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A glimpse - Thoracic outlet syndrome 😵💫
Justas Muzikevicius
October 25, 2024
Sports Med U | Educating Minds, Elevating Potential
Thoracic outlet syndrome: a narrative review
Masocatto, N.O., Da-Matta, T., Prozzo, T.G., Couto, W.J. and Porfirio, G., 2019. Thoracic outlet syndrome: a narrative review. Revista do Colégio Brasileiro de Cirurgiões, 46, p.e20192243.
In today’s letter
Overview of the thoracic outlet syndrome
Rapid Results = There are 3 types of Thoracic outlet syndome:
Neurogenic (nerve-related) = Symptoms include: weakness, numbness, tingling (paresthesia), and pain in the arm
Venous (vein-related = Symptoms include: swelling (edema) and severe pain
Arterial (artery-related) = Symptoms include: non-radiating pain, coldness in the arm, and paleness due to poor circulation.
3 recources to check out to further you knowledge about thoracic outlet syndrome
Meme of the week: Was it easy, moderate or hard ? 😄
Bite-size study - A glimpse into our Infographic
Full infographic and clinical tips 👇
Deeper look
Aim of the study
The goal of this study is to provide a detailed review of thoracic outlet syndrome, looking into its:
Causes (etiology)
How it develops (pathophysiology)
How often it occurs (epidemiology)
How it’s diagnosed and treated
What other conditions it could be confused with (differential diagnoses)
Did you know?
In 1956, Peet and colleagues were the first to name "Thoracic Outlet Syndrome" (TOS) to describe a set of symptoms caused by pressure on nerves and blood vessels in the thoracic outlet, a small space between the collarbone and first rib.
The structures that typically cause this compression are the first rib and a muscle called the anterior scalene. These mainly affect the brachial plexus (nerves to the arm) and subclavian vessels (major blood vessels).
There are 3 main types of TOS, each affecting different parts of the body:
Neurogenic (nerve-related)
Venous (vein-related
Arterial (artery-related).
It's possible for a patient to experience more than 1 type of TOS at the same time, though this is less common.
Neurogenic TOS is the most common. Its symptoms include weakness, numbness, tingling (paresthesia), and pain in the arm.
The venous form usually causes swelling (edema) and severe pain, particularly in the affected arm.
Arterial, on the other hand, leads to non-radiating pain (not spreading from one area), coldness in the arm, and paleness (pallor) due to poor circulation.
Thoracic outlet syndrome is quite rare, but it can be serious, especially in younger adults, typically those aged between 20 and 40.
Study Review
The authors looked for scientific articles in the PubMed database using the term “thoracic outlet syndrome.”
They focused on studies published between 2012 and 2017, including reviews, systematic reviews, meta-analyses, clinical trials, and observational studies.
Out of 47 articles, they chose 8 for this narrative review
Cause & How It Develops
Thoracic Outlet Syndrome happens when the subclavian-axillary vessels or the brachial plexus (nerves and blood vessels to the arm) get compressed in the thoracic outlet.
Compression usually happens in 3 areas:
The intercostal-scalene triangle
The costoclavicular space (between the collarbone and first rib)
The retro-coraco-pectoral space (behind the pectoral muscles).
There are 2 main causes of TOS: soft tissue issues (like muscle or ligament problems) and bone abnormalities.
Around 70% of TOS cases are related to soft tissue, while the other 30% are due to bone issues.
The most common trigger is trauma—an injury can deform the ribs or the cervical plexus, leading to compression of the nerves or blood vessels.
It can also develop from repetitive movements over time, like certain exercises, weight training, or even repetitive tasks at work, such as stocking shelves.
How Often It Occurs
Interpreting data on Thoracic Outlet Syndrome can be tricky because cases are often underreported due to inconsistent diagnostic criteria.
The estimated incidence of TOS can vary widely, ranging from 3 to 80 cases per 1,000 people.
The neurogenic form is by far the most common, making up over 90% of cases.
The venous form appears in around 3% to 5% of cases, while the arterial form is the rarest, showing up in less than 1% of patients.
Vascular forms typically develop between the ages of 20 and 30, while the neurogenic form usually affects people between 20 and 40
Diagnosis
The symptoms of TOS largely depend on the specific type of TOS and the underlying pathophysiological mechanism involved.
Arterial Form
According to Daniels et al., patients with the arterial form of TOS often experience persistent, non-radiating pain, numbness, and discomfort in the affected limb.
Symptoms tend to worsen during physical activity and improve with rest.
