Thoracic Outlet Syndrome (TOS) is a complex and controversial condition in which the nerves and/or blood vessels in the thoracic outlet are compressed. The thoracic outlet is the area between the base of the neck and the armpit, including the front of the shoulders and chest.
The term ‘thoracic outlet syndrome’ was originally coined in 1956, to indicate compression of the neurovascular structures in the interscalene triangle. Since then, the condition has emerged as one of the most controversial topics in musculoskeletal medicine and rehabilitation. This controversy extends to almost every aspect of the condition, including the definition, the incidence, the pathoanatomical contributions, diagnosis and treatment.
TOS affects mainly the upper limbs, with signs and symptoms manifesting in the shoulders, neck, arms, hands and sometimes fingers. In rare cases, the condition can lead to eye and vision problems.
Symptoms of TOS
Due to the many variations in cause and symptoms, TOS is a clinical controversy.
The National Center for Biotechnology Information reports that TOS is a frequently overlooked peripheral nerve compression that creates difficulties for the clinician regarding diagnosis and management.
The symptoms of TOS range from an aching pain in the neck, shoulder, arm, or hand, as well as pain, numbness, or tingling in the forearm and the fourth and fifth fingers of the hand. The pressure can limit blood flow to and from the arm, causing swelling, redness, and fatigue. Many sufferers of thoracic outlet syndrome have trouble performing overhead activities. Some experience swelling or discoloration of the arm as well as a depression in the shoulder.
Pain can be present on an intermittent or permanent basis. It can be sharp/stabbing, burning, or aching. Pain can also be in the side of the neck, the pectoral area below the clavicle, the armpit/axillary area, and the upper back (i.e., the trapezius and rhomboid area). Discoloration of the hands, one hand colder than the other hand, weakness of the hand and arm muscles, and tingling are commonly present.
Types of TOS
Currently, TOS is classified into three main categories, named according to the cause of the symptoms; however, these classifications are part of the condition’s controversial status because TOS can involve all three types of compression to various degrees.
The compression can occur in three anatomical structures: arteries, veins and nerves; it can be isolated, or, more commonly, two or three of the structures are compressed to greater or lesser degrees. In addition, the compressive forces can be of different magnitude in each affected structure. Therefore, symptoms can be variable.
- Neurogenic thoracic outlet syndrome: This condition is related to abnormalities of bony and soft tissue in the lower neck region (which may include the cervical rib area) that compress and irritate the nerves of the brachial plexus, the complex of nerves that supply motor (movement) and sensory (feeling) function to the arm and hand. Symptoms include weakness or numbness of the hand; decreased size of hand muscles, which usually occurs on one side of the body; and/or pain, tingling, prickling, numbness and weakness of the neck, chest, and arms.
- Venous thoracic outlet syndrome: This condition is caused by damage to the major veins in the lower neck and upper chest. The condition develops suddenly, often after unusual and tiring exercise of the arms. Symptoms include swelling of the hands, fingers and arms, as well as heaviness and weakness of the neck and arms. The veins in the anterior (front) chest wall veins also may appear dilated (swollen).
- Arterial Thoracic Outlet Syndrome: The least common, but most serious, type of TOS is caused by congenital (present at birth) bony abnormalities in the lower neck and upper chest. Symptoms include cold sensitivity in the hands and fingers; numbness, pain or sores of the fingers; and poor blood circulation to the arms, hands and fingers.
Causes of TOS
According to clinical evidence, the disorders caused by TOS are not well understood. When the shoulder muscles are too weak to properly stabilize the collarbone, the bone can slip down and forward into the thoracic outlet. The bone puts pressure on the nerves and blood vessels in this small passageway, creating the various symptoms. Poor posture rapidly aggravates TOS.
The following may increase the risk of developing thoracic outlet syndrome:
- Participating in sports that involve repetitive arm or shoulder movement, such as baseball, swimming, golfing, volleyball and others
- Repetitive motion injuries from carrying heavy shoulder loads
- Trauma to the neck or back (whiplash injury)
- Poor posture
- Anatomical abnormality causing an extra first rib
- Tumors or large lymph nodes in the upper chest or underarm area
- Stress or depression
- Sleep disorders
Often, there is no direct cause found in patients suffering from TOS, which leads to one of the controversial points on the condition.
