The text below is the transcript of the video by Dr. Kamran Aghayev. If you wish to explore the Thoracic Outlet Syndrome topic in more detail, consider reading the following articles: What is Thoracic Outlet Syndrome? | Thoracic Outlet Syndrome Diagnosis | Thoracic Outlet Syndrome Signs and Symptoms | Standard Thoracic Outlet Syndrome Surgery | Persistent and Recurrent Thoracic Outlet Syndrome | PURED Procedure for Thoracic Outlet Syndrome
Thoracic Outlet Syndrome is probably one of the most controversial topics in medicine. If you are watching this video, you might think that you have TOS, and if so, you’ve come to the right place because today I will explain to you everything you need to know about this enigmatic disease. My name is Kamran Aghayev. I am a neurosurgeon, and welcome to Neurosurgery Explained.
First, I must tell you that this video is not medical advice. It is purely for educational purposes and aims to give you comprehensive information about Thoracic Outlet Syndrome.
What is Thoracic Outlet Syndrome?
Let’s start with the definition. What is Thoracic Outlet Syndrome? Thoracic Outlet Syndrome, or simply TOS, is a general term describing several conditions associated with the compression of nerves and vessels in the thoracic outlet area.
Well, what does this definition mean? It means that if you have TOS, some nerves and blood vessels in the thoracic outlet area are physically compressed. But this definition raises two very important questions.
The Thoracic Outlet Area
First, what is the thoracic outlet area? Or specifically, where is the thoracic outlet area? It is an area located at the top of the chest cavity, kind of representing an exit. If you imagine the chest cavity as a chimney, the thoracic outlet area is like a ventilation window. Strictly speaking, it’s not a good definition because there is nothing physically coming out of this outlet. It’s just the upper boundary of the chest cavity.
Believe it or not, in older publications, this area was sometimes called the thoracic inlet area. Anyway, this area has a heart-shaped contour bounded by the first thoracic vertebra, the left and right first ribs, and the upper edge of the sternum.
The Nerves and Vessels Compression in the Thoracic Outlet Area
The second question, what are the nerves and vessels compressed in this area? The answer is the brachial plexus, subclavian artery, and subclavian vein.
That may be a little bit too technical, so let’s elaborate. The brachial plexus is a network of nerves connecting the spinal cord with the arm. This plexus carries impulses between the spinal cord and the arm. The nerves are basically communication lines, and impulses are bits of information flowing to and from the arm. These impulses are electrical signals, and they control skin sensation, muscle contraction, sweating, blood vessel tone—everything, you name it.
If nerves are compromised, then the flow of signals is disrupted, which leads to the disease. The subclavian artery and vein are two vessels providing blood flow to the arm and from the arm back to the heart. They are essentially pipelines with blood flowing inside of them. When they are compressed from outside, they become narrow and blood flow gets obstructed.
Types of Thoracic Outlet Syndrome
Depending on what structure is affected, TOS has three clinical variants.
The neurogenic form, or nTOS, is the most common form, accounting for approximately 80% to 85% of all TOS cases. The brachial plexus is compressed, which means that symptoms develop due to the disruption of neural impulses. These symptoms include pain, numbness, a tingling sensation, pins and needles, and muscle weakness. The skin of the fourth and fifth fingers is typically affected.
Venous TOS, or vTOS, is a less common variant, comprising about 15% to 20% of cases. The subclavian vein is compressed and symptoms develop due to insufficient blood return from the arm. You may think that having more blood in your arm might be a good thing; unfortunately, that is not the case.
You see, venous blood contains waste products and very little oxygen, which negatively affects the arm. Venous congestion is like a traffic jam. Symptoms of venous TOS include cyanosis, which is a dark blue discoloration, swelling or edema, visibly large veins, and pain.
Arterial TOS, or aTOS, is the least common form, with approximately 1% to 2% of all TOS cases. The subclavian artery is compressed, which leads to insufficient blood flow to the affected arm. This causes symptoms like paleness, coldness, and pain in the arm and hand. The fingertips are particularly affected and, in very severe cases, ischemia may develop.
Thoracic Outlet Syndrome Signs and Symptoms
Typically, TOS patients experience problems when keeping their arms above their head. Activities such as hair care, holding a phone, and other overhead tasks become painful, numbing, and difficult.
