Thoracic Outlet Syndrome

An Overview of Thoracic Outlet Syndrome

Thoracic outlet syndrome is an uncomfortable condition characterized by numbness and pain radiating down the arm associated with shoulder position. Severe cases can also block the flow of the main artery that supplies the arm (very rare).

Women tend to have more incidence of thoracic outlet syndrome than men do. Individuals that become more involved in overhead activity (swimmers, stocking clerks, carpenters) tend to have a higher incidence of this disorder as well as weight lifters. Injuries to the clavicle (collar bone) can also produce thoracic outlet syndrome.

Thoracic outlet syndrome develops due to abnormal pressure on the nerves called the brachial plexus that travel through the tunnels of the shoulder. The “thoracic outlet” consists of multiple tunnels that these nerves (and blood vessels) travel through.

Anatomy of the Thoracic Outlet

The origin of the nerves in the shoulder stem from the spinal nerves. These spinal nerves exit through the holes in the bones of the neck vertebra (foramen). The spinal nerves can become individually compressed in these bony holes. This condition is called foraminal stenosis or radiculopathy and can occur from a bone spur or compression from a herniated disc. This type of compression can be mistaken for thoracic outlet syndrome and is discussed in another section on this website under cervical radiculopathy and cervical herniated disc.

The nerves that travel down into the arm (brachial plexus) originate from the spinal nerves C5 through T1. The C5 nerve exits between the C4 and C5 vertebrae, the C6 nerve exits between the C5 and C6 vertebrae and so on until the T1 nerve where this nerve exits between the T1 and T2 vertebrae. Even though there are only seven cervical vertebrae, there is a C8 nerve, which exits between C7 and T1. When these nerves finally exit from the spinal canal, they travel through different structures to get to their respective targets. The targets of these nerves are muscle, joint, tendon, bone and skin.

When these individual nerves exit from the spinal foramen, they join together, separate and then join again in a peculiar “dance” called the brachial plexus. This nerve plexus has three tunnels that it passes through. The first tunnel is the path between the scalene muscles. The second tunnel is the area between the clavicle (collar bone) and the first rib. The last tunnel is located between the pectoralis minor muscle tendon and the acromion (part of the bony shoulder blade that protrudes in front to provide a lever arm for this muscle).

The first tunnel is located in between two muscles; the scalenus anticus and scalenus medius. These muscles originate from the first rib and insert on the transverse processes of the side of the cervical vertebra. It just so happens that the spinal nerves exit the foramen in the spine right between these two muscles. A very tight band of muscle or a more rigid tendon or fibrous band within the muscle can impinge upon these nerves causing symptoms.

The brachial artery joins these nerves low in this interval. As an interesting point of anatomy, the brachial vein is not present in this first tunnel. The brachial artery comes in very handy in the case of testing for thoracic outlet syndrome, which will be covered later in this topic.

The second tunnel is located between the first rib and the clavicle (collar bone). There are three structures that descend into the arm through this tunnel; the aforementioned brachial plexus, the brachial artery and the brachial vein. Compression can occur to the nerves if there is abnormal motion of the clavicle, as the clavicle is designed to move and rotate when the shoulder moves. The clavicle acts like a strut when the shoulder is overhead and can impinge upon these nerves. Thickening of the clavicle (in the case of a healed fracture) can also impinge the brachial plexus).

The last tunnel the brachial plexus has to negotiate through before this nerve plexus finally splits up into the respective peripheral nerves is the tunnel between the tendon of the pectoralis minor and the acromion of the shoulder blade. The nerves the brachial plexus finally separates into are the musculocutaneous, axillary, median, ulnar and radial nerves.

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(Please keep reading below for more information on this condition.)

Pathology (what can go wrong)

Any narrowing of these tunnels can compress the nerves with certain shoulder positions and produce symptoms. Shoulder movements that normally cause symptoms involve bringing the arm overhead, reaching at shoulder height or behind the body. Symptoms are characterized as numbness, pain, paresthesias (pins and needles) and a feeling of “deadness” in the arm that radiates into the hand. The outside of the hand (opposite the thumb side) is typically affected.

Neck motion can also cause impingement if the nerves are caught in the first tunnel (scalenus anticus and medius). Typically, with this entrapment, turning the head to the symptomatic side can bring on the symptoms. If the symptoms are brought about by looking up (cervical extension) without lifting the shoulder, the disorder more likely than not is from compression of the nerves in the neck (radiculopathy) and not in the shoulder (thoracic outlet syndrome).

Cervical ribs are extra ribs that have formed congenitally (in the womb) and occur in less than one percent of the population. These ribs are typically identified on an X-ray. If cervical ribs are present, these ribs can crowd out the nerves and artery in the first or second tunnels. The presence of these extra ribs does not mean that one will have thoracic outlet syndrome as less than ten percent of patients with these ribs have thoracic outlet symptoms.

