thoracic outlet syndrome

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More about Thoracic Outlet Syndrome: Causes and symptoms Diagnosis Treatment Prognosis Resources

Definition

Thoracic outlet syndromes are a group of disorders that cause pain and abnormal nerve sensations in the neck, shoulder, arm, and/or hand.

Description

The thoracic outlet is an area at the top of the rib cage, between the neck and the chest. Several anatomical structures pass through this area, including the esophagus, trachea, and nerves and blood vessels that lead to the arm and neck region. The area contains the first rib; collar bone (clavicle); the arteries beneath the collar bone (subclavian artery), which supply blood to the arms, a network of nerves leading to the arms (brachial plexus); and the top of the lungs.

Pain and other symptoms occur when the nerves or blood vessels in this area are compressed. The likelihood of blood vessels or nerves in the thoracic outlet being compressed increases with increased size of body tissues in this area or with decreased size of the thoracic outlet. The pain of thoracic outlet syndrome is sometimes confused with the pain of angina that indicates heart problems. The two conditions can be distinguished from each other because the pain of thoracic outlet syndrome does not appear or increase when walking, while the pain of angina does. Also, the pain of thoracic outlet syndrome usually increases if the affected arm is raised, which does not happen in cases of angina.

There are three types of thoracic outlet syndromes:

• True neurogenic thoracic outlet syndrome is caused by a compression of the nerves in the brachial plexus. Abnormal muscle or other tissue causes the problem.
• Arterial thoracic outlet syndrome is caused by compression of the major artery leading to the arm, usually by a rib.
• Disputed thoracic outlet syndrome describes patients who have chronic pain in the shoulders and arms and have no other disease or syndrome, but the underlying cause cannot be accurately determined.

Thoracic outlet syndrome is most common in women who are 35–55 years of age.

— John T. Lohr, PhD

Any of several syndromes in which blood vessels or nerves are compressed, usually by an overlying muscle, as they pass from the neck region to the arm, causing pain, numbness, and weakness of the arm and hand.

Definition

Thoracic outlet syndrome refers to a condition that results in compression of neurovascular anatomical structures at the superior aperture of the chest (thorax).

Description

Thoracic outlet syndrome (TOS) refers to compression of nerves and blood vessels in the upper portion of the thorax. Neurologic symptoms occur in 95% of affected persons. The cause and treatment of TOS is controversial. In 95% of cases the brachial plexus is involved. The lower two nerves (C8 and T1) are most commonly affected in 90% of persons, following the ulnar nerve distribution. Blood vessels can also be affected. The subclavian vein is involved in 40% of cases and the subclavian artery in 1% of cases. The second most common nerve root involvement occurs in brachial plexus nerves C5, C6, and C7, and symptoms, if these nerves are affected, can be referred to upper back, upper chest, ear, neck, and outer arm that follows a radial nerve distribution.

Demographics

Reports concerning demographic information are controversial and range from three per 1,000 to 80 per 1,000 people. Overall the disorder is three times more common in women than men, with the exception of nervous system involvement which is more common in males. Some reports indicate that TOS is nine times more common in females than males. In the United States the incidence of vascular or neurogenic TOS is considered rare with only one new case per million population for the neurogenic TOS. The usual age of onset is from the second to eighth decade, with a peak age of onset in the fourth decade. Arterial involvement (arterial thoracic outlet syndrome) has no specific gender predilection.

Causes and symptoms

There are three major causes of TOS which include anatomic causes, trauma/repetitive activities, and neurovascular (nerve and blood vessels) entrapment in the chest. Certain anatomic abnormalities of the muscles in the neck and first rib (and a vertebral disk, C7) can cause compression of nerves and arteries. Anatomic abnormalities account for the majority of cases of neurologic and arterial thoracic outlet syndrome. Trauma such as hyperextension injury from motor vehicle accident or effort vein thrombosis (spontaneous thrombosis of the axillary veins following vigorous arm extension) may cause thoracic outlet syndrome. Repetitive activities similar to those of musicians are especially susceptible if they maintain the shoulder in abduction or extension positions for long periods. Nerves and blood vessels can be compressed anatomically in the costoclavicular space between the first rib and the head of the clavicle.

