Chest outlet pressure syndrome is a medical condition characterized by the compression of nerves or blood vessels between the neck and shoulder, within the area referred to as the chest outlet. This compression often leads to pain in the shoulder and neck, along with potential numbness in the fingers.

Various factors can contribute to thoracic outlet syndrome, including physical trauma like car accidents, repetitive strain from work or exercise, and even anatomical abnormalities such as extra or misshapen ribs. The exact cause of this syndrome is sometimes unknown.

Treatment typically involves a combination of physical therapy and pain management, with many patients experiencing improvement following these interventions. In some cases, surgical options may be recommended.

What is thoracic outlet syndrome?

Thoracic outlet syndrome, or simply TOS, is a general term that describes several conditions associated with compression of nerves and blood vessels in the area of ​​the thoracic outlet, which represents the upper outlet of the chest cavity.

Types of thoracic outlet syndrome: –

• Neural TOS (nTOS): The most common form is about 80-85% of cases.  

The pressure affects the brachial plexus and symptoms develop due to nerve pressure.

• Venous thoracic outlet syndrome (vTOS): Much less common in about 10-15% of cases.

The pressure affects the subclavian vein and symptoms develop due to insufficient blood return from the arm.

• Arterial thoracic outlet syndrome (aTOS): Less common form in about 1-2% of all cases.  

The pressure affects the subclavian artery and symptoms develop as a result of insufficient flow to the affected arm.

How common is thoracic outlet syndrome?

Thoracic outlet syndrome is a rare musculoskeletal condition, making it difficult to determine its exact prevalence due to varying diagnostic criteria and lack of recognition. 

The estimated impact of TOS falls between 3 and 80 individuals per 100,000 in the general population.

Neurogenic TOS (compression of brachial plexus nerves) is more common than vascular TOS.

TOS is commonly diagnosed in women compared to men, typically affecting people aged 20 to 50, although it can occur at any age. 

Accurate diagnosis and proper management are crucial for individuals suspected of TOS due to the broad range of symptoms and potential contributing factors.

What can mimic thoracic outlet syndrome?

The signs of thoracic outlet syndrome can be mimicked by various conditions, posing challenges in diagnosis. 

Among the conditions that can mimic TOS are:

1. Cervical Disc Herniation: When discs in the cervical spine herniate, they can compress nerves or blood vessels, resulting in arm pain, numbness, and weakness similar to those of TOS.
2. Brachial Plexopathy: Damage or compression of the brachial plexus outside the thoracic outlet can lead to symptoms resembling neurogenic TOS, such as arm pain, numbness, and weakness.
3. Rotator Cuff Injury: Injuries or inflammation of the rotator cuff muscles or tendons in the shoulder can cause arm pain and weakness that may be misinterpreted as TOS.
4. Peripheral Nerve Entrapment: Compress or entrapment of peripheral nerves in the arm, like the ulnar nerve (cubital tunnel syndrome) or median nerve (carpal tunnel syndrome), can present symptoms akin to TOS.
5. Vascular Conditions: Conditions affecting blood vessels, such as arterial compression, aneurysms, or blood clots, can exhibit symptoms of arm pain, swelling, and discoloration, which can overlap with vascular TOS.
6. Myofascial Pain Syndrome: Chronic muscle pain and trigger points in the neck, shoulder, or chest muscles can imitate TOS symptoms, including referred pain, numbness, and arm tingling.
7. Fibromyalgia: Characterized by widespread musculoskeletal pain, fatigue, and tenderness, fibromyalgia can sometimes show symptoms similar to TOS.
8. Psychological Factors: Conditions like anxiety or depression can manifest with somatic symptoms, such as arm pain and discomfort, which might be misidentified as TOS.

Given the symptom overlap and diverse contributing factors, an accurate TOS diagnosis necessitates a comprehensive clinical assessment. 

This includes a detailed medical background review, physical examination, and various diagnostic tests like imaging studies or nervous conduction studies. 

A multi-faceted approach involving healthcare professionals from different disciplines, such as orthopedics, neurology, and physical therapy, may be essential to distinguish TOS from other conditions and devise an appropriate treatment strategy.

What are the symptoms of thoracic outlet syndrome?

Signs of thoracic outlet syndrome can vary, depending on the structures compressed.  

When nerves are compressed, signs and symptoms of neurogenic thoracic outlet syndrome include:

• Muscle wasting such as shoulder muscles and at the fleshy base of the thumb (Gilliat-Sumner hand).
• Numbness or tingling in the arm or fingers.
• Pain or soreness in the neck, shoulder, or hand.
• Poor grasping of objects.

Signs and symptoms of vascular thoracic outlet syndrome can include:

• Hand discoloration (bluish color).
• Pain and swelling in the arm or hand, perhaps due to blood clots.
• Blood clots and blood flow in the veins or arteries in the upper part of the body.
• Lack of color (pallor) in one or more of your fingers or your entire hand.
• Weak or no pulse in the affected arm.
• Cold fingers, hands, or arms.
• Arm fatigue with activity.
• Numbness or tingling in the fingers.
• Arm and hand or neck weakness.
• Feeling a throbbing mass near the collarbone.