It is very rare that motor strength is diminished by thoracic outlet syndrome as the sufferer will stop whatever activity is causing the symptoms and the compression injury to the nerves is short lived. In very severe cases however, muscle weakness can occur.

The symptoms can become so severe that simply holding the arms on a steering wheel can produce pain and numbness. Some patients complain that the arm “goes dead” in this position. Sleeping can be a challenge to some as inadvertently, these individuals sleep with their arm overhead or the shoulder “scrunched up” under the pillow, which then compresses the brachial plexus. These nerve symptoms can cause the patient to awaken in the middle of the night.

The symptoms that occur when the brachial plexus nerves are compressed are very similar to the “funny bone” (ulnar) nerve at the elbow becoming compressed. Everyone has had the experience that resting the inside of their elbow on a hard surface for a long period of time will cause the typical numbness and pins and needles to radiate into the outside of the hand as the hand “falls asleep”. These symptoms occur due to pressure on the ulnar nerve at the elbow. Pressure prevents nerve conduction.

An interesting fact is that this same ulnar nerve (which originates in the shoulder) is also the typical nerve that is most affected with compression in the thoracic outlet. This is due to the fact that the ulnar nerve originates from the lower roots of the brachial plexus. These lower roots are stretched a longer distance with overhead activity (like a cable that runs over a pulley). This is similar to a track star that runs the race on the outside of the track. He or she has to run a longer distance than the runner on the inside of the track if this individual stays in the outside lane.

Diagnosis of Thoracic Outlet Syndrome

Diagnosis is made with a thorough history, physical examination and the use of imaging studies. Differential diagnosis has to consider compression of the nerves in the neck (radiculopathy) as a cause of symptoms.

There are physical examination tests that can indicate the presence of thoracic outlet syndrome. The three main tests are called the “Roos”, “Wright’s” and “Adson’s” tests. Two of the tests “(Wright’s” and “Adson’s”) depend upon loss of the pulse of the brachial artery. This loss of pulse is unfortunately not a great indicator of presence of thoracic outlet syndrome but is helpful in the general diagnosis.

X-rays of the neck and shoulder are taken to make sure there are no cervical ribs and no old healed fractures of the clavicle that could produce a bony compression in the tunnel. An MRI of the neck is performed if there is any evidence of spinal nerve involvement. Occasionally, an MRI of the shoulder is ordered to make sure there are no very rare nerve root tumors or a Pancoast tumor (a tumor at the top of the lung that can also cause this syndrome).

Nerve conduction tests (EMGs and NCVs) are not generally useful in the diagnosis of this disorder as motor strength is very rarely diminished (which will produce negative EMGs) and the nerve bundle cannot be tested for conduction speed across the brachial plexus (the NCV test).

Treatment of Thoracic Outlet Syndrome

Treatment is a physical therapy program or chiropractic treatment that stretches the muscles, mobilizes the clavicle and eliminates the faults in motion of the shoulder. Occasionally, steroid injections can be helpful. Surgery is only called for in severe cases.

For more resources on thoracic outlet syndrome, or to determine your treatment options, please contact the practice of Dr. Donald Corenman, neck doctor and spine specialist offering diagnostic and surgical second opinions to patients in the USA and around the world.

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Eric S

Sep 26, 2021

by Eric S on Donald Corenman, MD, DC

Successful pars repair at 46 years old

Back in November of 2018 (at 46 years old) I came from Vancouver BC to have a pars repair done with Dr. Donald Corenman at the Steadman Clinic in Vail Colorado. I'm finally posting this review nearly three years later in late 2021. The reason I waited so long was I wanted to know the final result before I posted my review. Unfortunately in that time Dr. Corenman has retired. Nevertheless, I want to post this review of Dr. Corenman and his staff at the Steadman Clinic in their excellent treatment of my L5 pars interarticularis.

