What is Thoracic Outlet Syndrome?
The thoracic outlet is an anatomical space between the clavicle and the first rib in the lower neck, which allows several important neurovascular structures to pass. The structures include the brachial plexus, subclavian artery, and subclavian brain. Compression of these vessels causes multiple problems such as upper extremity pallor, paraesthesia, weakness, muscle atrophy and pain. Therefore, thoracic outlet syndrome may be defined as a group of diverse disorders that result in compression of the neurovascular bundle exiting the thoracic outlet.
What causes Thoracic Outlet Syndrome?
The pathophysiology of symptoms causing thoracic outlet syndrome can be categorised into neurogenic, venous, and arterial aetiologies. Additionally, they can be further categorised into congenital, traumatic, or functionally acquired causes. The causes of TOS vary, and can include abrupt movements, hypertrophy of the neck musculature, and anatomical variations in which the brachial plexus roots pass-through this musculature, oedema, pregnancy, repeated overhead movements, blocked blood vessels, or abnormal posture.
Examples of:
– Congenital: the presence of a cervical rib or an anomalous first rib
– Traumatic: most commonly include whip-lash injuries and falls
– Functional acquired causes: related to vigorous, repetitive activity associated with sports or work
Examination of thoracic outlet syndrome
|
TOS subtype |
History |
Examination |
|
Arterial TOS |
Claudication/rest pain of upper limb, excluding shoulder/neck Numbness, coolness, pallor |
Raynaud’s phenomenon Upper limb ischaemia, digital ulceration, peripheral embolisation Pulsatile mass ± bruit on auscultation Blood pressure differential >20 mmHg Positive EAST, ULTT, Adson’s test |
|
Venous TOS |
Pain with movement or at rest in upper limbs, shoulders, and chest Swelling and cyanotic discolouration |
Upper limb swelling Cyanosis Positive EAST, ULTT, Adson’s test
|
|
Neurogenic TOS |
Having pain in neck, trapezius, shoulder, arm, and chest, as well as headaches in the occiput Variable pattern upper limb weakness, numbness, paraesthesias |
Tenderness on palpation: scalene triangle, subcoracoid space Upper plexus (C5-C7): sensory disturbance of arm. Weakness/atrophy of deltoid, biceps, brachialis Lower plexus (C8-T1): sensory disturbances in the forearm and hand. Inability to flex the wrist & fingers due to weakness & atrophy of small muscles in the hand Positive EAST, ULTT, Adson’s test |
Diagnostic tests for thoracic outlet syndrome
|
Test |
Maneuver |
Positive test |
|
Adson maneuver |
The affected arm is fully extended at the shoulder and abducted 30°. The patient stretches his or her neck and inhales deeply as he or she turns the head toward the symptomatic shoulder
|
Decrease or absence of ipsilateral radial pulse
|
|
Wright maneuver |
The shoulder on the symptomatic side is abducted above 90° and externally rotated
|
Decrease or absence of ipsilateral radial pulse
|
|
Halsted maneuver |
Abduct, extend to 45°, and rotate the affected arm externally. A downward traction is applied to the arm, and the patient’s neck is turned away from the affected side
|
Decrease or absence of ipsilateral radial pulse
|
|
EAST (Roos test) |
With the arms in the surrender position, the shoulders are abducted 90 degrees and in external rotation and the elbows flexed to 90°. During this exercise, he opens and closes the hands for 3 min
|
Provoking pain, paresthesia, heaviness, or weakness
|
|
ULTT |
The following positions are possible: Position 1: Arms elongated at 90° with elbows flexed; Position 2: Active dorsiflexion of both wrists; Position 3: Head is tilted ear to shoulder in both directions
|
Symptoms are triggered on the ipsilateral side by positions 1 and 2, while the contralateral side is elicited by position 3.