TOS is a collective term describing the site of the disease rather than the cause. It is like other entrapment neuropathies, such as carpal tunnel syndrome or cubital tunnel syndrome, which basically say nothing about the cause of the condition. To make things worse, there is no single factor causing Thoracic Outlet Syndrome. Multiple causes have been identified.
For example, women are affected three to four times more often than men. People who extensively use their arms and hands for work also tend to develop TOS. Scientific evidence shows that the cause is skeletal and muscular abnormalities. These abnormalities are frequently very subtle, making them very hard to diagnose.
Causes and underlying conditions for TOS
Now, we will discuss the most common underlying conditions for Thoracic Outlet Syndrome.
Cervical Accessory Rib
A cervical accessory rib is usually part of the abnormality. Normally, there are twelve pairs of ribs in the human body, totaling 24. They form the chest cavity and provide protection for the heart and lungs and are essential for normal breathing. Some people have additional or accessory cervical ribs. A recent large-scale meta-analysis found that 1.1% of the general population has cervical ribs. The incidence of cervical ribs in TOS patients is 29%, which means that if you have a cervical rib, then you are 25 times more likely to develop TOS than the general population.
These ribs extend from the 7th cervical vertebra, above the first rib. The shape and size of accessory ribs may vary from a slightly elongated transverse process to a well-formed, almost normal-looking rib. These extra ribs either directly compress the nerves and vessels or distort the paths leading to Thoracic Outlet Syndrome. Accessory ribs are very easy to diagnose on X-rays if you’re familiar with them. Unfortunately, in most cases, that is not the case because most physicians are inexperienced with accessory ribs, and they are frequently missed.
First Rib Abnormalities
The first rib is a C-shaped flat bone. It forms the most part of the thoracic outlet area and is the main culprit for TOS. The problem may come from the shape or the position of the first rib. For example, one study found that widening of the first rib is strongly associated with Thoracic Outlet Syndrome. Another study has found that abnormal bone prominence is responsible for venous congestion.
Unlike cervical ribs, these abnormalities are less evident on X-rays and are hard to diagnose. Only well-experienced specialists may notice them, and sometimes a CT scan with additional three-dimensional remodeling is necessary to identify these problems.
Fibromuscular Soft Tissue Bands
Fibromuscular soft tissue bands constitute a significant portion of TOS cases. The cause of compression may be an abnormal muscle, a fibrous band, or a combination of them. Scalenus anticus, Scalenus minimus, and subclavius posticus are examples of such muscles.
Although their incidence is relatively rare, these structures are basically bands or strings. They are present in the thoracic outlet area and compress the neurovascular bundle.
Hypertrophic Muscles
Hypertrophic muscles may also cause compression in the thoracic outlet area. In case you don’t know, hypertrophic means enlarged. People who extensively use their arms and hands for work and sports can develop Thoracic Outlet Syndrome. For example, professional athletes, musicians, hairdressers are prone to developing TOS.
Scalene muscle hypertrophy usually leads to neurogenic and arterial TOS since both the artery and brachial plexus run inside the scalene triangle. Subclavius muscle hypertrophy, on the other hand, causes compression and sometimes even thrombosis of the subclavian vein. This clinical variant is called Paget-Schroetter disease.
The Nutcracker Mechanism And Post-Clavicular Compression
Both the clavicle and the first rib make a joint with the upper part of the sternum. The first rib is fixed, but the clavicle is quite mobile. The clavicle is attached to the sternum and connects the arm with the rest of the body. It is basically a lever. When the arm moves up, the clavicle changes its position and the distance between the clavicle and first rib gets smaller. This gap between the clavicle and the first rib is called the costoclavicular space, and usually, it is quite wide. Nerves and vessels freely pass through this space.
When the arm is raised, this space may become very narrow. It is called the nutcracker mechanism. Studies show that in a normal person, the costoclavicular distance does not change very much with arm movements, while in TOS patients, it dramatically decreases.
Diagnosing TOS: MRI and Provocative Imaging
The nutcracker mechanism is the leading cause of Thoracic Outlet Syndrome, but it is not easy to diagnose. The best choice is to use MRI because it allows direct measurement of the distance between the clavicle and the first rib, but MRI scans should be performed with arms in both up and down positions.