I fractured my pars at age 42 back in 2014 when rolling on the gym floor, and was denied treatment by the Canadian healthcare system, probably due to my age. First my GP told me there was no surgical option for a pars defect, which was quite incorrect! I tried to live with it, but the symptoms worsened (periodic random spine slippage and weeks of resultant pain after just bending over to tie my shoe, so I eventually learned to mostly squat and hardly bend). When I finally consulted with Canadian spine surgeons, I was told they believed my pars defect had been congenital (since birth). This was absurd, considering I had done extreme martial arts (including jiu jitsu) for years prior, as well as 5 years of reinforcing steel full time in my 20s, probably the hardest job on the back you can find. No pars defect like mine would possibly have allowed this--ergo it was impossible that I had had the defect since birth. I did however have an asymptomatic congenital spina bifida occulta that made me more susceptible to a pars fracture. In 2014 in one instant, I went from having the strongest back people I knew said they'd ever seen, to being unable to safely bend over and tie my shoe without a non-negligible risk of my spine slipping randomly (which would lead to weeks of pain after each occurrence). This was due to the unilateral L5 pars defect, otherwise known as spondylolysis. It was when lying in pain on the floor 4 years later after maybe the 6th spine slippage event post injury, that I had had enough, and resolved to have surgery. If Canada's "universal health care" said no, I would make lemonade from lemons, and find the very best surgeon in the world at pars repairs. That was Dr. Donald Corenman. Dr. Corenman back in 2018 ran a website https://neckandback.com/ that dedicated many pages to the science of every aspect of pars repairs, from eligibility (good discs on MRI), to best surgical techniques (minimal open compared to minimally invasive), best imaging to use (i.e., O-Arm with Stealth imaging vs. older fluoroscopy), the ideal amount of BMP to use and why not use too much or too little, and much more, all to do with pars repairs, pages upon pages of his site just on the pars, with scientific references and his own extensive expert opinion. As a health research statistician, I was very impressed with this. It was in stark contrast to the websites of other spine surgeons which barely gave the pars a word or two, focusing almost exclusively on fusions. I had found the best surgeon in the world for pars repairs, and so after Dr. Corenman personally screened my MRI to ensure my discs were healthy, I booked the surgery.

Being 46 years old at the time of surgery in 2018, with a 4-year-old pars fracture from 2014 combined with a congenital SBO meant my pars fragment was somewhat atrophied, but it was "very solid", said Dr. Corenman in the operative report. Nevertheless, it was challenging with two things to fix, the pars and SBO, and OR time was around 4 hours. Recovery over the following months was guided by a very clear "Spine binder" from the Steadman Clinic with strict rules of "no BLT" (no bending, lifting or twisting), and illustrated physiotherapy guidelines. They even warned patients to avoid fish oil supplements, which could excessively dampen inflammation and hence slow bone healing. They answered many questions I had during months of recovery, with responses coming from the very supportive Lori Fugate (then director of Dr. Corenman's practice), and Ehrich Bean (then physician's assistant at the practice), as well as a couple calls with Dr. Corenman himself after two of the CT scans. Ehrich Bean offered great advice for taking the spine binder conservatively due to the nature of pars repairs vs. fusions. The final post-op CT scan I had was a couple weeks ago at 34 months post-op, and Dr. Corenman had retired, but I got a very positive and informative call from Eric Strauch (current PA at the Steadman Clinic under Dr. Corenman's replacement there, and who had also worked with Dr. Corenman previously). The staff at the Steadman Clinic were extremely supportive all the way through the process. I should mention, the local Canadian spine surgeon did offer me very good post-operative support including antibiotics as needed to deal with a mild surface incision-site infection early on, booking numerous x-rays when I felt something was amiss, as well as booking all four of my post-op CT scans. I am very grateful for that support also.

My final result shows plenty of solid bone across the pars and a healed SBO, with my vertebral body now a solid bone ring instead of being broken at two places as it was pre-op. Does my spine hold up in the real world? You bet! I have recently dug and moved several yards of dirt and sand and gravel by myself (shovel and wheelbarrow!) to fix our water main, pulled roots from the yard, moved several "portable" (these are HUGE) air conditioners up several flights of stairs my myself, and lifted weights. I now run 2 miles (3.2 KM) several times weekly with a hard 100 meter dash in the middle. I bend deeply before each run I go on, with no spine slippage. My spine feels amazing. I can bend over to do exercise, or real word tasks, with no risk of spine slippage.

My sincere thanks to God, Dr. Donald Corenman, Lori Fugate, Ehrich Bean, Eric Strauch, and the Steadman Clinic, as well as the Canadian spine surgeon who offered me excellent post-operative care back in Canada. You have all given me a new lease on life.

Sincerely,
Eric S

Robert S

May 11, 2021

by Robert S on Donald Corenman, MD, DC

Back Fusion Surgery

I had my entire lumbar spine fused in November of 2018. I had scoliosis , with pinched nerves that were so painful I could hardly walk - and standing for more than a few minutes was impossible. Even sitting was painful.
The fusion surgery produced immediate relief! And the recovery was much easier than I expected.
To this day I can do all the activities I love from hiking, to standing in a stream fly fishing to riding my bike long distances - or just walking down the street with my wife.
Kudos to Dr. Corenman and his staff, (including the two Erics) for taking such good care of me!

Leslie R

Jul 9, 2020

by Leslie R on Donald Corenman, MD, DC

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I had my TLIF surgery on 6/24/2020 by Dr. Corenman, I can not say enough good things about the Dr or his staff. I was always treated with respect and explained everything throughly, that made it easy for everyone to understand. I highly recommend Dr. Corenman and the Steadman Clinic.

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