|
Differential diagnoses for thoracic outlet syndrome and their distinguishing clinical features
– Raynaud’s syndrome: cold fingers, colour changes in the skin in response to cold or stress that are relieved by warmth
– Vasculitis: severe sudden-onset pain involving more than one limb, elevated C-reactive protein level, skin lesions
– Rotator cuff tear: pain during shoulder movement that is easily differentiated by ultrasound
– Cervical radiculopathy: acute pain (disc rupture), insidious onset (spinal stenosis), spurling sign (+), denervating potential of cervical paraspinalis on electromyography
– Cubital tunnel syndrome: Tinel sign (+) over cubital tunnel: differentiated by nerve conduction study
– Guyon’s canal syndrome: Tinel sign (+) over Guyon’s canal: differentiated by nerve conduction study
– Neuralgic amyotrophy: extreme sudden-onset pain followed by rapid motor weakness and atrophy
– Pancoast tumour: pain in the shoulder radiating to the inner part of the scapula, possible Horner syndrome, tumor on the apex of the lung
– Complex regional pain syndrome: diffuse pain, predominant vasomotor features, history of stroke, trauma, or peripheral nerve injury
Treatment/management of Thoracic Outlet Syndrome
Patients with TOS symptoms are relieved by conservative treatment and therapeutic strategies depending on the type of TOS the individual has. However, consensus on appropriate conservative therapeutic treatment methods is lacking. In rehabilitation therapy, the initial treatment strategies implemented are patient education on postural mechanics, relaxation techniques and weight control, exercise including stretching and strengthening of targeted muscles, and activity modification. For neuropathic pain, oral pain medications are often used. Thrombolysis with continuous infusion of a plasminogen activator is commonly used to treat venous TOS. The most effective treatment for arterial TOS is thrombolysis or embolectomy. The gold standard of treatment remains surgery to maximize function or preserve limb, and it is vital that future research clarifies the ideal pain and physiotherapy regimens, as well as novel approaches to neurovascular decompression.
Despite the different types of TOS, exercise has been shown to be a useful approach in 50-90% of all TOS cases. Symptoms of TOS generally improve with exercise and other physical therapy techniques. When treating TOS, a general exercise session might emphasize proper scapular function, breathing techniques, and head and pelvic alignment during various activities. The aim of resistance exercises is to achieve muscular endurance with low weight and a high number of repetitions. It is important to understand that strength training alone won’t alter the pathophysiology of TOS, but requires a combination of strengthening, stretching and postural adjustments.
A basic exercise program may include:
– Scapular retraction and depressions
– Standing shoulder external rotations
– Banded straight arm extension
– Prone shoulder extension/abduction/horizontal abduction
– Frontal and lateral raise
– Serratus push with DB
– Chin tucks
References
Chang, M. C., & Kim, D. H. (2021). Essentials of thoracic outlet syndrome: A narrative review. World Journal of Clinical Cases, 9(21), 5804. https://doi.org/10.12998/wjcc.v9.i21.5804
Jones, M. R., Prabhakar, A., Viswanath, O., Urits, I., Green, J. B., Kendrick, J. B., … & Kaye, A. D. (2019). Thoracic outlet syndrome: a comprehensive review of pathophysiology, diagnosis, and treatment. Pain and therapy, 8(1), 5-18. https://doi.org/10.1007/s40122-019-0124-2
Levine, N. A., & Rigby, B. R. (2018, June). Thoracic outlet syndrome: biomechanical and exercise considerations. In Healthcare (Vol. 6, No. 2, p. 68). Multidisciplinary Digital Publishing Institute. https://doi.org/10.3390/healthcare6020068
Ohman, J. W., & Thompson, R. W. (2020). Thoracic outlet syndrome in the overhead athlete: diagnosis and treatment recommendations. Current Reviews in Musculoskeletal Medicine, 13, 457-471. https://doi.org/10.1007/s12178-020-09643-x
Povlsen, S., & Povlsen, B. (2018). Diagnosing thoracic outlet syndrome: current approaches and future directions. Diagnostics, 8(1), 21. https://doi.org/10.3390/diagnostics8010021