This is called provocative imaging, because we provoke narrowing to show on MRI. Only by showing significant narrowing of the space with provocative testing can we confirm the diagnosis. Unfortunately, this technique is not widely used.
Neurovascular Conflict
Another less known mechanism for TOS comes from subclavian artery or vein branches. These branches loop around the brachial plexus and may directly compress or tether the nerves. These vascular causes have been identified as a source of TOS relatively recently, and research in this area is still ongoing.
Chronic Kidney Disease And Dialysis in Relation to TOS
What does chronic kidney disease and dialysis have to do with TOS? Well, nothing directly. It is not the disease, but the way we treat it that causes TOS. Therapeutic arteriovenous fistula is a very common method used for easy vascular access in hemodialysis patients. However, one of the major shortcomings is increased blood flow and turbulence in the subclavian vein. This leads to central venous stenosis and Thoracic Outlet Syndrome. Like in most venous Thoracic Outlet Syndrome cases.
This stenosis usually develops in the costoclavicular space where the nutcracker effect between the clavicle and first rib exists.
Thoracic Outlet Syndrome Treatment Overview
What is the treatment for Thoracic Outlet Syndrome? It is usually said that light or moderate cases should be managed conservatively. Arm rest, physical therapy, painkillers, breathing exercises, stretching, and postural exercises may be helpful, but physical therapy usually does not provide permanent relief, especially if there is an underlying musculoskeletal anatomical abnormality.
In case you missed the previous section, that’s almost all TOS cases. There are not too many studies regarding the efficacy of physical therapy in TOS. The only one prospective randomized study found that surgery provides better results in comparison with conservative treatment.
TOS Surgery: Why are the Majority of Surgeons Doing It Wrong?
Since the cause of TOS is anatomical, at least in the majority of cases, surgery is the only way to permanently treat the disease. Surgery aims to decompress the thoracic outlet area and therefore is called thoracic outlet decompression or TOD.
To achieve decompression, the surgeon must remove the first rib, find the nerves, artery, and vein, and free them up by cutting all muscular and fibrotic bands. This is how the surgery should be done, in theory at least. But in practice, we are far from ideal. To simplify the procedure, some surgeons do not remove the first rib and perform only soft tissue release.
It’s hard to believe that this is how things are in the 21st century, but this is done every day and some surgeons actually defend this method. They regularly publish scientific papers about this technique and, according to them, it is a good option for TOS treatment. This procedure is called neurolysis or neuroplasty. Its efficacy has been studied only in one prospective randomized trial. By the way, prospective randomized trials provide the best evidence in medicine. They are not ideal, but they are the best of what we have.
The Importance Of The Extent Of Rib Removal
Back to the topic, the study compared first rib resection with no resection and found that removal provides significantly better results. The surgeons concluded that the major compressive element in patients with TOS-associated pain appeared to be the first rib. Now we know that first rib removal is an essential part of thoracic outlet decompression.
But this is an area where there’s a lot of confusion, and I’m not talking about the public—even many doctors don’t have enough information about this matter. Basically, not all rib resections are equal. There is overwhelming scientific evidence indicating that the extent of first rib removal influences success. It basically means more bone removal gives better results. Partial or incomplete removal leaves bone stumps which cause recurrence.
One study from Italy found that the lengths of the remaining rib stumps affect the success of the surgery. Similar results came later in 2014 from Johns Hopkins University. Essentially, all high-quality studies indicate that to achieve good results, the first rib should be completely removed. Keep this information in mind because we will return to this matter again when we discuss surgical methods.
We will discuss surgical techniques in detail because they are super important. This information is absolutely crucial, so pay attention, especially if you are considering surgery for your TOS treatment.
Anterior Supraclavicular Approach
The anterior supraclavicular approach allows the surgeon to access the brachial plexus and subclavian vessels from the front, which is what “anterior” means, and above the clavicle, which is what “supraclavicular” means. So, it means that the approach is from the front and above the collarbone.
The major handicap of this approach is limited access for the complete removal of the first rib. It is technically very difficult because the first rib is located deep under the brachial plexus and subclavian artery and vein. To reach and remove the first rib, nerves and vessels must be moved aside. However, nerves and vessels do not tolerate manipulation well. They may get hurt, and several complications may develop during or after the surgery.