What are the causes of thoracic outlet syndrome?

In general, thoracic outlet syndrome is caused by compression of nerves or blood vessels in the thoracic outlet, just below the collarbone.  

The cause of compression varies and can include:

• Anatomical abnormalities.

Genetic abnormalities that are present at birth (congenital) can include an extra rib located above the first rib (cervical rib) or an abnormality of the tough, fibrous bundle that connects the spine to the rib.

• Bad body posture. 

Dropping the shoulders or holding the head forward can cause compression of the thoracic outlet area.

• Accidents.  

Traumatic accidents, such as car accidents, can lead to internal changes that then put pressure on the thoracic outlet nerves.  

The onset of symptoms associated with traumatic accidents is often delayed.

• Repetitive activities.  

Doing the same things repeatedly can damage your body’s tissues over time.  

A person may notice symptoms of chest out syndrome if the job requires constant repetition of a movement, such as typing on a computer keyboard, constantly working on an assembly line, or lifting objects above head level, as is necessary when storing goods by placing them on shelves.  

Athletes, such as baseball pitchers and swimmers, can also develop thoracic outlet syndrome due to years of repetitive motion.

• Pressure on joints.

Obesity can increase the amount of stress on the joints, as can be caused by carrying and walking an excessively heavy bag or backpack.

• Pregnancy.  

Because the joints loosen during pregnancy, signs of thoracic outlet syndrome can appear for the first time during pregnancy.

How to diagnose thoracic outlet syndrome?

If it is believed that the patient has this disease, some tests are performed.  After the physical examination, MRI, electromyogram, and CT examinations are performed.  A sunken shoulder, long neck, and horizontal clavicle are noted on examination.  

If the finger is pressed against the patient, pain appears to occur.  

This disease is more common in musicians who play stringed instruments.  

Among the clinical tests conducted:

• Adson’s test:

Stand behind the patient, holding the patient’s shoulder with one hand and the wrist with the other.  

A radial pulse is heard at the wrist.  

His arm is raised to a certain position.  The head is brought to the side for examination, a deep breath is taken and the patient is asked to hold his breath.  If there is pressure, the radial pulse cannot be taken or weakness is felt.  This is called a positive (+) test result.

• Clavicle-thoracic test:

This is called a military posture test.  

Chests are puffed out and shoulders are pushed back.  In this position, if there is pain in the arm when the first cost is directed upward, a decreased radial pulse or no pulse indicates that the test is positive (+).

• Hyperabsorption test:

The arm is raised to a 180-degree position in the test.  Thus, it is brought closer to the first coast.  Again, try taking the radial pulse.  If the pulse decreases or disappears, the (+) test is positive.

What is the treatment of thoracic outlet syndrome?

• Physical therapy and exercise.
• Nonsteroidal anti-inflammatory drugs and sometimes antidepressants.
• Sometimes surgical treatment is.

For most people with symptoms of thoracic outlet syndrome, physical therapy and exercise lead to improvement. 

Low doses of nonsteroidal anti-inflammatory drugs (NSAIDs) and antidepressants may also help.

Surgery may be necessary if an anatomical abnormality or pressure on large blood vessels is confirmed, or if symptoms continue to worsen. However, it is difficult to make a definitive diagnosis, and symptoms often persist after surgery.

• Surgical intervention:

The surgeon approaches the plexus brachialis and subclavian vessels from the front.  An incision is made above the collarbone (clavicle bone) and the surgeon continues to expose and manipulate the plexus brachialis.  

The main drawback of this approach is the limited ability to detect and manipulate the deep parts of the plexus brachialis.  Also, removing the first rib requires significant skill to the brachial plexus which may result in temporary or permanent damage.

• Lateral intervention:

The surgeon approaches the thoracic outlet from the axilla.  

Typically, this approach is preferred by thoracic surgeons.  

Provides sufficient exposure to remove the middle portion of the first rib. Therefore vascular TOS (arterial and venous) can be treated effectively.  

The posterior section of the first rib is difficult to reach in this way, and therefore TOS treatment is repeated with this type of surgery.

• The best procedure:

Doctors have developed a unique posterior approach that allows complete removal of the first rib and decompression of all nerves and vessels involved.  

Some surgeons consider it the most effective method for treating thoracic outlet syndrome.  

Another important advantage of the new technology is that we have a high level of safety.  

Compared to other techniques, it has the unique advantage of being the least risky.  

An increasing number of patients have been treated with the new method and no recurrence has been observed so far.

How is surgery performed?

The surgery is performed behind the shoulder and provides exposure to all plexus brachialis nerves and subclavian vessels.  

The incision is about 5 cm (2 inches) and the patient is discharged on the second or third day after surgery.  

Patients are advised to avoid excessive use of the arm for one month.  

The usual recovery period is about 3 months.