Thoracic outlet syndrome
Dr. Richard J Sanders, author of the book "Thoracic Outlet Syndrome", describes the cause,diagnosis, and treatment of TOS.
Definition
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 95% 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. During the year 2005, we have become aware of a large number of patients who, in addition to these symptoms, also have pain in the anterior chest wall, just below the collar bone along with pain over the shoulder blade. Until recently it was thought that these later symptoms were also due to TOS, but now it has been learned that they are due to a condition frequently accompanying TOS, namely pectoralis minor syndrome.
Cause
TOS is most often produced by hyperextension neck injuries. Auto accidents that cause whiplash injuries, 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.
Diagnosis
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. 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 (biceps tendon). Pressure on this spot often causes pain and tingling down the arm.
Diagnostic tests, such as EMG's or NCV's, may show non-specific abnormalities, but in most people with TOS, these tests are normal. However, during 2005 we found a new nerve test which has been abnormal in the large majority of TOS and pectoralis minor syndrome patients. 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. We have completed a paper describing our experiences with this test in 41 patients and have submitted it to a medical journal for publication.
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 these positions. Shrinkage of hand muscles (atrophy) occurs in about 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.
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.
Treatment
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, 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, but it should be regarded as a last resort. Non-surgical forms of treatment should always be tried first.
Surgical
Treatment
Surgery for TOS is designed to take pressure off the nerves to the arm. This 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. In the year 2004, during which time over 100 operations were performed, the first rib was removed in 7 patients.
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 stayed in the body for several months rather than just 4 weeks. We have now used this newer material in some 100 patients and are seeing fewer recurrences to date.
In 2005 we became acquainted with a condition that was described 60 years ago but which most of us had ignored, the pectoralis minor syndrome (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 at least half the people who have TOS also have complaints and positive physical exam findings of pectoralis minor syndrome. If following a pectoralis minor 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 through a 3 inch incision in the arm pit. The pectoralis minor muscle is easily found and cut at its attachment to the shoulder blade (at the coracoid process). One inch of the muscle is then removed to prevent it's reattachment to the top of the nerves going to the arm. The incision is closed with buried stitches. The operation usually takes less than 30 minutes and can be performed as an outpatient and recently we have found that this procedure can be performed 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.
In 2005 and 2006, we performed 130 pectoralis minor tenotomies as the only operation. 60 of these were performed in patients who previously had been operated upon by scalenectomy or first rib resection. They had experienced partial improvement in their symptoms from their operation but continued to complain of pain in the chest and pain over the shoulder blade.
Separately, 70 pectoralis tenotomies have been performed on patients who had not been operated upon previously. They had been seen because it was thought they had TOS. On exam, most of them did indeed have TOS, but also had findings of pectoralis minor syndrome. When their symptoms and findings on physical exam were dramatically improved by a pectoralis minor block, they were offered the simple operation of pectoralis minor tenotomy with the understanding that if they did not experience good relief of their symptoms they could return for the bigger operation of scalenectomy or first rib resection. To date, 6 patients have returned and received scalenectomies. The other 64 have had enough improvement that consideration of additional surgery has not been necessary.
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. Auto injuries have a success rate of about 80% while repetitive stress at work has a success rate of 65-70%. Pectoralis minor tenotomy has only been performed for the past two years. The success rate to date is over 80%.
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.,
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.
Last updated: April 2007