Neurologic pain can occur on either sides of the forearm, upper back and upper chest, neck and ear. Pain is especially evident on the ring and small finger. Patients often experience nocturnal paresthesias, awakening with numbness or pain (dysesthesia). There is often a loss of dexterity, cold intolerance and headache. Venous involvement causes pain, edema (swelling), cyanosis (bluish discoloration of the skin due to lack of oxygen), and distended superficial veins of the shoulder and chest. Arterial involvement causes pain and claudication, pallor, pulselessness, lower blood pressure in affected arm, and embolization (infarcts) of hand and finger. Patients usually have a subtle weakness of affected limb.

Diagnosis

Chest x ray may reveal an anatomic abnormality. Color flow duplex scanning (ultrasound analysis) is indicated for suspected case of vascular thoracic outlet syndrome. If symptoms suggest arterial involvement an arteriogram may be indicated as well as venography (in suspected cases of venous involvement). Nerve conduction evaluation by nerve root stimulation is the best approach to diagnose neurologic thoracic outlet syndrome.

Treatment team

The treatment team usually consists of appropriate specialists which depend on the presentation. Specialists that can be consulted include a neurologist, vascular surgeon or orthopedic surgeon. Physical medicine physicians are required for outpatient workup and evaluation.

Treatment

Neurologic TOS requires outpatient referral and conservative outpatient physiotherapy. Vascular thoracic outlet syndrome requires more urgent care that typically includes immediate heparinization, vascular surgery consultation, color flow (ultrasound), duplex scanning and angiography or venography. Neurologic thoracic outlet syndrome patients may also require surgery if conservative medical therapy fails for more than four months. However, surgical results are not encouraging since a study demonstrated that 60% of postsurgical patients were still work disabled one year after surgery. Outpatient medications can include Coumadin (a blood thinner or anticoagulant), analgesics or short-term antidepressants if there is protracted pain.

Recovery and rehabilitation

Recovery includes stress avoidance and work simplification and modifications on the job site. Recommendations include avoidance of sustained muscular contraction and repetitive or overhead work. Exercise programs may help with chronic pain. Exercises are recommended to maximize the potential outlet space through special stretching and strengthening maneuvers of the shoulder. These exercise can include maneuvers such as bilateral (both sides) shoulder retraction while standing or lying prone, standing corner pushups, hand circles and cervical and lumbar spine extension. Outpatient management typically includes occupational/physical therapy, and manipluation. Inpatient treatment is not indicated unless the patient is a surgical candidate.

Clinical trials

There are projects funded by the National Institute of Neurological Diseases and Stroke concerning pain and pain management. The projects forcus on seeking new treatments for nerve damage and pain.

Prognosis

Neurologic TOS is not progressive and but requires treatment. Arterial or venous thoracic outlet syndrome respond well to adequate treatment and the results are generally good. Some patients can develop chronic pain (neurologic type) or thrombosis (venous and arterial thoracic outlet syndrome). Other complications that can develop include loss of functional ability of arms, neurologic deficit, depression, and ischemia.

Special concerns

Pregnancy can cause an increase in TOS symptoms, because of increased body size and displacement of the abdomen. Increased breast size common during and after pregnancy can displace the shoulder girdle and cause postural changes that can precipitate symptoms. Patients should be educated concerning precipitating factors of TOS, which can decrease the likihood of recurrence.

Resources

BOOKS

Goetz, Christopher G., et al., eds. Textbook of Clinical Neurology, 1st ed. Philadelphia: W. B. Saunders Company, 1999.

