Dr. Ebraheim’s educational animated video describes the condition of thoracic outlet syndrome.
Thoracic outlet syndrome is a diagnosis of exclusion based on the patient history and symptoms. This can cause pain in the shoulders, neck and numbness in the fingers as the arm is moved.
The most common causes:
• Structures may be compressed in the thoracic outlet by the cervical rib
• Anomalies of the scalenus muscles
It is a neurovascular compression neuropathy of the brachial plexus in the thoracic outlet in the retroclavicular region with either a neurogenic or vascular etiology.
The thoracic outlet space is created by:
•Clavicle
•First rib
•Subclavius muscle
•Costoclavicular ligament
•Anterior scalene muscle
This space also contains the subclavian vessels and the thoracic duct. It also contains the lower trunk of the brachial plexus (C8, T1).
Two types:
1.Neurogenic
2.Vascular
The neurogenic type is caused by compression of the neurovascular bundle as it passes over the first rib or through the scalene muscle.
Causes of compression:
•Cervical rib
•Elongated vertebral transverse process (C7)
•Anomalies of the scalene muscle insertions
•First rib malunion
•Abnormal fibrous band on or near the two scalenous muscles
•Repetitive shoulder movement
•Extreme arm positions
•Abnormal pectoralis minor muscle
•Weight lifting
•Rowing
•Swimming
Vascular Entity: Caused by a compressed subclavian vessel or by an aneurysm.
Where is the compression site?
•Where the brachial plexus passes over the first rib.
oUsually at site of scalene triangle
oThe brachial plexus and subclavian artery pass through the triangle (subclavian vein does not pass through the triangle)
•Under the clavicle by the subclavius tendon
•Underneath the conjoined tendon inserting into the coracoid process
Diagnosis:
•Symptoms are usually vague
•Pain in the shoulder and neck that usually radiates to the forearm and hand (paresthesia radiating along the arm)
•Loss of sensation of the little and ring fingers
•May be some vascular symptoms such as arterial ischemia, venous congestion, Raynaud’s phenomenon (changing colors of the hands or chronically reduced pulse)
•Look for ulnar nerve sensory changes and intrinsic weakness
•Look to see if the patient has intolerance to cold (Raynaud’s phenomenon)
Differential Diagnosis:
•C8 radiculopathy or ulnar nerve compression at the elbow
oCombination of weakness involving the median and ulnar nerve innervated muscles may confirm a more proximal injury to the brachial plexus
•Rule out double crush syndrome with carpal tunnel syndrome and thoracic outlet syndrome
Compression of the medial antebrachial cutaneous nerve could occur with compression of the thoracic outlet.
Provocative Tests: have a high rate of false positives and are of limited clinical value if used alone.
•Adson’s Test
oMost commonly used test
oAbduct, extend and externally rotate the arm while feeling the radial pulse
oRotate the head towards the tested arm and may also extend the neck
oDecreased interscalene space by tensing of the middle and anterior scalenus muscles
oThis test is positive if the pulse disappears with reproduction of the symptoms
oRadial pulse obstruction is not specific
•Wright Test
oAbduction, external rotation of the arm with the neck rotated away that will lead to the loss of pulses and reproduction of symptoms
•Roos Test (Elevated Arm Stress Test” or “EAST”)
oElevated arm stress test
oRaise both arms up and hold this position for one minute
oOpen and close the fingers for three minutes while holding them overhead
oTest is positive if there is reproduction of pain and numbness of the shoulders as well as fatigue
Imaging
•Cervical spine may show a cervical rib
•Chest x-ray may show a Pancoast tumor (apical lung tumor) that could put pressure on the brachial plexus causing ulnar nerve symptoms
EMG and Nerve Studies
•Results are usually not very helpful
Vascular Studies
•May identify a vascular form or thoracic outlet syndrome
Treatment
•Physical therapy
oStrengthen the shoulder girdle muscles
oThis is usually the first form of treatment
•Maintain proper posture
•Activity modification
•Correction of postural imbalances is needed
•Surgery
oDecompression is indicated in cases of intractable pain, neurological deficit, or persistent vascular insufficiency in addition to failure of nonoperative treatment
oResection of the first rib or cervical rib if present
oRelease or excise the anterior and middle scalene muscles
oExcision of any abnormal structures
oSurgery can be done through a transaxillary or supraclavicular approach
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22 июл 2024
