Clinical Features and Treatment of Thoracic Outlet Syndrome:
The space at the thoracic outlet or inlet when it is less than adequate, subjects the neurovascular structures seeking to gain entry into the upper limbs via this space, to undue pressure. The blame for the neurovascular complaints should be placed at the doorstep of the decreased space and not at the structures producing the problems.
This syndrome results from the compression of neurovascular bundle comprising of subclavian artery and vein, axillary artery and vein and brachial plexus at the thoracic outlet. Thoracic outlet is a space between the first rib, clavicle, and the scalene muscles.
Sites of Compression
The sites of compression could be either Supraclavicular, Subclavicular or Infraclavicular.
- Supraclavicular: Interscalene triangle between the anterior scalene muscles.
- Subclavicular: Interval between the second thoracic rib, clavicle, and subclavius.
- Infraclavicular: Beneath an enclosure formed by the coracoid process, pectoralis minor, and costocoracoid membrane.
Rare Cause
Scissor-like encirclement of axillary artery by the median nerve.
Contributing Factors
Dynamic Factors
Arm when in full abduction pulls up the artery by 180 degree causing compression in the short retroclavicular space.
Static Factors
- Vigorous occupation: Increases the muscle bulk and thereby decreases the space.
- Inactive occupation: Decreases the muscle bulk and thereby increases the space.
- Congenital: Cervical rib decreases the interscalene space and thereby decreases the retroclavicular space.
- Traumatic: Malunion or nonunion of fracture clavicle.
Anomalies of the first thoracic rib.
Miscellaneous
- Tumor arising from the upper lobe of the lung.
- Cervicothoracic scoliosis.
- Abnormal variations of the scalene muscles.
Clinical Features
Obviously, this syndrome poses two major problems. The first one relates to the compression of the major vessels and secondly to the compression of the nerves.
1. Vascular Problems
Here the compression could be arterial or venous. During the arterial compression, which is mild in the early stages the patient complains of numbness of the whole arm with rapid fatigue during overhead exercises. If the compression is significant, the patient will complain of cold, cyanosis, pallor, and Raynaud’s phenomenon. Venous compression leaves the limb swollen and discolored after exercises, which disappears slowly with rest.
2. Neurogenic Problems
Patients complain of par esthesia along the medial aspect of the arm, hand, little and ring fingers. There is weakness of the hand also.
Complications
- Subclavian artery compression
- Results in poststenotic dilatation
- Stasis favors thrombosis
- The thrombi break and migrate distally causing embolization
Investigations
- X-ray Neck: To rule out intrinsic causes like cervical spondylosis, cervical rib, etc.
- Nerve Conduction Studies: Difficult to determine the nerve conduction velocity through the thoracic outlet, but its biggest value is to rule-out problems like entrapment, e.g. ulnar nerve at elbow, wrist, etc.
Treatment
- Conservative treatment: Consists of rest, physiotherapy, exercises like shoulder shrugging, etc.
- Surgical treatment
Thoracic Outlet problem is a number of conditions that happen when the veins or anxiety in the thoracic store — the area between your collarbone and your first rib — become compacted. This can cause discomfort in shoulder area and throat and pins and needles in your fingertips. Call now for best Physical Therapy: 703-205-1919