Sedentary Work Exerting up to 10 pounds (4.5 kg) of force occasionally and/or a negligible amount of force frequently or constantly to lift, carry, push, pull, or otherwise move objects, including the human body. Sedentary work involves sitting most of the time, but may involve walking or standing for brief periods of time. Jobs are sedentary if walking and standing are required only occasionally and other sedentary criteria are met.

Light Work Exerting up to 20 pounds (9.1 kg) of force occasionally and/or up to 10 pounds (4.5 kg) of force frequently, and/or negligible amount of force constantly to move objects. Physical demand requirements are in excess of those for Sedentary Work. Light Work usually requires walking or standing to a significant degree. However, if the use of the arm and/or leg controls requires exertion of forces greater than that for Sedentary Work and the worker sits most the time, the job is rated Light Work.

Medium Work Exerting up to 50 (22.7 kg) pounds of force occasionally, and/or up to 25 pounds (11.3 kg) of force frequently, and/or up to 10 pounds (4.5 kg) of forces constantly to move objects.

Heavy Work Exerting up to 100 pounds (45.4 kg) of force occasionally, and/or up to 50 pounds (22.7 kg) of force frequently, and/or in excess of 20 pounds (9.1 kg) of force constantly to move objects.

Very Heavy Work Exerting in excess of 100 pounds (45.4 kg) of force occasionally, and/or in excess of 50 pounds (22.7 kg) of force frequently, and/or in excess of 20 pounds (9.1 kg) of force constantly to move objects.

Job Classification

In most duration tables, five job classifications are displayed. These job classifications are based on the amount of physical effort required to perform the work. The classifications correspond to the Strength Factor classifications described in the United States Department of Labor's Dictionary of Occupational Titles. The following definitions are quoted directly from that publication.

Sedentary Work Exerting up to 10 pounds (4.5 kg) of force occasionally and/or a negligible amount of force frequently or constantly to lift, carry, push, pull, or otherwise move objects, including the human body. Sedentary work involves sitting most of the time, but may involve walking or standing for brief periods of time. Jobs are sedentary if walking and standing are required only occasionally and other sedentary criteria are met.

Light Work Exerting up to 20 pounds (9.1 kg) of force occasionally and/or up to 10 pounds (4.5 kg) of force frequently, and/or negligible amount of force constantly to move objects. Physical demand requirements are in excess of those for Sedentary Work. Light Work usually requires walking or standing to a significant degree. However, if the use of the arm and/or leg controls requires exertion of forces greater than that for Sedentary Work and the worker sits most the time, the job is rated Light Work.

Medium Work Exerting up to 50 (22.7 kg) pounds of force occasionally, and/or up to 25 pounds (11.3 kg) of force frequently, and/or up to 10 pounds (4.5 kg) of forces constantly to move objects.

Heavy Work Exerting up to 100 pounds (45.4 kg) of force occasionally, and/or up to 50 pounds (22.7 kg) of force frequently, and/or in excess of 20 pounds (9.1 kg) of force constantly to move objects.

Very Heavy Work Exerting in excess of 100 pounds (45.4 kg) of force occasionally, and/or in excess of 50 pounds (22.7 kg) of force frequently, and/or in excess of 20 pounds (9.1 kg) of force constantly to move objects.

Thoracic Outlet Syndrome


Related Terms

  • Anterior Scalene Syndrome
  • Brachial Plexus Lesion Disorder
  • Cervical Rib Syndrome
  • Thoracic Outlet Compression Syndrome

Differential Diagnosis

Specialists

  • Anesthesiologist
  • Neurologist
  • Neurosurgeon
  • Occupational Therapist
  • Orthopedic (Orthopaedic) Surgeon
  • Physical Therapist
  • Rheumatologist
  • Thoracic Surgeon

Comorbid Conditions

Factors Influencing Duration

Length of disability will be determined by the severity of symptoms, whether the dominant or non-dominant side is affected, whether surgery is required, and outcome of treatment.

Medical Codes

ICD-9-CM:
353.0 - Brachial Plexus Lesions; Cervical Rib Syndrome; Costoclavicular Syndrome; Scalenus Anticus Syndrome; Thoracic Outlet Syndrome

Overview

© Reed Group
Thoracic outlet syndrome (TOS) refers to a spectrum of disorders encompassing three interrelated and uncommon syndromes. The first, neurogenic TOS, arises from compression of the nerves (brachial plexus) in the base of the neck. The second, vascular TOS, arises from compression of the arteries and veins under the collarbone (subclavian) or arm (axillary). The third syndrome, sometimes called disputed neurogenic TOS, arises from nerve compression of less specific origin and accounts for the majority of surgical treatments for TOS in the US. Neurogenic TOS is most common, accounting for 95% of cases, followed by vascular TOS, where compression of the subclavian vein accounts for 4% of cases, and compression of the subclavian artery accounts for 1% of cases (Chang; Povlsen).

