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.

Degeneration, Thoracic or Thoracolumbar Intervertebral Disc


Related Terms

  • DDD
  • Degenerative Disc Disease
  • Thoracic Intervertebral Disc Disease

Differential Diagnosis

Specialists

  • Anesthesiologist
  • Chiropractor
  • Orthopedic (Orthopaedic) Surgeon
  • Physiatrist (Physical Medicine and Rehabilitation Specialist)
  • Physical Therapist
  • Rheumatologist
  • Sports Medicine Physician

Comorbid Conditions

Factors Influencing Duration

The severity of the degeneration, number of discs affected, neurological involvement, treatment required, and response to treatment may affect disability. The presence of chronic illness or spinal deformity may increase duration. The ability to modify work requirements may also affect the disability period.

Medical Codes

ICD-9-CM:
722.51 - Thoracic or Thoracolumbar Disc Degeneration
722.72 - Thoracic Disc Disorder with Myelopathy

Overview

Degeneration of a thoracic disc describes the gradual, age related loss of mechanical properties of the intervertebral discs that separate and cushion the bones (vertebrae T1 through T12) of the thoracic spine in the mid and upper back. It most often affects the lower thoracic spine, between T9 and T12. Degeneration reduces the disc's normal ability to absorb physical impact and provide cushioning for the vertebral column. Degeneration of a thoracic disc is marked by a gradual narrowing of the disc space, placing stress on the other joints of the vertebrae (facet joints). The thoracic spine is least likely of all areas of the spine to develop chronic pain; symptoms are much less common than in the neck (cervical spine) or lower back (lumbar spine) because very little motion occurs in the thoracic spine compared to the neck and low back.

The development of thoracic disc degeneration (pathogenesis) is not well defined. As in the cervical and lumbar spines, thoracic disc degeneration is part of normal aging. Why some have back pain and others do not with equal degrees of disc degeneration and arthritic change is unknown. A history of trauma may be present in younger individuals who develop thoracic pain. Those with chronic spinal cord or nerve root compression frequently have prolonged symptoms, although MRI studies on asymptomatic people note that asymptomatic disc herniations are seen in up to one-third of these asymptomatic people. Wood (1995) found 71% of asymptomatic men and 48% of asymptomatic women over age 40 had degenerative changes on MRI, 37% of this group had actual asymptomatic disc herniations, and 29% had asymptomatic herniations that touched and deformed the spinal cord. In a follow up study (Wood 1997), 20 patients with 48 asymptomatic disc herniations were re-examined on average 26 months later, and none of the 20 had developed symptoms.

Intervertebral disc degeneration, especially in the lumbar spine, begins most commonly in people in their second decade of life (Kjaer). Whether the degenerating disc is a cause of back pain is controversial. Doctors who attribute back pain to degenerating discs frequently use the term "degenerative disc disease" (DDD). However, scientific evidence that the aging changes ("degeneration") seen on imaging are responsible for (correlate with) back pain is not present, and thus the term "non-specific back pain" is the more prevalent term used instead of degenerative disc disease. Intermittent episodes of back pain may occur months or years before more persistent thoracic back pain. Pain may be exacerbated by rotation of the spine (twisting), as rotation occurs mainly in the thoracic spine. It has been demonstrated that minor trauma does not cause either serious chronic low back pain and disability, or new MRI findings, but similar studies have not been done for thoracic pain (Carragee, "Minor Trauma"; Carragee, "First-time Episodes"). The rate at which individuals develop aging ("degenerative") change on imaging is largely genetically determined. Occupational and recreational exposure has very little effect on the rate of spinal aging (Battié).

Incidence and Prevalence: The incidence of thoracic disc degeneration increases with age and is believed to be high, but it is often asymptomatic and goes unreported. Most studies on the prevalence of thoracic pain are in children and adolescents. The systematic review by Briggs did find that prevalence increases with age until about age 50. The decrease after age 50 may be due to osteoporosis becoming more common after age 50 and thus pain after age 50 being attributed to osteoporosis, and not to “degenerative discs.”

Symptomatic thoracic disc herniations are extremely rare, occurring in one in 1 million individuals annually and accounting for only 0.25% to 0.75% of all symptomatic disc herniations (Canale). Thoracic disc herniation represents 0.13% to 0.15% of all hospital admissions for disc disease in most institutions (Manges).