Marx, John A., et al., eds. Rosen's Emergency Medicine: Concepts and Clinical Practice, 5th ed. St. Louis: Mosby, Inc., 2002.

Townsend, Courtney M. Sabiston Textbook of Surgery, 16th ed. W. B. Saunders Company, 2001.

WEBSITES

National Rehabilitation Information Center. http://www.naric.com.

ORGANIZATIONS

American Chronic Pain Association. P.O. Box 850, Rocklin, CA 95677-0850. (916) 632-0922 or (800) 533-3231; Fax: (916) 632-3208. ACPA@pacbell.net. http://www.theacpa.org.

Laith Farid Gulli, MD

Nicole Mallory, MS, PA-C

Alfredo Mori, MBBS

Thoracic outlet syndrome
Classification and external resources
The right brachial plexus with its short branches, viewed from in front.
ICD-10	G54.0
ICD-9	353.0
DiseasesDB	13039
MedlinePlus	001434
eMedicine	pmr/136
MeSH	D013901

Thoracic outlet syndrome (TOS) consists of a group of distinct disorders involving compression at the superior thoracic outlet^[1] that affect the brachial plexus (nerves that pass into the arms from the neck), and/or the subclavian artery and vein (blood vessels that pass between the chest and upper extremity).

Contents 1 Causes 2 Classification 3 Diagnosis 4 Treatment 4.1 Noninvasive 4.2 Invasive 5 Notable patients 6 References 7 External links

Causes

For the most part, these disorders are produced by compression of the components of the brachial plexus (the large cluster of nerves that pass from the neck to the arm), the subclavian artery, or the subclavian vein.^[2] These subtypes are referred to as neurogenic TOS (NTOS),^[3] arterial TOS, and venous TOS, respectively. The compression may be positional (caused by movement of the clavicle (collarbone) and shoulder girdle on arm movement) or static (caused by abnormalities or enlargement of the various muscles surrounding the arteries, veins and brachial plexus).

The neurogenic form of TOS accounts for 95% of all cases of TOS.^[4]

It is known from pathological studies of cadavers, and from surgical studies of patients with TOS, that there are numerous anomalies of the scalene muscles and the other muscles that surround the arteries, veins and brachial plexus. TOS may result from these anomalies of the scalene muscles or from enlargement (hypertrophy) of the scalene muscles. One common cause of hypertrophy is trauma, as may occur in motor vehicle accidents.

The two groups of people most likely to develop TOS are those suffering neck injuries in motor vehicle accidents and those who use computers in non-ergonomic postures for extended periods of time. Young overhead athletes (such as swimmers, volleyball players and baseball pitchers) and musicians may also develop thoracic outlet syndrome, but significantly less frequently than the two large groups above.

Classification

The following taxonomy of TOS is used in ICD-9-CM and older sources:

• Scalenus anticus syndrome (compression on brachial plexus and/or subclavian artery caused by muscle growth) - diagnosed by using Adson's sign with patient's head turned outward
• Cervical rib syndrome (compression on brachial plexus and/or subclavian artery caused by bone growth) - diagnosed by using Adson's sign with patient's head turned inward
• Costoclavicular syndrome (narrowing between the clavicle and the first rib) -- diagnosed with costoclavicular maneuver

A more modern system of classification is provided on the website of the National Institute of Neurological Disorders and Stroke (NINDS).^[5]

Diagnosis

Adson's sign and the costoclavicular maneuver are notoriously inaccurate, and may be a small part of a comprehensive history and physical examination of a patient with TOS. There is currently no single clinical sign that makes the diagnosis of TOS with certainty. Arteriography, while only rarely used to evaluate thoracic outlet syndrome, may be used if a surgery is being planned to correct an arterial TOS.^[6]

Treatment

Often, continued and active postural changes along with physiotherapy, massage therapy, chiropractic or osteopathic manipulation, will suffice. The recovery process however is long term, and a few days of poor posture can often set one back.