The most common cause of these syndromes is trauma, either from direct trauma to the neck or from the irritating presence of an incomplete extra rib (cervical rib) above the normal first rib. An aberrant or rudimentary rib narrows the space under the collar bone (clavicle) and can press on the brachial plexus or cause intermittent compression of the subclavian artery or the subclavian vein corresponding with arm movement. Cervical ribs are normally asymptomatic, however, and the presence of a cervical rib does not automatically explain TOS symptoms.

TOS almost always occurs in adulthood, suggesting that compression occurs over time as the muscles and ligaments in this area undergo changes with age and / or use. Many individuals with TOS are women in early or mid-adult life in whom sagging of the shoulders, large breasts, and poor muscular tone (hypotonia) may be a contributing factor.

TOS also may be the result of traumatic injury in an auto accident (e.g., whiplash of the neck). Individuals born with cervical and anomalous first ribs—an estimated 1% of the population—who experience neck trauma as the result of injury or repetitive stress are pre-disposed to developing TOS (Sanders).

Incidence and Prevalence: Difficulty in establishing diagnosis, the variety of contributing factors, and the necessity of ruling out other causes of symptoms, make estimating the overall incidence of TOS particularly controversial. Reports range from 3 per 1,000 to 80 per 1,000 people (Chang), while other authors estimate the occurrence of true or classical neurogenic or vascular TOS to be as rare as 1 in 1 million people (Sucher).

Source: Medical Disability Advisor



Causation and Known Risk Factors

TOS is three times more common in females than in males; however, TOS caused by compression of the subclavian vein is more common in men. Symptoms usually appear between the ages of 20 and 50 years (Chang).

Individuals most likely to be affected include construction workers, carpenters, repairmen, and others who are required to lift heavy materials throughout the day. Athletes who experiences injuries to the neck or shoulder during contact sports such as rugby or football also may develop TOS.

Source: Medical Disability Advisor



Diagnosis

History: Individuals report pain in the neck, shoulder, arm, and hand, or in all four locations. In neurogenic TOS, hand pain can be severe in the fourth and fifth fingers. Individuals may report that the pain is aggravated by use of the arm, and fatigue of the arm is often marked. Tingling and pain (paresthesia) may be enough to awaken individuals from sleep. Other symptoms may include recurrent headaches, particularly in the back of the head (occipital headaches), and neck pain. Individuals experiencing venous TOS also may report swelling of the arm, a bluish tinge to skin (cyanosis), and coldness of the affected arm and hand. Arterial TOS often is not detected until migration of a blood clot obstructs an artery (thromboembolic event). Some individuals may report a history of neck trauma preceding symptoms, usually from an auto accident or repetitive work activity.

Physical exam: True neurogenic and vascular TOS are uncommon and such a diagnosis should be made cautiously. Physical signs are not always obvious. The exam should include careful palpation of the scalene muscles as well as the supraclavicular artery and vein. There may be tenderness in the area above the clavicle or abnormal pulsations from the vasculature. Symptoms often can be reproduced by pressure on the scalene muscles on the affected side combined with movement of the arm away from the body (abduction) and external rotation of the arm. During these maneuvers, the radial pulse in the wrist may diminish or disappear (Adson's sign); however since this sign can also occur in up to 50% of individuals without TOS, it is no longer considered distinctly characteristic of TOS. The fingers may turn cyanotic when the arm is raised overhead. One of the most important aspects of the physical exam is to diagnose or rule out other problems of the neck and arm.

A psychiatric evaluation often assists providers identify symptoms of depression or somatoform disorder which are commonly present.

Tests: X-rays of the cervical spine can confirm the presence of a cervical rib. A CT scan can help rule out cervical disk disease, spinal stenosis, or tumors of the upper lung. Nerve conduction studies may reveal decreased sensory potentials in individuals with neurogenic TOS. Vascular tests such as brachial artery angiography are usually reserved for individuals with suspected arterial blockage or a dilation of the wall of a blood vessel (aneurysm). Venography or noninvasive vascular tests such as Doppler ultrasonography can help assess vascular status if a blockage in a vein (venous thrombosis) is suspected. An MRI of the cervical spine and supraclavicular/brachial area may be useful to identify other causes of symptoms.

