History
Because of complex etiology and absence of good diagnostic tests, patient history is important in TOS.
Pain
In common neurogenic TOS, pain is the most common and earliest complaint. Detailed history characterizing the patient's pain may lead to appropriate diagnostic and therapeutic plans.
Ask the patient to describe the pain location and type on a pain diagram (anterior/posterior and lateral view of human picture).
Pain, numbness, and/or tingling of the upper extremity are common presenting features of neurogenic TOS.
Sometimes the patient may report pain in the chest, neck, and/or face and even headache. [3]
Precipitating factors include repetitive or stressful activity, such as prolonged computer keyboard use or overhead work, which can provoke or intensify pain.
Most patients report a history of an automobile accident or work-related injury.
Alleviating factors may exist and may provide additional clues for possible etiologies.
Various terms can be used to describe quality of pain, but it is usually a dull aching type in neurogenic TOS.
Spreading or radiation of pain is also important in evaluation of neuropathic pain. If retrosternal pain (radiating pain from the intercostobrachial nerve, a branch of the T2 intercostal nerve) is noticed on the left side, it can be confused with pain of cardiac or pulmonary origin. [4, 5]
Use some type of rating system to evaluate pain severity or intensity with a degree of objectivity and reproducibility. Different types of pain scales may be used. Numerical scales are more useful and reliable. The Visual Analog Scale (VAS) is a commonly used numerical scale.
Arterial TOS often is associated with aching, fatigue, weakness, and pallor due to brachial ischemia.
Cold temperature always worsens symptoms.
Physical
Several physical exam findings can aid the diagnosis of thoracic outlet syndrome (TOS):
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Hyperabduction and depression of the shoulder may provoke symptoms in patients with TOS.
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Various stress tests or provocative maneuvers are used by the clinician to evaluate TOS. The sensitivity and specificity of these maneuvers have been reported to be low.
Wright maneuver: This maneuver requires the patient to hold the arms next to the ears. Paresthesias usually are noted down the medial scapular border and into lower trunk distribution.
Elevated-arm stress test: In this test, the patient keeps arms abducted with flexed elbows for 3 minutes while flexing and extending the fingers. Results are considered positive if the patient cannot do this for 3 minutes.
Hyperabduction test: The radial pulse is diminished after elevating the involved arm above the head.
Supraclavicular pressure test: With the patient seated, the examiner places their fingers on the upper trapezius and the thumb on the anterior scalene muscle and squeezes for 30 seconds. Results are positive if there is reproduction of pain or paresthesias.
Adson maneuvers: While the patient is in a sitting position, ask the patient to inspire deeply, hold his breath, and extend his neck. Then, turn the patient's head passively as far as possible toward one side and then the other. When the head is turned toward the unaffected side, or sometimes the affected side, obliteration of the radial pulse with a drop in blood pressure in the arm is considered a positive result. While turning the head in either direction, the pulse may disappear on both sides, but, on the affected side, a longer lag occurs in its return. During this maneuver, a bruit may develop that is best heard in the supraclavicular space. [6]
Military maneuver (ie, costoclavicular bracing): This maneuver provokes symptoms when the patient elevates the chin and pulls the shoulder joint behind in an extreme "attention" position. [7]
Cyriax release test: With the patient leaning back slightly, grasp the patient's arms below the elbows with the elbow held at 80 degrees of flexion and elevate the shoulder girdle for up to 3 minutes. Results are positive if there is paresthesia, numbess, or reproduction of symptoms.
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In common neurogenic TOS, physical examination usually does not reveal appreciable sensory loss or motor atrophy in the limb.
Upper trunk involvement results in deltoid, upper arm, and medial scapular border pain.
Lower trunk involvement can cause dull ache in the medial forearm and paresthesias in the fourth and fifth fingers.
Tenderness to palpation over the brachial plexus and paresthesia on percussion may be observed (Tinel sign). Most patients demonstrate hypersensitivity to mechanical compression over the supraclavicular and infraclavicular fossae.
The Spurling sign (ie, pain during direct compression of the foraminal exit areas of cervical nerve roots) may help in making the diagnosis of cervical radiculopathy.
Vasomotor involvement caused by TOS must be differentiated from coexistent or other causes of vasomotor instability (eg, complex regional pain syndrome [reflex sympathetic dystrophy or causalgia]).
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In classic neurologic TOS, wasting (especially intrinsic hand muscle atrophy) is a characteristic feature. Signs of decreased pain and temperature sensation may be present in the C8 through T1 distribution.
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In arterial TOS, usual findings include cool and pale extremity. This finding depends on the extent of compression and injury to the subclavian artery.
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In venous TOS, the affected limb may be swollen and tender. It may exhibit cyanosis (dusky coloration), venous distension, and ischemic changes in the upper extremity. Strenuous physical activities of extremity can evoke these symptoms and signs. Venous thrombosis can develop at the site of compression.
Causes
The etiology of TOS varies. Most authors suggest that nonspecific neurologic TOS results from injury to the brachial plexus, by either traction or compression, at some point within the cervicoaxillary canal.
True (classic) neurologic TOS is caused by congenital anomalies and usually includes a taut fibrous band or rudimentary cervical rib. Other anatomic anomalies include elongated transverse process of C7.
Trauma or repetitive activities may produce TOS (eg, motor vehicle accident hyperextension injury, effort vein thrombosis).
Certain postures of the body may exacerbate or provoke the symptoms of TOS (eg, hyperabduction with external rotation of arm, depression of shoulder).
