression (interscalene triangle, costoclavicular space, or pectoralis minor space)
4. Guide appropriate treatment decisions based on findings

Common TOS Test Maneuvers

• Roos Test (Elevated Arm Stress Test): Patient holds arms abducted and externally rotated at 90° with elbows flexed at 90° while repeatedly opening and closing fists for 3 minutes. Reproduction of symptoms or inability to maintain the position indicates a positive test 3

• Adson's Test: Patient extends neck and rotates head toward the affected side while taking a deep breath. Examiner checks for diminished radial pulse, indicating arterial compression 1

• Wright's Test: Patient's arm is abducted and externally rotated while examiner checks for diminished pulse, indicating compression in the costoclavicular space 1

• Eden's Test: Patient's shoulders are drawn back and down while examiner checks for diminished pulse, indicating compression 1

Diagnostic Imaging Following Positive Test Maneuvers

After positive provocative maneuvers, the following imaging studies should be considered:

1. Chest Radiography: First-line imaging to identify osseous abnormalities such as cervical ribs, first rib anomalies, and congenital malformations 1, 2

2. Duplex Ultrasound: Excellent initial study for vascular TOS (arterial or venous) to assess:

   • Subclavian artery/vein compression
   • Dynamic blood flow during arm abduction
   • Changes in vessel diameter and peak velocity 1, 2
   • Can be performed with provocative maneuvers in real-time

3. MRI/MRA/MRV: Superior for neurogenic TOS evaluation:

   • Delineates brachial plexus anatomy
   • Identifies soft tissue causes of compression
   • Evaluates for space narrowing during provocative positioning 1

4. CT/CTA/CTV: Useful for evaluating:

   • Bony abnormalities
   • Space narrowing with provocative maneuvers
   • Vascular complications 1

Management Based on Test Results

Conservative Management (First-Line)

• Physical Therapy: Focused on scapular control, positioning, and movement restoration 2, 4
• Postural Correction: Address contributing postural deviations 4
• Targeted Strengthening: Isolated strengthening of weak shoulder muscles 4
• Manual Therapy Techniques: Including taping and other adjunctive approaches 4

Diagnostic Confirmation Procedures

• Scalene Muscle Injection: For suspected neurogenic TOS, ultrasound-guided anesthetic injection into the anterior scalene muscle can confirm diagnosis if symptoms are relieved 1

• Bilateral Arm Blood Pressure Measurement: A systolic blood pressure difference >25 mmHg between arms suggests vascular compression 2

Surgical Intervention (When Conservative Management Fails)

• Surgical Decompression: Recommended for cases with significant anatomical abnormalities or failed conservative management 2, 5

• Revascularization: Should be considered in symptomatic patients with TIA/stroke, coronary subclavian steal syndrome, or severe ischemia 2

• Endovascular Approaches: May be considered over open surgery due to lower complication rates in selected cases 2

Clinical Pearls and Pitfalls

• Pitfall: Relying on a single test maneuver. Multiple maneuvers should be performed as no single test has sufficient sensitivity or specificity 1, 3

• Pitfall: Positive imaging findings without symptoms. Compression during provocative positioning can be seen in asymptomatic individuals 1

• Pearl: The Roos test should be performed at least twice in patients with suspected TOS due to variable reliability of provocation maneuvers 3

• Pearl: TOS is rare but not insignificant, with neurogenic TOS occurring at approximately 2-3 cases per 100,000 people per year and venous TOS at 0.5-1 per 100,000 people per year 6

• Caveat: Symptoms reported during testing may differ from historical symptoms in up to one-third of patients 3