Source: Medical Disability Advisor



Treatment

For neurogenic TOS, a trial of 3 to 12 months of conservative treatment directed toward correction of abnormal posture or muscle imbalance is the most accepted approach, even if an operative procedure is anticipated. Conservative treatment seeks to reduce and redistribute pressure on affected nerves and blood vessels and may include an exercise program, manual therapy to increase mobility of the shoulder girdle, shoulder braces to improve posture, or alterations to customary work habits. Physical activities that aggravate the condition should be avoided. Nonsteroidal anti-inflammatory drugs (NSAIDs) or muscle relaxants are sometimes useful in relieving pain. An anterior scalene block can be performed to anesthetize the anterior scalene muscle, indirectly relieving pressure on the brachial plexus. Typically, this treatment is used to confirm the diagnosis and assess whether the individual may be a candidate for thoracic outlet decompression surgery, but it also may be therapeutic. The reliability, accuracy, and safety of this potentially dangerous procedure may be enhanced with the use of electrophysiologic guidance to verify needle tip placement.

Surgery is usually reserved for those individuals with neurogenic TOS who have failed to improve with conservative management and are unable to live and work comfortably. Surgery involves releasing or removing the structures that cause the compression. The procedure could include releasing the scalene muscle (scalenectomy), removal of an accessory rib, or removing all or part of the first rib (rib resection). In extreme cases, breast reduction surgery may prove helpful in reducing the weight load to the anterior chest wall, thereby helping to relieve symptoms. A second opinion is often helpful before surgery is performed.

There are no satisfactory medical treatments for arterial TOS; prompt surgical intervention is required to decompress the thoracic outlet and repair the artery.

Medical treatment of venous TOS consists of anticoagulant (thrombolytic) therapy and arm elevation; surgical removal of blood clots (thrombectomy) is used primarily in low-risk surgical candidates who are not able to undergo thrombolysis. The best outcomes are achieved in individuals who receive surgical decompression and thrombolytics. Up to 75% of individuals who receive anticoagulants may have some residual disability and for 12% this may be severe (Maxwell-Armstrong).

Source: Medical Disability Advisor



ACOEM

ACOEM's Practice Guidelines, the gold standard in effective medical treatment of occupational injuries and illnesses, are provided in this section to complement the disability duration guidelines.*
 
Shoulder Disorders
 
* The relationship between the MDGuidelines (MDA) content and ACOEM's guidelines is approximate and does not always link identical diagnoses. The user should consult the diagnostic codes in both guidelines, as well as the clinical descriptions, before assuming an equivalence.

Source: ACOEM Practice Guidelines



Prognosis

From 40% to 80% of individuals with neurogenic TOS experience some relief of symptoms after surgery to relieve pressure on the brachial plexus and subclavian artery and vein, but approximately 10% to 15% of individuals experience recurrence of symptoms over time (Maxwell-Armstrong). Relief of pain symptoms usually is successfully achieved with nonsteroidal anti-inflammatory drugs (NSAIDS) or muscle relaxants. Individuals with arterial or venous TOS have much better outcomes if the initial diagnosis was correct.

Source: Medical Disability Advisor



Rehabilitation

The goal of rehabilitation of thoracic outlet syndrome is to decrease abnormal sensations, such as numbness and pain in the upper extremity, as well as to restore function of the affected shoulder girdle (Parziale). The therapist works closely with the individual to identify physical activities and postures that aggravate the condition and instructs in ways to avoid or modify these. Modalities such as local cold or hot packs may help to decrease symptoms (Braddom). Function may be restored by correction of abnormal posture or muscle imbalance of the shoulder girdle (Novak). These findings are best addressed by a specific stretching and strengthening program of the neck and shoulder girdle.

Most cases are managed conservatively; however when surgery is indicated rehabilitation is based on the surgeon's protocol and the type of surgery performed, for example scalenectomy versus resection of the rib (Abe; Mackinnon).

FREQUENCY OF REHABILITATION VISITS
Nonsurgical
SpecialistThoracic Outlet Syndrome
Occupational or Physical TherapistUp to 16 visits within 8 weeks
Surgical (rib resection)
SpecialistThoracic Outlet Syndrome
Occupational or Physical TherapistUp to 8 visits within 4 weeks
Surgical (scalenectomy)
SpecialistThoracic Outlet Syndrome
Occupational or Physical TherapistUp to 8 visits within 4 weeks
The table above represents a range of the usual acceptable number of visits for uncomplicated cases. It provides a framework based on the duration of tissue healing time and standard clinical practice.

Source: Medical Disability Advisor



Complications

Individuals with arterial TOS may have migration of blood clots from the artery at the shoulder and to the hand. Rarely, prolonged pressure on the nerves of the brachial plexus can cause atrophy of the muscles that it innervates. Complications from surgery include damage to nerves (long thoracic, phrenic, sympathetic nerves), leaks from the lymphatic system, hemorrhage, infection, and collapsed lung (pneumothorax).