There are no specific signs or symptoms unique to the arterial form, making diagnosis tricky.
On physical examination, common signs include coldness and paleness in the affected side.
Paleness is usually more noticeable in the upper limb, and skin changes can occur, particularly in the distal parts.
Venous Form
Grunebach et al. note that the first symptom of venous form is usually swelling (edema) in the upper limb.
Severe pain may occur a few days before the swelling develops.
During a physical exam, the affected arm may have a bluish color (cyanosis).
Dilated superficial veins may be visible in the upper arm, neck, and chest.
Neurological Form
Franklin et al. describe the classic symptoms of neurogenic TOS as pain, tingling (paresthesia) in the fingers, and weakness in the arm.
Physical examination often shows tenderness when palpating above the brachial plexus, trapezius, and scalene muscles, or in the anterior chest wall, but these are not unique to TOS.
Symptoms are generally aggravated by activities like reaching overhead or extending the arm, such as picking up items from a high shelf.
A systematic review found that 76% of patients with neurogenic form experienced occipital headaches.
Physical Tests
Several maneuvers are used to help diagnose TOS, but NONE are considered definitive.
Adson’s manoeuvre involves palpating the radial pulse, extending the elbow, raising the arm, and rotating the head toward the affected side while the patient inhales deeply.
This test may reproduce tingling or numbness (paresthesia) along the brachial plexus and could lead to the disappearance of the radial pulse on the affected side.
However, Adson’s maneuver is not a reliable standalone test for TOS, as up to 40% of healthy people can also experience pulse disappearance by moving their arm.
It’s especially unreliable for diagnosing the venous form of TOS.
Elvey’s maneuver tests for nerve compression by extending the arm and rotating the head in the opposite direction. This maneuver may trigger tingling and pain.
Currently, there’s no universal agreement on the diagnostic accuracy of these clinical maneuvers.
Imaging
Imaging tests are often recommended for patients with TOS symptoms and include MRI, CT scans, electromyoneurography (EMNG), nerve conduction studies (NCS), and ultrasonography (USG).
These imaging techniques are particularly useful in diagnosing the vascular forms of TOS.
However, in patients with the neurogenic form, imaging results may appear normal, making it harder to confirm the diagnosis.
Other Conditions That Might Mimic it
The symptoms of Thoracic Outlet Syndrome can vary a lot, from mild discomfort to more severe issues.
Patients can have symptoms on one side (unilateral) or both sides (bilateral), with a mix of nerve and blood vessel compression signs.
According to Kuhn et al., cervical spine (neck) issues often cause constant pain in the neck and shoulder, which can worsen depending on the neck’s position.
This neck pain may sometimes radiate down the arms, and certain shoulder positions or pressing on joint areas can make the symptoms worse.
Treatment
The main goals of treating Thoracic Outlet Syndrome are to relieve symptoms and prevent complications.
Kuhn & colleugues outlined that treatment should start with non-surgical methods, and surgery is only considered if those methods fail.
The type of TOS (neurogenic, venous, or arterial) and the structures involved will guide the treatment approach. Initial treatments usually focus on symptom relief with light soft tissue release, anti-inflammatory medication, and lifestyle adjustments.
For neurogenic form, physio, postural corrections, and anti-inflammatory medications are typically the first line of treatment. Many patients can achieve symptom relief without needing surgery.
Venous TOS treatment has traditionally focused on managing symptoms with anticoagulants. However, this approach can lead to issues like ongoing pain, repeated blood clots, and reduced arm mobility, making daily activities harder.
Thrombolysis, which involves using a plasminogen activator to break up clots, is the preferred and most effective treatment for venous form, especially if started within two weeks of symptom onset. This has a nearly 100% success rate in restoring proper blood flow through the subclavian vein.
The treatment for arterial TOS depends on the affected structure. Surgery is often the most effective option, though it comes with some risk of complications. For mild cases of arterial blockages, catheter-directed thrombolysis (breaking up clots before surgery) may be a good option.
Surgery is only required in a small number of cases, usually when there are bone abnormalities, vascular complications, trauma, sensory loss, or worsening pain that can lead to numbness in the arm, or when non-surgical treatments fail.
Surgical procedures for TOS involve decompressing the nerves or blood vessels, and the approach depends on the affected area. Techniques include transaxillary, supraclavicular, infraclavicular, and thoracoplasty (anterior or posterior), with the choice depending on the surgeon's preference and the specific anatomical region involved
Top 3 resources
To learn more about thoracic outlet syndrome
Credit @Physiofunnies
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