Thoracic outlet syndrome--Dr. Richard Sanders

Dr. Richard J Sanders, author of the book "Thoracic Outlet Syndrome", describes the cause,

diagnosis, and treatment of TOS.


Thoracic Outlet Syndrome (TOS) is pain, numbness, tingling, and/or weakness in the arm and hand due to pressure against the nerves or blood vessels that supply the arm. It is due to tight muscles, ligaments, bands, or bony abnormalities in the thoracic outlet area of the body, which lies just behind the collar bone. Pressure on the nerves is the problem more than 90% of the time, but occasionally the artery or vein is involved.

Common Symptoms

The most frequent complaints are numbness and tingling in the fingers; pain in the neck, shoulder, and arm; headaches in the back of the head; weakness of the arm and dropping things from the hand; worsening of the symptoms when elevating the arm to do such things as comb or blow dry one's hair or drive a car; and coldness and color changes in the hand. The symptoms are often worse at night or when using the arm for work or other activities.

In 2005 we became aware of a large number of patients who, in addition to these symptoms, also had pain in the anterior chest wall, just below the collar bone along with pain over the shoulder blade and in the arm pit. Until recently it was thought that these symptoms were due to TOS, but now it has been learned that they are due to a condition frequently accompanying TOS, namely pectoralis minor syndrome.


TOS is most often produced by hyperextension neck injuries. Whiplash injuries from auto accidents and repetitive stress in the workplace, are the two most common causes. Some of the occupations that we see causing TOS include working on assembly lines, keyboards, or 10-key pads, as well as filing or stocking shelves overhead. In some people, symptoms develop spontaneously, without an obvious cause. An extra rib in the neck occurs in less than 1% of the population. People born with this rib, called a "cervical rib", are 10 times more likely to develop symptoms of TOS than other people. However, even in men and women with cervical ribs, it usually requires some type of neck injury to bring on the symptoms. Pectoralis minor syndrome appears in more than half of the patients who have TOS. It results from the same type of injuries that cause TOS.


Physical examination is most helpful. Common findings are tenderness over the scalene muscles, located about one inch to the side of the wind pipe. Pressure on this spot causes pain or tingling down the arm. Rotating or tilting the head to one side causes pain in the opposite shoulder or arm plus tingling in the hand Elevating the arms in the "stick-em-up" position reproduces the symptoms of pain, numbness, and tingling in the arm and hand. There is often reduced sensation to very light touch in the involved hand (this can only be detected in people with involvement on one side).

In addition to these findings on physical examination of patients with TOS , patients with pectoralis minor syndrome have tenderness just below the collar bone about an inch or two inside the shoulder. Pressure on this spot often causes pain and tingling down the arm. Also, patients with pectoralis minor syndrome often have tenderness in the armpit.

Diagnostic tests, such as EMG's or NCV's, may show non-specific abnormalities, but usually are normal in people with TOS. However, recently a new nerve test was found which has been abnormal in the large majority of patients with neurogenic TOS and pectoralis minor syndrome. This test can be considered a variation of EMG/NCV measurements. It is a determination of the medial antebrachial cutaneous nerve (abbreviated MAC). It is one of the few objective tests that can support the diagnosis.(Reported recently by Machanic, BI and Sanders, RJ in the Annals of Vascular Surgery,March,2008.)

Neck or chest x-rays may show a cervical rib. Loss of the pulse at the wrist when elevating the arm or when turning the neck to the side (Adson's sign), has been thought by some to be an important diagnostic sign. However, we find it unreliable because many normal people also lose their pulse in the same positions, and the majority of people with TOS do not lose their pulse in this position. Shrinkage of hand muscles (atrophy) occurs in only 1% of people with TOS, and these people will have nerve tests that show a typical pattern of ulnar nerve damage.

Other diagnostic tests that are helpful are a scalene muscle block for TOS and a pectoralis minor muscle block for the pectoralis minor syndrome. These are simple office tests that involve a 15 second injection of xylocaine into the anterior scalene or pectoralis minor muscle. The tests give strong support to the correct diagnosis if within a minute or two of the injection there is good relief of symptoms and improvement in physical exam findings.

Imaging by MRI is currently being investigated in a few centers for its value in diagnosing TOS. While subtle deviations from normal patterns are being recognized, their significance in guiding treatment has not yet been established. As of 2008, specific diagnostic criteria with this technique are still in the investigative stage.

Disease Process

Microscopic examination of scalene muscles from the necks of people with TOS demonstrates scar tissue throughout the muscle. Presumably, this was caused by a neck injury stretching these muscle fibers. The tight muscles then press against the nerves to the arm (brachial plexus) producing the hand and arm symptoms. Neck pain and headaches in the back of the head may be caused by the tightness in these muscles but also can be the result of stretching muscles and ligaments along the cervical spine of the neck in cases of whiplash injury.


Physical Therapy

Treatment begins with physical therapy and neck stretching exercises. Abdominal breathing, posture correction, and nerve glides, carried out on a daily basis, are a part of the therapy program. Gentle, slow movements and exercises are stressed. Methods like Feldenkrais have helped many people with TOS. Modalities to avoid are those that emphasize strengthening exercises, such as therabands, heavy weights, and painful stretching. It is important to be examined and tested for other causes of these symptoms because other conditions can coexist with TOS, and these should be identified and treated separately. Some of these associated conditions include carpal tunnel syndrome, ulnar nerve entrapment at the elbow, shoulder tendinitis and impingement syndrome, fibromyalgia of the shoulder and neck muscles, and cervical disc disease. Surgery can be performed for TOS and pectoralis minor syndrome, but it should be regarded as a last resort. Non-surgical forms of treatment should always be tried first.