About 10 to 15% of patients undergo surgical decompression following an appropriate trial of conservative therapy, most often specific physical therapy directed towards the treatment of thoracic outlet syndrome, and usually lasting between 6 and 12 months. Surgical treatment may include removal of anomalous muscles, removal of the native anterior and/or middle scalene muscles, removal of the first rib or, if present, a cervical rib, or neurolysis (removal of fibrous tissue from the brachial plexus).

Noninvasive

• Stretching
  The goal of self stretching is to relieve compression in the thoracic cavity, reduce blood vessel and nerve impingement, and realign the bones, muscles, ligaments, and tendons causing the problem.
  • Moving shoulders forward (hunching) then back to neutral, followed by extending them back (arching) then back to neutral, followed by lifting shoulders then back to neutral.
  • Tilting and extending neck opposite to the side of injury while keeping the injured arm down or wrapped around the back.
• Nerve Gliding
  This syndrome causes a compression of a large cluster of nerves, resulting in the impairment of nerves throughout the arm. By performing nerve gliding exercises one can stretch and mobilize the nerve fibers. Chronic and intermittent nerve compression has been studied in animal models, and has a well-described pathophysiology, as described by Susan Mackinnon, MD, currently at Washington University in St. Louis. Nerve gliding exercises have been studied by several authorities, including David Butler in Australia.
  • Extend your injured arm with fingers directly outwards to the side. Tilt your head to the otherside, and/or turn your head to the other side. A gentle pulling feeling is generally felt throughout the injured side. Initially, only do this and repeat. Once this exercise has been mastered and no extreme pain is felt, begin stretching your fingers back. Repeat with different variations, tilting your hand up, backwards, or downwards.
• Posture
  TOS is rapidly aggravated by poor posture. Active breathing exercises and ergonomic desk setup can both help maintain active posture. Often the muscles in the back become weak due to prolonged (years) hunching.
• Ice/Heat
  Ice can be used to decrease inflammation of sore or injured muscles. Heat can also aid in relieving sore muscles by improving circulation to them. While the whole arm generally feels painful, some relief can be seen when ice/heat is applied to the thoracic region (collar bone, armpit, or shoulder blades).

Invasive

• Cortisone
  Injected into a joint or muscle, cortisone can help relief and lower inflammation.^{[dubious – discuss]}
• Botox injections
  Short for Botulinum Toxin A, Botox binds nerve endings and prevents the release of neurotransmitters that activate muscles. A small amount of Botox injected into the tight or spastic muscles (usually one or all three scalenes) found in TOS sufferers often provides months of relief while the muscle is temporarily paralyzed. This noncosmetic treatment is unfortunately not covered by most medical plans and costs upwards of $400. The relief of symptoms from a Botox injection generally lasts 3–4 months, at which point the Botox toxin is degraded by the affected muscles. Serious side effects have been reported, and are similarly long-lasting, so improved understanding of the mechanism of a 'scalene block' is vital to determining the benefit and risk of using Botox.

Surgical approaches have also been used.^[7]

Some physicians advocate the injection of a short-acting anesthetic such as xylocaine into the anterior scalene, subclavius, or pectoralis minor muscles as a provocative test to assist in the diagnosis of thoracic outlet syndrome. This is referred to as a 'scalene block'. If the patient experiences symptomatic relief for approximately 15 minutes following this procedure, surgical decompression is more likely to be successful in leading to the same level of symptomatic relief. However, this is not considered a 'treatment', as the relief is expected to wear off within an hour or two, at a maximum. Active research continues into the accuracy and risks of this provocative test.

Notable patients

Major League Baseball players Hank Blalock, John Rheinecker, Jeremy Bonderman, Kenny Rogers and Noah Lowry^[8] have recently been diagnosed with Thoracic outlet syndrome. Kenny Rogers was diagnosed several years earlier with TOS in the other upper extremity. Coincidentally, three of these five players have played for the Texas Rangers. All-Star pitcher J. R. Richard suffered a career-ending stroke from an undiagnosed case of TOS. Pitcher David Cone had a variant case of TOS, with an arterial aneurysm of the upper aspect of his pitching arm.