Source: Medical Disability Advisor



Causation and Known Risk Factors

Aging is the most significant risk factor for thoracic disc degeneration due to normal age-related changes in disc integrity. As in the lumbar spine, genetics is probably the main risk factor for premature disc degeneration. In the elderly, the presence of chronic disease such as osteoporosis and osteoarthritis increases the risk of pain in the thoracic spine. Thoracic herniated discs occur equally often in men and women (Manges).

Source: Medical Disability Advisor



Diagnosis

History: Individuals may complain of mid and/or upper back (thoracic) pain or a decrease in sensation. The pain may radiate along the course of a rib to the anterior chest or abdomen, but thoracic discs do not typically refer pain to the lower limbs. A complete health history should be taken, including prior and current illnesses and injuries. Diseases of the heart, aorta, esophagus, and lung may have back pain as a symptom, so other symptoms of those non-musculoskeletal organs should be sought.

Physical exam: The physician will put pressure on (palpate) the spine, which may cause tenderness over the affected area. Thoracic motion decreases with age, as do degenerative disc changes, so in those old enough to have degenerative changes there is usually decreased thoracic motion on exam. Physicians however rarely record thoracic motion measurements. Physical exam thus serves to evaluate for other problems, and is typically not helpful in diagnosing non-specific thoracic pain, attributed by some physicians to degenerative thoracic discs.

Among the other problems are thoracic disc herniations (a different diagnosis), which can cause loss of sensation in the dermatome of a single thoracic nerve root, but there is no reflex or muscle strength to examine and to potentially correlate with a thoracic disc herniation with nerve root compression. If a herniation causes spinal cord compression, there may be weakness or incoordination in the lower limbs or incontinence. Gait and posture can be affected by disc herniation that causes spinal cord compression and are usually evaluated during the physical exam.

Another problem may be an increased curve to the low back when the person is viewed from the side (kyphosis), suggesting Scheuermann’s disease in young adults or osteoporotic compression fractures in old adults.

Tests: Plain x-rays may show calcification of a thoracic disc. Other degenerative changes such as bony outgrowths (osteophytes) or disc space narrowing may also be present. In addition to degenerative changes, x-rays may show scoliosis or kyphosis. If mechanical instability is suspected as a cause of recurrent pain, it can be documented by x-rays taken with the spine bent forward (flexion) and then backward (extension). Instability of the thoracic spine is extremely rare, because the ribs provide stability.

CT scanning may be useful to rule out other spinal disorders such as fracture, tumor, or infection; however, in the thoracic region, CT cannot reliably rule out displacement (herniation) of thoracic intervertebral discs unless it is done in combination with CT myelography. MRI can usually rule out disc displacement as well as many other spinal disorders. A further advantage of MRI is that it can distinguish between a degenerated non-herniated disc and a herniated one. Since disc degeneration is part of the universal aging process and usually occurs without symptoms, a degenerated disc seen on an MRI scan must be closely correlated with symptoms and physical examination.

Radiography of the spine after injecting an absorbable contrast medium into the disc (discography) is another method of distinguishing between a degenerated and a normal disc. However, thoracic discography is technically difficult to do and is much less useful in evaluating the thoracic spine than the cervical or lumbar spine. Most discs in the thoracic spine have at least some pain on injection and some abnormality on discography images, making interpretation of discography findings very challenging (Wood 1999).

Source: Medical Disability Advisor



Treatment

The goal of conservative treatment is to relieve pain and restore mobility. When symptoms are acute, short-term rest and immobilization of the spine may be recommended, but activity is encouraged as soon as pain permits. If the individual is up and about, a back brace may be used. For relief of pain, nonsteroidal anti-inflammatory drugs (NSAIDs) may be given. If pain is severe, a narcotic may be added. If the pain is chronic and if anxiety and tension are prominent, antidepressants may be helpful. Muscle relaxants are frequently prescribed, but their effectiveness comes from their sedative action. Narcotics, sedatives, and muscle relaxants are usually used only for brief periods of time. Ongoing use should be weighed against the potential for abuse. Other treatments, such as ice, heat, massage, and ultrasound therapy, may help relieve pain. Spinal manipulation is often performed and may be effective for some individuals.

