Thoracic Outlet Syndrome
Joey Laurer, a Division 1 pitcher at Sienna College was having the time of his life. He had just hit 95mph on the radar gun and had been dominant on the mound during the fall of his freshman year. However, after returning from winter break, Laurer couldn’t feel the ball in his hand. He was experiencing numbness throughout his arm, meaning he couldn’t control where the ball was going or how it spun. Like other baseball players, Laurer was experiencing thoracic outlet syndrome (TOS), a condition that causes the compression of nerves and blood vessels in the thoracic outlet. While severe, TOS can be recognized and treated. But to do this, one needs to understand what it is and what it looks like.
Relevant Anatomy:
The thoracic outlet is defined as the space between the clavicle and first rib where the subclavian vein, subclavian artery, and brachial plexus run through. The brachial plexus refers to the nerves that originate near the spinal cord and descend down into the shoulder, arm, and hand to innervate the respective muscles to perform certain actions, such as type this article. This “outlet” is further subdivided into 3 sections: the scalene triangle (Above the clavicle), the costoclavicular space (AKA Cervicoaxillary Canal - Between the clavicle and first rib), and the subcoracoid/pectoralis minor space.
What is TOS?
Normally, everything runs according to plan, with no issues arising in the thoracic outlet. However, when parts of the thoracic outlet become compressed for a variety of reasons (Under causes section), the person is no longer able to function at full capacity due to the variety of symptoms that accompany TOS. But TOS isn’t as clear cut as compression causes the nerves to not transmit signals as well. In fact, there are 3 main types of TOS.
Neurogenic TOS - Neurogenic TOS is by far the most common as it encompasses 90% of all TOS cases. In this situation, the nerves in the brachial plexus are compressed by muscles or other parts forming the “walls” of the thoracic outlet causing numbness or other nerve disorders.
Venous TOS - In this case, one or more of the veins in the thoracic outlet is compressed, thereby increasing the risk for blood clots or blood vessel damage.
Arterial TOS - The rarest case, arterial TOS occurs when one of the arteries is compressed. This can result in damage to the arterial walls which can cause an aneurysm or blood clot formation.
Symptoms of TOS:
As listed above, there are 3 main variations of TOS, each with their own unique symptoms and possible complications. These symptoms can be broken into their respective categories.
Neurogenic:
With neurogenic TOS, all issues are related to compressing nerves such that they are unable to fully transmit their signals resulting in:
Numbness or tingling in the arm or fingers
Pain or aches in the neck, shoulder, arm or hand
Fatigue with activity
Loss of grip strength
Venous: With venous TOS, the compression of the veins prevents proper circulation and can potentially lead to blood clots if the vein is ocluded for too long. Symptoms include:
A change in the color of the hand or one or more fingers.
Hand or arm pain and swelling.
Arterial: Though rare, arterial TOS is extremely dangerous. The occlusion of an artery can have permanent consequences. Similar to venous TOS, its symptoms stem from the compression of a blood vessel. Symptoms include:
Pulsating lump near the clavicle
Cold fingers, hands or arms
Pain in the extremities
Discoloration of the hand or arm
Weak or no pulse
Causes of TOS:
The root cause of all TOS is the compression of the structures in the thoracic outlet. This can be caused by a variety of things including:
Cervical Rib and other Anatomical Differences - In 1-3% of the population, people are born with an extra small rib that originates from the neck above the first rib that compresses the structure. There may also be a tight, fibrous band connecting the rib to the neck that causes the compression of the nerves and blood vessels. Furthermore, abnormalities in the clavicle and scalene muscles may also cause TOS.
Poor Posture - By hunching forward, one can accidentally compress the thoracic outlet, creating this condition. However, this would have to be done for an extensive period of time.
Trauma - Things such as car accidents that cause whiplash may result in internal changes that compress the thoracic outlet. Usually, symptoms from these incidents are delayed.
Hypertrophy - In the case of bodybuilders or other athletes that perform overhead motions, the pectoralis minor, a part of the thoracic outlet, may grow and compress the nerves and blood vessels as it gets larger. Furthermore, an increase in the size of neck muscles may compress the subclavian artery and vein.
Weight Gain and Tumors - Extra tissue such as fat or tumors may compress the strucutres in the thoracic outlet.
Diagnosis:The diagnosis of TOS varies from simple clinical tests to more advanced techniques such as the use of ultrasounds.
Simple In-Clinic Diagnosis:
From the simple end, things such as taking a complete medical history of the patient and utilizing physical tests (Special tests) can be used to help evaluate symptoms. However, it is important to note that these methods have varying levels of accuracy as some generally yield higher false-positive rates. As a result, the most reliable methods fall to imaging and other objective methods.
Imaging and Related Methods:Coupled with the above-mentioned evaluation techniques, some methods that can be used to supplement those findings are the use of diagnostic ultrasound or in venous and arterial TOS cases, catheter-directed venography or arteriography. This allows the clinician to make an accurate assessment of the results and provide the patient with the best possible mode of care.
Treatment for TOS varies depending on whether the injury is neurogenic or vascular.
Neurogenic
In neurogenic cases, physical therapy is often the preliminary treatment to try and alieviate the compression of the nerve. In some cases where PT does not relieve all symptoms, botulinum toxin injections can help alleviate some of the symptoms. However, if all else fails, surgery is always an option. In these cases, the anterior and middle scalene muscles will be surgically cut and the first rib may be removed along with it. In cases where the pectoralis minor is actively compressing the nerve, its associated tendon may be released.
Vascular
Vasucular cases are significantly more complicated than neurogenic cases due to the potential damage to associated blood vessels and the risk of blood clots. In almost all vascular cases, surgery is recommended to decompress the associated blood vessels, recontruct the vessel if needed, and remove any clots before they spread to the rest of the body. A thrombolysis is performed before the TOS surgery to remove any blood clots. In arterial TOS, the artery may be removed and reconstructued if there was an aneurysm.
Conclusion:
Although severe, TOS is not the end of the road for athletes. Many of them can still undergo rehab to return themselves back to their pre-injury-selves. In the case of Joey Laurer, after 2 years of constant work and determination, he has begun to regain his previous command and dominance on the mound. Remember, this article is written for informational purposes. Please consult a medical professional if you think you have TOS.
Sources:
Connolly, Margaret R, and Hugh G Auchincloss. “Anatomy and Embryology of the Thoracic Outlet.” PubMed Central, U.S. National Library of Medicine, 20 Apr. 2021, www.ncbi.nlm.nih.gov/pmc/articles/PMC8057296/#:~:text=The%20thoracic%20outlet%20is%20defined,origins%20to%20their%20peripheral%20termini.
Driveline Baseball. “The Potential Impacts of TOS on a Career and Possible Treatments.” Driveline Baseball, 7 Aug. 2020, www.drivelinebaseball.com/2020/08/the-potential-impacts-of-tos-on-a-career-and-possible-treatments/.
“Thoracic Outlet Syndrome.” Johns Hopkins Medicine, 8 Aug. 2021, www.hopkinsmedicine.org/health/conditions-and-diseases/thoracic-outlet-syndrome.
“Thoracic Outlet Syndrome.” Mayo Clinic, Mayo Foundation for Medical Education and Research, 26 Sept. 2023, www.mayoclinic.org/diseases-conditions/thoracic-outlet-syndrome/symptoms-causes/syc-20353988#:~:text=Thoracic%20outlet%20syndrome%20(TOS)%20is,cause%20numbness%20in%20the%20fingers.
