Thoracic Outlet Syndrome: A Lesser-Known Condition

Back in October of 2022, I wrote a blog post about taking a break from writing. Well, my break is over, and it’s good to be back! Although I haven’t been writing over the past several months, that doesn’t mean I haven’t been learning about writing. Sure, I have a BA, an MA, and a PhD in the subject, but as a lifelong learner, I find there’s always something more I can learn about any topic.

I’ve focused my recent learning on medical writing. Put simply, there are two broad categories of medical writing: writing about complex medical topics for a specialized audience (such as with research articles in medical journals), and writing about complex medical topics for a general audience. During my writing break, I’ve done lots of reading of both kinds of medical writing, and this blog post will be an example of the latter kind.

For a topic, I thought it would be interesting to write about a condition called thoracic outlet syndrome (TOS). Just a few months prior to the start of my writing break, it was announced that prospective Major League Baseball player Cole Henry was diagnosed with this condition and would be having surgery. In this post, I’ll address what TOS is, who gets it, and how it’s treated.

What is TOS?

TOS is a condition in which nerves, an artery, and/or a vein is compressed between the collarbone and the first rib either on one side or on both sides of the body. As Dr. Julie Freischlag, expert in TOS treatment and author of multiple articles about TOS, and her colleague Dr. Kristine Orion explained in the article “Understanding Thoracic Outlet Syndrome,” there are three types of TOS. In neurogenic TOS (nTOS), the nerves passing through the area are compressed. These nerves are called the brachial plexus, and they provide signals to the arm and hand, both of which experience pain with this type of TOS. In venous TOS (vTOS), the vein that passes between the collarbone and the first rib is compressed, hindering the flow of blood from the heart to the arm, often causing blood clots and pain. In arterial TOS (aTOS), the artery passing between the collarbone and first rib is compressed, which not only causes pain but also means blood flow from the arm back to the heart is compromised. The nTOS type of TOS is the most common, affecting 95% of patients with TOS, while aTOS is most rare, affecting only 1-2% of all TOS patients. 

Illustration of the structures involved in thoracic outlet syndrome; missing in the illustration are the neck muscles that attach to the first rib. (Wikimedia Commons/BruceBlaus)

What Causes TOS?

Drs. Freischlag and Orion noted in their article several common causes of TOS. One is some sort of injury to the area, such as from a car crash or a fall. Another is repetitive use of the arms, whether due to work requirements or leisure activities, such as participation in sports or playing an instrument. Still another cause is having a unique anatomy, such as having an extra rib above the first rib that contributes to compression. While the causes of TOS in general have become more well understood in recent years, what is not as well understood is why some people develop nTOS, others vTOS, and still others aTOS. More research in this area is needed.

Who Gets TOS?

Several professional athletes have made the news for their TOS diagnoses. In addition to baseball pitcher Cole Henry, a number of other professional baseball pitchers have been diagnosed with TOS, including Major Leaguers Chris Carpenter, Phil Hughes, and Matt Harvey, to name a few. But baseball pitchers are not the only professional athletes to have been diagnosed with TOS. Notably, NBA player Markelle Fultz of the Philadelphia 76ers received his diagnosis of nTOS in 2018.

In addition to these famous cases of TOS, another famous figure, country music star Eric Church, was also  diagnosed with the condition in 2018. In Church’s case, symptoms of numbness and swelling led to the discovery of a clot and his diagnosis with vTOS. These cases of TOS in those who have achieved fame show that this medical condition can affect anyone with a narrowing of the thoracic outlet, but how widespread is TOS in the general population?

A recently published research study addressed that question. According to the authors, TOS is a rare condition. Based on their research, they estimated that only about 25 out of a million people have nTOS, while only about eight in a million have vTOS. With aTOS accounting for only 1-2% of all TOS patients, we can calculate that fewer than one in a million people have aTOS.

How is TOS Treated?

 

TOS specialist Dr. Freischlag and her colleague Dr. Orion noted in their article that treatment for TOS progresses through several stages. The first step is achieving an accurate diagnosis, and in cases of nTOS, this is best achieved through a physical examination as well as an injection of the numbing agent lidocaine into the scalene muscle in the neck. If this procedure relieves pain, then the doctor can be reasonably sure that TOS is the cause of the problem. In cases of vTOS or aTOS, a blockage of the vein or artery found through ultrasound can eliminate the need for the diagnostic injection.

 

Once an accurate diagnosis is achieved, the doctors explained that patients without a clot generally proceed to treatment with physical therapy and pain relieving medication. In 60-70% of people with TOS, such treatment is sufficient to solve the problem. Those with a vein or artery blockage usually skip this step and proceed directly to surgery.

 

For those whose symptoms are not fully relieved with physical therapy and pain-relieving medication, Drs. Freischlag and Orion described an additional possible step in treatment, injection with Botox. This injection is followed by more physical therapy. If all of these treatments have failed, surgery is the final option.

 

The aim of TOS surgery is to remove the first rib and the scalene muscle in the neck to relieve the compression of the thoracic outlet. There are two approaches to the surgery, one that uses an incision near the collar bone and one that uses an incision in the armpit. A study published in January 2023 in the Journal of Vascular Surgery: Venous and Lymphatic Disorders comparing the two approaches showed both had excellent outcomes.

 

For those interested in more details about how surgeries using the two approaches are conducted, several descriptions are available online. For example, Dr. Freischlag described the armpit approach in a podcast interview, and the podcast also published a video showing Dr. Fresichlag conducting a surgery using this approach. (Warning: Because the video is graphic, viewers must sign in to their Google account in order to verify they are an adult in order to view it.) Also, a video showing the approach near the collar bone has been published by the Journal of Vascular Surgery: Cases, Innovations and Techniques. (Warning: Although the page containing this video features graphic images and the video itself is just as graphic as the one illustrating the armpit approach, there are no viewing restrictions, so readers are encouraged to use caution when opting to view this material.)

 

Possible Failures or Complications of Surgery

 

All surgeries involve risk, and TOS surgery is no exception. Although Drs. Freischlag and Orion noted in their article that 90% of surgeries for TOS are successful, they also concede this means 10% of surgeries are not. They explained that in their experience, these 10% of surgeries occur most often in patients who are over the age of 40, have had symptoms for a long period of time, smoke, or have other pain-causing conditions.

 

Even in successful surgeries, though, complications can occur. One mentioned by Drs. Fresichlag and Orion in their article is a pneumothorax, or collapsed lung, which in their experience occurs in about 10% of cases. Treatment for this complication involves using a chest tube overnight to re-inflate the lung.

 

Other possible complications of TOS surgery are common to any surgery. For example, patients can be allergic to the disinfectant soap used prior to surgery. Anti-itch steroidal cream can treat this complication successfully.

Another possible complication that can occur with the armpit approach is rare and can occur with any thoracic surgery requiring the arm to be pulled overhead. This complication, an injury to the axillary nerve, results in a painful condition called quadrilateral space syndrome. Luckily, as reported in the Annals of Thoracic Surgery, for about 75% of patients with the condition, physical therapy is the only needed treatment.

Certainly this is not an exhaustive list of possible complications. Before having any surgery, patients should review the risks and benefits with their surgeon. With a 90% success rate and most complications occurring 10% of the time or less, TOS surgery seems to be relatively safe and worth the risks for patients who have not found relief through non-surgical treatments. Odds for a successful surgery can be increased by choosing a top surgeon for treatment, many of whom wrote the textbook on the condition, now in its second edition.