Chicken or egg?
Since TOS is often the underlying cause of conditions such as frozen shoulder, carpal tunnel syndrome or forward head posture, it is difficult to pinpoint true cause or to determine which came first, TOS or a related condition.
Another clinical puzzle is that the symptoms of TOS mimick other conditions that can produce similar symptoms, such as rotator cuff tear, cervical disc disorders, fibromyalgia, multiple sclerosis and complex regional pain syndrome.
Who is affected by TOS?
Thoracic outlet syndrome can occur in people of all ages and gender, though recent studies have shown that TOS is more common in women, particularly middle-aged women, and those with poor muscular development, poor posture, or both. Clinical evidence suggests that TOS affects less than 2% of the population.
The condition is common among athletes who participate in sports that require repetitive motions of the arm and shoulder, such as baseball (especially pitchers), swimming, volleyball, and weightlifting. It’s not uncommon to see musicians and electricians with TOS, as they work long hours with their hands above their heads.
Several major league baseball players have been diagnosed with TOS. In July this year, Mets starting pitcher Matt Harvey, announced that he is opting to have surgery for TOS after saying “his shoulder was dead, his arm was dead, that there was no energy there and that he couldn’t feel the ball” after his last start.
Musician Isaac Hanson suffered a potentially life-threatening pulmonary embolism as a consequence of thoracic outlet syndrome.
UFC fighter Matt Serra had a rib removed to alleviate TOS, as did singer Tamar Braxton.
NCBI reports that the disagreement regarding the definition of TOS makes the overall incidence of the condition difficult to track. Complicating matters, the recognized prevalence of the diagnosis varies between disciplines. For example, it is estimated that surgeons diagnose TOS 100 times more frequently than neurologists.
In some cases, a thorough evaluation by a neurologist may be recommended to rule out cervical spine disease or other neurological conditions that may be mimicking or causing TOS symptoms.
Additional tests performed to diagnose thoracic outlet syndrome include:
- Nerve conduction studies (to evaluate the function of the motor and sensory nerves)
- Vascular studies (of the arteries or veins)
- Chest X-ray, to rule out cervical rib abnormalities
- Cervical spine X-rays to rule out a cervical rib (extra rib) or cervical (neck) spine abnormalities
- CT scan and (MRI) of the chest
- CT scan or MRI of the spine to rule out cervical spine impingement (pressure), which can mimic neurogenic thoracic outlet syndrome
- Magnetic resonance imaging with angiography (MRA) to view blood vessels
- Arteriogram/venogram (X-ray that uses dye to look at blood flow)
- Blood tests
How to treat TOS
Early identification of TOS can help improve the success of treatment. Thoracic outlet syndrome treatments vary, depending on the type of TOS and symptoms. The goals of treatment are to reduce symptoms and pain.
Treatment of neurogenic thoracic outlet syndrome include:
- Physical therapy / bodywork: The most common initial treatment for neurogenic thoracic outlet syndrome is physical therapy. Physical therapy increases the range of motion of the neck and shoulders, strengthens muscles and promotes better posture. Most patients experience an improvement in symptoms after undergoing physical therapy including deep tissue massage, myofascial release and other bodywork. Of course it makes sense that restoring the posture, flexibility and good biomechanics we’re born with, might be helpful! Watch our how to videos for upper / lower back and chest / shoulders.
- Medications: For pain relief, over-the-counter pain medications, such as aspirin, acetaminophen, or ibuprofen may be recommended. A muscle relaxant or cortisone may be recommended for additional pain relief. Just remember that pharmaceuticals are processed by your liver and may cause unforeseen complications. Please try yoga, physical therapy and bodywork first!
- Surgery: In some cases, surgery may be considered if the symptoms continue if all other efforts fail.
Additionally, stretching, acupuncture, breathing exercises, ergonomic desk set-up, motion and posture practices and chiropractic adjustments, are common non-invasive approaches used in the treatment of TOS.
Ice can be used to decrease inflammation of sore or injured muscles. Heat can also aid in relieving sore muscles by improving blood circulation to them. While the whole arm generally feels painful in TOS, some relief can be seen when ice or heat is intermittently applied to the thoracic region (collar bone, armpit, or shoulder blades).