Surgical Treatment

Thoracic outlet surgery: This is designed to take pressure off the nerves to the arm and can be achieved by removing the muscles that surround the nerves (scalene muscles), by removing the first rib, or by doing both (removing muscles and first rib). Over the past 30 years we have employed each of these 3 operations in a quest for the safest and most effective procedure. All 3 procedures (transaxillary first rib resection, scalenectomy, and combined rib resection and scalenectomy) have limitations; there is no perfect operation. When we analyzed our results for the 1990's, it was observed that the failure rate for scalenectomy with rib resection or without rib resection was the same. This has led us to use scalenectomy without rib resection as our operation of choice. However, when during the operation we observe the nerves to the arm being pressed by the first rib, we will remove the rib during that operation.

Recurrent symptoms of pain, numbness and tingling is most often the result of scar tissue formation during the healing period. This occurs regardless of which operation is performed. Between in 2002 and 2004, we used a material like Saran wrap to cover the nerves to the arm to reduce scar tissue adhering to the nerves after surgery in 250 operations. This material was totally absorbed in the body in 4 weeks, so there was no foreign body remaining. When we analyzed the results with this material, we found that although it did reduce the amount of scar tissue making reoperations for recurrence easier, it did not significantly reduce the incidence of recurrent symptoms. Therefore, beginning in 2005, we changed the material to a similar one that now stays in the body for several months rather than just 4 weeks. By 2008, this newer material had been used in over 200 patients and to date the number of failures has been cut in half.

Pectoralis minor surgery: In 2005 we became acquainted with the pectoralis minor syndrome, a condition that was described 60 years ago but which most of us had ignored (described above under "cause" and "diagnosis"). Each patient we now see for TOS is also examined for this. We have been surprised to find that over 75% of the people who have TOS also have complaints and positive physical exam findings of pectoralis minor syndrome. If following a pectoralis minor muscle block there is significant improvement within a few minutes, we have been performing a very simple operation called pectoralis minor tenotomy. This operation is performed as an outpatient under local anesthesia, but with an anesthesiologist in attendance so that patients are asleep for a short time but are awake within a few minutes of the end of the operation. The procedure carries almost no risk of injury.

Between 2005 and 2007, 300 operations were performed that included the pectoralis minor muscle. Half of these were pectoralis minor operations alone; the other half combined pectoralis minor release with thoracic outlet operations.

Deciding who has thoracic outlet syndrome and who has pectoralis minor syndrome is determined by history, physical exam, and muscle blocks. Patients who are diagnosed with pectoralis minor syndrome alone are offered pectoralis minor release as the only operation. Those who are diagnosed with both conditions, and who note significant improvement following pectoralis minor block, are offered the simple operation of pectoralis minor tenotomy with the understanding that if they do not experience good relief of their symptoms they can return for the bigger operation of scalenectomy or first rib resection. To date, 14 of the first 48 patients with both TOS and pectoralis minor syndrome woe received pectoralis minor tenotomies alone have returned and received scalenectomies, some with first rib resection but most without rib resection.

In another group of patients, who have predominately TOS, but also have pectoralis minor syndrome, surgery has consisted of both TOS and pectoralis minor operations. By combining the two operations under the same anesthetic it has been possible to improve the success rate for surgery.

Results of Treatment

Most people with TOS will improve with stretching and physical therapy. In our experience with over 5000 people with TOS, less than 30% had surgery.

The improvement rate with surgery varies with the cause of the TOS. Prior to 2005, auto injuries had a success rate of about 80% while repetitive stress at work has a success rate of 65-70%. Since adding pectoralis minor release to thoracic outlet operations and wrapping nerves during surgery with a plastic film, the success rate has increased to over 85% in both groups.

Pectoralis minor tenotomy as the only operation has two different success rate. Patients whose diagnosis is only pectoralis minor syndrome have a success rate to date of 90%. In patients with both pectoralis minor syndrome and thoracic outlet syndrome, the success rate for pectoralis minor tenotomy alone is only 50%. More than half of these patients have returned to have a thoracic outlet operation a later date. Following the second operation the success rate has been over 85%.

Recurrent thoracic outlet syndrome

Recurrent symptoms after thoracic outlet operations, either rib resection or scalenectomy, are frequently due to pectoralis minor syndrome. In the past 3 years more than 100 patients have been operated upon for recurrence. Most of these patients received the simple operation of pectoralis minor release. A smaller number of patients required combined thoracic outlet reoperations plus pectoralis minor release. The success rate in both groups of patients has been over 70%.

For more Information

More information regarding TOS is available in the book: THORACIC OUTLET SYNDROME: A COMMON SEQUELA OF NECK INJURIES. Written by Richard J. Sanders, M.D. and Craig E. Haug, M.D., the book was first published by J.B. Lippincott Co., Philadelphia, in 1991. Lippincott elected not to reprint the book when it sold out its first printing. However, the publisher has given permission to the author to reprint the book and it is now available by phoning his office, toll free, 1-888-756-6222. If you would like to discuss your TOS problem, feel free to call the author, Dr. Richard Sanders, M.D., in Denver at 303 388-6461, or call toll free, 1-888-756-6222.

Dr. Sanders is Board certified in both General Surgery and Vascular Surgery. In addition to his book on TOS, he has authored several articles in medical journals and many chapters in surgical textbooks on the subject of TOS. He has been treating patients with TOS for over 30 years. During this time he has seen over 5000 patients with TOS and performed over 2000 operations for this condition. Since 2005 he has treated more than 300 patients with pectoralis minor syndrome.

Last updated: September 2008