As symptoms subside, activity is gradually increased and may include a home exercise program. Preventive and maintenance measures such as exercise and correct body mechanics should be continued indefinitely.

Surgery is performed only to correct a herniated disc. Indications for surgery include frank disc herniation with enough spinal cord compression to cause persistent neurological deficit. For such cases, discectomy with or without segmental spinal fusion may be performed.

Source: Medical Disability Advisor



Prognosis

Thoracic disc degeneration is chronic and irreversible aging change, and like gray hair in a mirror, the changes on imaging increase with age. Acute episodes of pain and weakness may be self-limiting, not exceeding a few weeks. The outcome depends on the activity level of the individual and adherence to recommendations for exercise and maintenance of normal activity. In the thoracic spine there is much less evidence that psychosocial factors predict outcome (chronicity) compared to non-specific cervical spine and lumbar spine pain. The prognosis for relief of symptoms with conservative treatment is good for most individuals. The presence of chronic illness, such as osteoporosis or osteoarthritis, or pre-existing spinal deformity, may accelerate or complicate disc degeneration.

Source: Medical Disability Advisor



Rehabilitation

Individuals with pain and with imaging showing degeneration of thoracic intervertebral discs may benefit from rehabilitation to decrease pain as well as to regain mobility and strength in that particular region of the spine.

Acute Phase: Therapy to reduce symptoms, followed by spinal exercises, may be all that is required for mild cases. However, more involved rehabilitation is required for severe symptoms. Passive intervention should be time limited, with emphasis on active exercise. Exercises and education should focus on postural alignment and on directing individuals to stay active (Malmivaara; McNeely; Bigos).

Sub Acute Phase: Instruction should be given on an exercise program that will help maintain the individual's well-being. By this time modalities should not be necessary, and continued use of such passive therapy is usually counterproductive. During this phase, the workplace may undergo an ergonomic evaluation, followed by necessary changes to assist the employee in continuing at or returning to work. Toward the later stages of this phase, if the individual fails to progress or progresses too slowly, a health psychologist may evaluate the individual to determine whether or not there are signs of psychological distress. There is evidence that a multidisciplinary treatment approach can be effective in treating these individuals.

Chronic Phase: Exercise instruction must continue. The program should combine coordination, aerobic conditioning, and flexibility, educating the individual on functional exercises and proper body mechanics. A short course on cognitive pain management may be beneficial. If not yet done, an ergonomic evaluation with modifications may enable the individual's return to work and reduce the risk of pain flare-up upon return to work. Vocational services should be available for individuals who cannot return to their previous job title or do not have a job to which to return.

For further information about management of this condition and rehabilitation outcome, please refer to "Surgery for Degenerative Lumbar Spondylosis" (Gibson).

FREQUENCY OF REHABILITATION VISITS
Nonsurgical
SpecialistDegeneration, Thoracic or Thoracolumbar Intervertebral Disc
Physical TherapistUp to 12 visits within 6 weeks
Surgical
SpecialistDegeneration, Thoracic or Thoracolumbar Intervertebral Disc
Physical TherapistUp to 6 visits within 6 weeks
Note on Surgical Guidelines: Rehab usually begins after tissue healing, about 6 to 8 weeks after surgery.
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

The condition may very, very rarely progress to a symptomatic thoracic disc herniation. Narrowing of the spinal canal (spinal stenosis) is another rare but possible complication, but it is not as common as in the lumbar and cervical regions.

Source: Medical Disability Advisor



Ability to Work (Return to Work Considerations)

Temporary work restrictions may include avoidance of prolonged standing or sitting, lifting, carrying, bending, twisting, and activities that involve heavy vibration (such as driving large earth moving vehicles and using construction equipment such as jackhammers). Individuals may benefit from brief rest periods or an opportunity to walk. Use of pain medication and muscle relaxants can affect dexterity and alertness. Safety issues will need to be evaluated. Work-hardening programs and worksite evaluations are beneficial to many individuals and may allow for earlier return from disability.

Source: Medical Disability Advisor



Maximum Medical Improvement

By definition “degenerative disc disease” (aging change) occurs over long time periods and this is not an acute injury. However, in workers’ compensation, workers will allege their pain begins during a work activity, and physicians who use this diagnosis will state the work activity “aggravated the degenerative changes.” There is no scientific way to prove or disprove this claim, so the diagnosis of work-aggravated-degenerative-disc disease is at times in the workers’ compensation system. By 4 months after pain onset, the condition is unlikely to change, absent surgical treatment. Thus MMI can be established usually by 4 months after the “aggravating incident.”

