Pain, numbness and/or tingling, and heaviness of the involved upper extremity are common complaints reported by a patient with thoracic outlet syndrome (TOS). Often, the symptoms are vague and generalized. The entire extremity may be involved; additionally, neck pain and headaches are reported concomitantly.
Symptoms may begin insidiously after repetitive or stressful activity, such as prolonged computer keyboard use or mechanical and overhead work. Trauma, such as an automobile accident with occurrence of a whiplash injury, also has been associated with onset of TOS with a frequency of up to 23%. Sports activities, especially throwing and swimming, have been implicated as well; symptoms may be similar to those of a clavicular fracture, with a delayed onset from hours to weeks.
Autonomic phenomena (eg, cold hands, blanching, swelling) also may be reported. The proximity of the stellate ganglion to the first rib articulation, which is often dysfunctional or restricted in TOS, has been postulated as a cause.
Physical
A careful neurologic and musculoskeletal examination is essential to diagnose thoracic outlet syndrome (TOS) adequately. Often, the most important aspect of the physical examination is to diagnose or rule out other problems of the neck and arm.[9, 10]
The mainstay of the physical examination diagnosis of TOS involves the so-called stress tests (or provocative maneuvers) (see the images below). The sensitivity and specificity of these tests have been low in the studies on TOS completed to date. Different techniques for performing and interpreting these tests are discussed in the literature and vary even more in the bedside clinical situation.
Scalene focal (left) and regional (right) stress tests for thoracic outlet syndrome. Both tests can be easily combined to enhance the stress effect (may be helpful in mild cases).
Pectoral focal (left) and regional (right) stress tests for thoracic outlet syndrome.
The most common tests are the Adson maneuvers, where the head is placed in extension and side bending while the patient takes a deep breath and holds it, followed by rotation to stretch or tether the plexus and/or artery by the anterior and middle scalenes. The maneuver is held for 15-30 seconds while the clinician observes for onset of symptoms and obliteration of the pulse. Symptoms have been reported to the side of bending and, more commonly, to the side away from bending. If the symptoms are reported on the side of bending, then this finding overlaps with the Spurling sign, commonly used to assist in the diagnosis of cervical radiculopathy. Some examiners ask the patient to pull the head forward while maintaining the test position, causing the anterior scalene to contract against the plexus to enhance the stress effect.
Hyperabduction of the involved arm also can be used to stress the outlet; however, this maneuver often causes symptoms and loss of pulse even in normal individuals and may be misleading. The area of compression with this maneuver is considered more distal and frequently located at the anterior humeral head and plexus, with tethering under the pectoralis minor muscle.
Costoclavicular bracing (military maneuver) closes the space between the clavicle and first rib and may reproduce symptoms.
Focal stress tests involve applying pressure directly to the anterior scalene or upper segment of the pectoralis minor. These tests are considered positive if symptoms are reproduced within 15-30 seconds. In addition, some authors have noted a positive Tinel sign (percussing over the plexus) as diagnostic for TOS.
The elevated arm stress test has been noted to be highly sensitive for TOS. The upper extremity is held in the "stick-'em-up" position with the arms abducted and elbows flexed (both at 90°) for 3 minutes, while the patient simultaneously and vigorously flexes and extends the fingers (grasp and release). This test is considered positive if the patient cannot complete the full 3 minutes. Unfortunately, this test is challenging even for individuals without neurovascular symptoms to complete; thus, it may have limited practical usefulness in most clinical situations. In one study, over 80% of patients with carpal tunnel syndrome presenting to an electrodiagnostic medicine laboratory had a positive elevated arm stress test results.
Careful observation for asymmetry of the upper chest wall may reveal clavicular irregularity consistent with prior fracture. A nontender hard mass over the middle third of the clavicle often is noted. Deformity from displaced fracture (with or without nonunion) or exuberant callus could be responsible for direct compression of the plexus. Pressure on the clavicle can reproduce or aggravate symptoms, especially when nonunion is present; motion can be detected between the fragments.
Physical Therapy
Modalities with deep heat (eg, therapeutic ultrasound), electric stimulation, superficial heat (eg, Hydrocollator packs), stretching exercises, postural correction exercises, and strength and endurance exercises are all useful or necessary components of thoracic outlet syndrome treatment. Ultrasound is the preferred modality as it is capable of heating deep muscular and soft-tissue structures, which is essential to increase elasticity and facilitate effective stretching and/or manipulation, especially for the scalenes (see the first image below) and pectoralis minor muscles (see the second image below). Ideally, ultrasound should be performed immediately before the stretching or manual treatment, since the deep tissues cool (from 41-42°C back to 37°C) within 20-30 minutes.
Stretching technique for the pectoralis minor muscle. Left: The patient has taken the slack out of the muscle. Center: He then rotates the body away from the side being stretched, increasing traction. Right: Maximum rotation and stretch effect are achieved slowly. Image courtesy of The Journal of the American Osteopathic Association
Sagittal plane posture of patient with thoracic outlet syndrome before (left) and after (right) treatment. Notice the release of the pelvis that occurred with the reduction in hyperlordosis, which allowed the shoulder girdle to drop back and open the thoracic outlet. Image courtesy of The Journal of the American Osteopathic Association
Mobilization and manipulation procedures (often performed by an osteopathic physician) usually are indicated and necessary to release tight contracted/restricted vertebral segments and soft tissue (myofascial) regions, especially the anterior/middle scalenes (see the first image below) and pectoralis minor muscle (see the second image below) entrapment sites. Ultrasonography has been used to identify the pectoralis minor and guide the manipulating hand as an aid for more precise targeting and effective manual release of the muscle.[4]
Myofascial release technique for the scalene muscles. Left: Side-lying approach. Right/top: Supine approach with pillow under thorax. Right/bottom: Supine approach with head extended off the table and supported by the operator's knees. Image courtesy of The Journal of the American Osteopathic Association
Stretching technique for the scalene (anterior and middle) muscles. Left: The arm on the side to be stretched is secured down (hooked under the seat) to allow more control and effective stretch. Center: The opposite hand wraps partially around the head for good control to assist with the stretch. Right: After proceeding as far as tolerated, the patient leans the whole trunk away from the side being stretched, creating additional traction (downward) on the muscle by the arm that is secured. Image courtesy of The Journal of the American Osteopathic Association
Spray and stretch with a vapo-coolant spray is an effective adjunct to the other modalities mentioned here. Note that the research-based scientific evidence for these modalities is limited.
Occupational Therapy
Work simplification and back protection techniques often are helpful. These educational tools are available from the occupational therapist, as well as from the physical therapist.
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