A recent large literature review from Japan analyzed the outcomes and complications of each surgical technique. This report found that the complete relief rate is only 57%, and the risk of neurological injury is 3%. Also, there is a small but significant risk of vascular injury and death.
As I mentioned, it is very difficult, almost impossible, to completely remove the first rib from an anterior approach. Therefore, usually, bone leftovers remain after surgery. These stumps cause recurrence of symptoms.
Patients sometimes do not benefit from surgery at all or develop a recurrence after some period of improvement. Some patients may become worse than before because of nerve manipulation during surgery.
Lateral (Transaxillary) Approach
The lateral or transaxillary approach allows the surgeon to approach the first rib from the side, under the armpit—that’s what “lateral transaxillary” means. This approach is used by thoracic surgeons.
The window is usually narrow and very deep, and only the mid-portion of the first rib can be reached. Therefore, vascular TOS cases, primarily arterial TOS, can be effectively treated. The posterior portion, the back portion of the first rib, is very hard, not impossible though, to expose and remove with this approach. Literature review found a 53% complete relief rate and a 5% risk of neurological injury. Again, there is a small but real risk of vascular injury and death.
The results of this approach are quite similar to the anterior supraclavicular approach. The main problem with this approach is the inability to remove the first rib completely. Another major handicap of the transaxillary approach is limited access to the brachial plexus itself. Even if the entire first rib resection is performed, only a very limited portion of the brachial plexus can be visualized and decompressed.
You can’t really go high with this approach because your starting point is very low, so soft tissue bundles usually remain after surgery, and this is another reason for recurrence.
Anterior Infraclavicular Approach
This approach is used exclusively for venous TOS; the surgeon approaches the first rib from an incision below the collarbone, which is what “infraclavicular” means. Only the front portion of the first rib can be reached and removed. Therefore, only the subclavian vein can be decompressed. It is a good surgical choice but only for isolated venous TOS cases like McCleary syndrome or Paget-Schroetter syndrome.
However, it’s not universal. Neurogenic and arterial TOS are not suitable for an anterior infraclavicular approach, and you may remember that the neurogenic form is the most frequent clinical variant.
Endoscopic and Robotic Approaches
These approaches are relatively new and have evolved over the last 20 or so years. Endoscopic surgical tools or robotic systems are placed inside the chest cavity, and the first rib is approached from below. The main problem with this technique is again the incomplete resection of the first rib, leading to recurrence.
Clinical outcomes for endoscopic and robotic TOS surgery are very similar to traditional supraclavicular and transaxillary approaches.
PURED Technique For Thoracic Outlet Syndrome
As you can see, all surgical techniques used for TOS suffer from the same setback, which is the inability to remove the first rib completely. Therefore, I invented the PURED technique in 2015 and have been implementing it since then. PURED is an acronym that stands for Posterior Upper Rib Excision and Decompression.
The surgery is performed from the back. First, the transverse processes of C7 and T1 are removed. Then, the first rib is divided into two parts. This division increases the mobility of the remaining pieces and makes it easier for the surgeon to remove the rest.
First, the smaller part is removed piece by piece. Then, the muscles are detached from the larger part, which is gradually removed in small bites. During this process, the nerves and the artery are not disturbed. Only the subclavian vein is slightly moved to expose and remove the very last bit of the first rib. Once the rib is completely resected, scalenectomy is performed, and the nerves and vessels are completely decompressed.
The surgical working line is in a plane with the first rib, and exposure and removal of the first rib is very easy and straightforward. The entire first rib can be removed with this approach with zero leftovers. During rib removal, there is no nerve manipulation.
What’s The Best Treatment for TOS?
There are two main advantages of the PURED approach: efficacy and safety. There are no rib leftovers, and neurolysis and neuroplasty can be performed widely, which makes this approach the most effective treatment of TOS ever employed.
There is simply no other surgical technique that can allow such unprecedented exposure. The second advantage is safety. There is not much manipulation of the nerves and vessels during the surgery. Therefore, the procedure has a very low complication rate. I have performed more than 100 surgeries over the last ten years and have not seen any significant complications like neurological or vascular injuries which may have a permanent effect on patients, and therefore none of my patients have developed a recurrence.
This concludes our discussion today regarding Thoracic Outlet Syndrome. Thank you very much and see you next time.