Overhead athletes, such as swimmers and volleyball players, are known to be predisposed to the development of TOS.

Musician Isaac Hanson suffered a potentially life threatening pulmonary embolism as a complication to thoracic outlet syndrome.^[9]

References

1. ^ MeSH Thoracic+outlet+syndrome
2. ^ thoracic outlet syndrome at Dorland's Medical Dictionary
3. ^ Ambrad-Chalela E, Thomas GI, Johansen KH (April 2004). "Recurrent neurogenic thoracic outlet syndrome". Am. J. Surg. 187 (4): 505–10. doi:10.1016/j.amjsurg.2003.12.050. PMID 15041500. http://linkinghub.elsevier.com/retrieve/pii/S0002961003006445. 
4. ^ Fugate MW, Rotellini-Coltvet L, Freischlag JA (April 2009). "Current management of thoracic outlet syndrome". Curr Treat Options Cardiovasc Med 11 (2): 176–83. PMID 19289030. http://www.treatment-options.com/1092-8464/11/176. 
5. ^ NINDS Thoracic Outlet Syndrome Information Page
6. ^ Thoracic outlet syndrome Mount Sinai Hospital, New York
7. ^ Rochkind S, Shemesh M, Patish H, et al. (2007). "Thoracic outlet syndrome: a multidisciplinary problem with a perspective for microsurgical management without rib resection". Acta Neurochir. Suppl. 100: 145–7. PMID 17985565. 
8. ^ San Francisco Chronicle: Lowry's agent lashes out
9. ^ "People Magazine". http://www.hanson.net/site/hanson/blog_entry/1?entry_id=5832. Retrieved on 2008-01-01. 

External links

• thoracic at NINDS
• American Thoracic Outlet Syndrome Association
• Journal of American Chiropractic Association
• Physical Therapy Corner - Thoracic Outlet Syndrome
• Society for Vascular Surgery (U.S.)
• Thoracic Outlet Syndrome Patient Information
• Division of Vascular Surgery and Endovascular Therapy at the Baylor College of Medicine

v • d • e Nervous system pathology, PNS (G50-G64, 350-357) Somatic Nerve, nerve root, plexus Cranial nerve disease V (Trigeminal neuralgia) · VII (Facial nerve paralysis, Bell's palsy, Melkersson-Rosenthal syndrome, Central seven) · XI (Accessory nerve disorder) Radiculopathy, plexopathy brachial plexus (Brachial plexus lesion, Thoracic outlet syndrome) · Phantom limb Mono- neuropathy Upper limb median nerve (Carpal tunnel syndrome) ulnar nerve (Ulnar nerve entrapment, Froment's sign, Guyon's canal syndrome, Ulnar claw) radial nerve (Radial neuropathy, Wrist drop) long thoracic nerve (Winged scapula) Lower limb lateral cutaneous nerve of thigh (Meralgia paraesthetica) · tibial nerve (Tarsal tunnel syndrome) · plantar nerve (Morton's neuroma) superior gluteal nerve (Trendelenburg's sign) General Causalgia · Mononeuritis multiplex Polyneuropathies/ Polyradiculoneuropathy HMSN Charcot-Marie-Tooth disease · Dejerine Sottas syndrome · Refsum's disease · Hereditary spastic paraplegia Autoimmune/demyelinating Guillain-Barré syndrome · Chronic inflammatory demyelinating polyneuropathy Other Alcoholic polyneuropathy Dysautonomia, autonomic- neuropathy HSAN (I, II, III/Familial dysautonomia, IV/Congenital insensitivity to pain with anhidrosis, V) · Horner's syndrome · Multiple system atrophy

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