Source: Medical Disability Advisor



Ability to Work (Return to Work Considerations)

Physical activities that must be altered or avoided include heavy lifting, direct load bearing on the shoulder, and working with arms and hands above shoulder height. In addition, ergonomically correct chairs, computer stations, and workstations can help reduce awkward postural positions as well as repetitive work activities that may have contributed to development of initial symptoms.

Source: Medical Disability Advisor



Failure to Recover

If an individual fails to recover within the expected maximum duration period, the reader may wish to consider the following questions to better understand the specifics of an individual's medical case.

Regarding diagnosis:

  • Does individual have a cervical rib?
  • Is there pain in the shoulder, arm, or hand? In the fourth or fifth fingers? Is pain aggravated by use of the arm?
  • Is there any muscle weakness or atrophy?
  • Is area above the clavicle tender? Is pulsation present?
  • Are symptoms reproduced when elevating the arm or exercising it? Is the radial pulse reduced or absent with arm elevation? Do the fingers become cyanotic?
  • Were x-rays of the cervical spine done? Nerve conduction studies? Has individual had brachial artery angiography? Venography? Doppler ultrasonography?
  • Have conditions with similar symptoms been ruled out?

Regarding treatment:

  • Does individual take part in an exercise program? Physical therapy? Use a shoulder brace?
  • Has individual changed work habits, if necessary?
  • Are physical activities that aggravate the condition being avoided?
  • Have NSAIDs or muscle relaxants been given?
  • Is surgery recommended? Has individual obtained a second surgical opinion?

Regarding prognosis:

  • Is individual active in physical therapy? Is a home exercise program in place?
  • Has individual made the necessary adjustments in physical activities to reduce symptoms?
  • Can individual's employer accommodate any necessary restrictions?
  • Does individual have any conditions that could affect ability to recover?
  • Did any blood clots develop in the artery at the shoulder?

Source: Medical Disability Advisor



References

Cited

Abe, M., K. Ichinohe, and J. Nishida. "Diagnosis, Treatment, and Complications of Thoracic Outlet Syndrome." Journal of Orthopaedic Science 4 1 (1999): 66-69. National Center for Biotechnology Information. National Library of Medicine. 25 Sep. 2008 <PMID: 9914431>.

Braddom, Randolph L. Physical Medicine and Rehabilitation. 3rd ed. Philadelphia: W.B. Saunders, 2006.

Chang, A. K., and Stephen J. Bohan. "Thoracic Outlet Syndrome." eMedicine. Eds. Richard S. Krause, et al. 4 Feb. 2008. Medscape. 29 Dec. 2008 <http://emedicine.com/emerg/topic578.htm>.

Mackinnon, S. E., and C. B. Novak. "Thoracic Outlet Syndrome." Current Problems in Surgery 39 11 (2002): 1070-1145. National Center for Biotechnology Information. National Library of Medicine. 25 Sep. 2008 <PMID: 12407366>.

Maxwell-Armstrong, C. A., et al. "Long-term Results of Surgical Decompression of Thoracic Outlet Compression Syndrome." Journal of the Royal College of Surgeons of Edinburgh 46 (2001): 35-38.

Novak, C. B. "Thoracic Outlet Syndrome." Clinics in Plastic Surgery 30 2 (2003): 175-188. National Center for Biotechnology Information. National Library of Medicine. 25 Sep. 2008 <PMID: 12737351>.

Parziale, J. R., et al. "Thoracic Outlet Syndrome." American Journal of Orthopedics 29 5 (2000): 353-360. National Center for Biotechnology Information. National Library of Medicine. 25 Sep. 2008 <PMID: 10868435>.

Povlsen, B., et al. "Treatment for Thoracic Outlet Syndrome (Protocol)." Cochrane Database of Systematic Reviews 3 (2008): NA.

Sanders, R. J., and S. L. Hammond. "Management of Cervical Ribs and Anomalous First Ribs Causing Neurogenic Thoracic Outlet Syndrome." Journal of Vascular Surgery 36 1 (2002): 51-56. National Center for Biotechnology Information. National Library of Medicine. 29 Dec. 2008 <PMID: 12096257>.

Sucher, B. M. "Thoracic Outlet Syndrome." eMedicine. Eds. Robert E. Windsor, et al. 13 Dec. 2006. Medscape. 29 Dec. 2008 <http://emedicine.com/pmr/topic136.htm>.

Source: Medical Disability Advisor






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