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:

  • Was a diagnosis of degeneration of thoracic or thoracolumbar intervertebral disc confirmed through x-ray or MRI?
  • Did MRI rule out conditions such as spinal infection, tumor, fracture, and disc herniation? Are chronic conditions present instead, such as osteoporosis or osteoarthritis?

Regarding treatment:

  • Did symptoms respond to treatment?
  • Is the individual using of narcotics, sedatives, and/or muscle relaxants that have sedation or cognitive impairment as side effects? Does use of these medications conflict with the employer’s policy for safety sensitive positions?
  • Was bracing employed?
  • Was individual compliant with exercise program in therapy, and is the individual doing a home exercise program?
  • Was spinal manipulation performed?

Regarding prognosis:

  • Did the individual participate in a rehabilitation program? Was the individual compliant with therapy?
  • To what extent does pain affect the individual’s willingness to function? What workplace modifications could occur to encourage return to work?
  • Does individual have an underlying condition that may affect recovery?

Source: Medical Disability Advisor



References

Cited

Battié, M. C. , et al. "The Twin Spine Study: Contributions to a changing view of disc degeneration." Spine 9 (2009): 47-59.

Bigos, S., et al. "Acute Low Back Problems in Adults." Clinical Practice Guidelines No 14. AHCPR Publication No. 95-0642. Rockville, MD: Agency for Healthcare Policy Research (AHCPR), 1994.

Canale, S. Terry, and James H. Beaty, eds. "Thoracic Disc Disease." Campbell's Operative Orthopaedics. 11th ed. Philadelphia: Mosby Elsevier, 2008. 2195-2197.

Carragee, E., et al. "Are First-time Episodes of Serious Low Back Pain Illness Associated with New MRI Findings?" Spine 6 6 (2006): 624-635.

Carragee, E., et al. "Does Minor Trauma Cause Serious Low Back Pain Illness?" Spine 31 25 (2006): 2942-2949.

Gibson, J. N., G. Waddell, and I. C. Grant. "Surgery for Degenerative Lumbar Spondylosis." Cochrane Database of Systematic Reviews 3 (2000): CD001352. National Center for Biotechnology Information. National Library of Medicine. 15 Nov. 2004 <PMID: 10908493>.

Gross, D. P. , and M. C. Battié. "Functional Capacity Evaluation Performance Does Not Predict Sustained Return to Work in Claimants with Chronic Back Pain." Journal of Occupational Rehabilitation 15 (3) (2005): 285-294.

Hall, H. , et al. "Effect of Discharge Recommendations on Outcome." Spine 19 (18) (1994): 2033-2037.

Kjaer, P. , et al. "An Epidemiologic Study of MRI and Low Back Pain in 13-Year Old Children." Spine 30 (7) (2005): 798-806.

Malmivaara, A., et al. "The Treatment of Acute Low Back Pain--Bed Rest, Exercises, or Ordinary Activity?" New England Journal of Medicine 332 6 (1995): 351-355. National Center for Biotechnology Information. National Library of Medicine. 15 Nov. 2004 <PMID: 7823996>.

Manges, Pamela A. "Video-Assisted Thoracoscopic Discectomy and Fusion." AORN 67 5 (1998): 940-950.

McNeely, M. L., G. Torrance, and David J. Magee. "A Systematic Review of Physiotherapy for Spondylolysis and Spondylolisthesis." Manual Therapy 8 2 (2003): 80-91. National Center for Biotechnology Information. National Library of Medicine. 15 Nov. 2004 <PMID: 12890435>.

Wood, K. B. , et al. "The natural history of asymptomatic thoracic disc herniations." Spine 22 (1997): 525-530.

Wood, K. B. , et al. "Thoracic Discography in Health Individuals." Spine 24 (15) (1999): 1548-1555.

General

Wood, K. B., et al. "Magnetic Resonance Imaging of the thoracic Spine." Journal of Bone and Joint Surgery 77-A 11 (1995): 1631-1638.

Source: Medical Disability Advisor






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