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.

Spinal Stenosis


Related Terms

  • Cervical Stenosis
  • Lumbar Stenosis
  • Narrowing of Spinal Canal

Differential Diagnosis

Specialists

  • Neurologist
  • Neurosurgeon
  • Orthopedic (Orthopaedic) Surgeon
  • Physiatrist (Physical Medicine and Rehabilitation Specialist)
  • Physical Therapist

Comorbid Conditions

Factors Influencing Duration

The severity of pain, the severity of the neurologic deficit, comorbid vascular disease, the individual's age and overall health, and the type and success of treatment will influence the length of disability. Once severe spinal stenosis with neurologic deficit becomes evident, the individual is rarely capable of heavy or very heavy work. Following lumbar spinal stenosis decompression surgery, heavy and very heavy work are usually no longer appropriate.

Medical Codes

ICD-9-CM:
723.0 - Spinal Stenosis In Cervical Region
724.00 - Spinal Stenosis, Other than Cervical, Unspecified Region
724.02 - Spinal Stenosis, Other than Cervical, Lumbar Region, without neurogenic claudication; Lumbar region NOS
724.09 - Spinal Stenosis, Other than Cervical, Other
724.9 - Other Unspecified Back Disorders; Ankylosis of Spine NOS; Compression of Spinal Nerve Root NEC; Spinal Disorder NOS

Overview

Spinal stenosis is a narrowing of the spinal canal, the passageway in the spinal column, made of stacked vertebrae, through which the spinal cord and nerves pass. Spinal stenosis primarily occurs in the low back (lumbar spine) but may also occur in the middle back (thoracic spine) and the neck (cervical spine).

Stenosis is classified as primary or secondary stenosis. Primary stenosis, which is also called congenital stenosis, is a developmental abnormality that results in narrowing of the canal. It is usually diagnosed in younger individuals who develop symptoms of stenosis. Secondary stenosis is a degenerative condition associated with changes in the spine that occur as part of the natural aging process. Changes may include bone spur or osteophyte formation, facet hypertrophy, bulging discs, and ligamentous hypertrophy. Secondary stenosis can also occur as a result of back surgery or trauma (acquired stenosis). Secondary stenosis is the most common type of spinal stenosis.

Individuals may also have a combined form in which primary stenosis is worsened by the development of secondary stenosis. The combined form occurs in individuals who are born with narrow spinal canals, which undergo further narrowing as a result of degenerative or postoperative changes.

In lumbar stenosis, narrowing of the spinal canal compresses the neural elements and reduces the blood supply to the nerves that supply sensation and motor control to the legs. Individuals most commonly present with complaints of fatigue or heaviness in their legs that occurs with walking and is relieved by sitting. In severe cases, even the nerves controlling bowel and bladder emptying may be affected. There are three places where the spinal nerves might be compressed, and the stenosis may be described by location: in the central canal of the spinal column (central stenosis), as the nerves leave the spinal column (foraminal stenosis), or just after the nerve has left the canal (lateral stenosis). Foraminal stenosis is the most common and typically affects the roots that comprise the sciatic nerve.

Incidence and Prevalence: Five in 1,000 individuals over age 50, or about 250,000 to 500,000 individuals in the US, have symptoms of spinal stenosis (Hsaing). Because most individuals with mild spinal stenosis have no symptoms, the incidence can only be approximated. Symptoms do not occur until narrowing of the spinal canal has progressed enough to impinge on the nerve root(s) or the spinal cord. Seventy-five percent of spinal stenosis cases occur in the lumbar spine (Ray). Because the US population is aging, prevalence is expected to increase, growing by 18 million within the next decade (Hsaing).

Source: Medical Disability Advisor



Causation and Known Risk Factors

The average age of onset of symptoms of degenerative stenosis is 60 years, and men are afflicted twice as often as women. Primary or congenital stenosis may present by 30 years of age, and the risk of symptoms increases with age because of superimposed degenerative changes associated with aging. Individuals with osteoarthritis, rheumatoid arthritis, scoliosis, spondylolisthesis, achondroplastic dwarfism, and Paget's disease are at an increased risk of developing spinal stenosis.

Source: Medical Disability Advisor



Diagnosis

History: The cardinal symptoms of spinal stenosis are numbness and pain. In lumbar stenosis, individuals also report lower back pain, radiating leg pain, and an intolerance for walking. The individual typically describes pain in the calf, buttocks, or back of the thigh when walking (neurogenic claudication) or standing. Pain, which frequently affects both legs (bilateral), is commonly characterized as aching but may also present as numbness or weakness. The pain is often sufficiently intense to force individuals to stop walking and to sit in order to seek relief. Others may report greater comfort walking uphill than downhill or that they can walk farther while bending forward. Depending on severity, individuals may also describe sensations of hot or cold, tingling, leg fatigue, and dysfunction of the bladder or bowel associated with lumbar stenosis. A complete health history is obtained, including current and prior illnesses and a history of injuries.

Physical exam: Having the individual arch the back to extend the spine may reproduce or worsen the symptoms. Flexing the spine (e.g., sitting, bending over) typically reduces the symptoms. Generally, except in cases of severe stenosis, physical examination will be unremarkable for neurologic findings. Raising the leg while it is straightened may cause pain. Leg deep tendon reflexes may be depressed. A general physical exam may be conducted to assess health status, especially signs and symptoms of chronic illness.

Tests: Imaging studies are absolutely necessary to establish a diagnosis. Either MRI or CT myelogram can accurately show the degree and extent of stenosis. MRI is preferred because CT myelogram is invasive, even though it provides better delineation of bony anatomy and nerve root involvement. A plain lumbar x-ray will not conclusively show spinal stenosis, though severe degenerative changes may be suggestive.

Source: Medical Disability Advisor



Treatment

Conservative, nonsurgical treatment using analgesics, spinal (epidural) or oral steroids, physical therapy (aerobic conditioning, muscle strengthening, flexibility enhancement, and optimization of body mechanics), and bracing may provide symptom relief in milder cases without neurological symptoms. Cervical traction may provide relief of radicular pain stemming from nerve root compression in the cervical spine but will not relieve the pain of soft tissue injury. A soft cervical collar may provide short-term relief of soft-tissue injury; for radiculopathy caused by foraminal stenosis, the collar is placed in a manner that allows neck flexion and extension and to open the intervertebral foramina. Only decompressive surgery can actually enlarge the spinal canal of the lumbar and cervical spine. If signs and symptoms of myelopathy, segmental instability, or cauda equina syndrome (nerve compression affecting bladder and bowel function) are present, emergency surgical decompression of the spinal cord or nerve roots is indicated. Surgery is also indicated for individuals with moderate to severe symptoms that are not relieved by conservative measures and time.

The goals of surgery are to reduce pain, decompress affected nerves, provide more room for the spinal cord, and restore spinal stability. The method of surgical decompression employed depends on the location, cause, type, and severity of spinal stenosis; the age and overall condition of the individual; and the preference of the surgeon. If a sufficient portion of the joint is removed or the individual has advanced degenerative disease, then it may also become necessary to perform arthrodesis (with or without stabilizing internal fixation) to stabilize the spine.

Lumbar decompressive surgery, which may consist of one or more procedures, is performed through an incision in the back. Most frequently, the lamina of a vertebra are removed (laminectomy), often at multiple levels. Other surgical options include removal of bone from around a nerve root (foraminotomy), removal of an intervertebral disc (discectomy), and/or fusion of two or more vertebrae (arthrodesis).

Cervical spine surgery may consist of foraminotomy to open the foramen and decompress the affected nerve; laminotomy to create a hole in the lamina and reduce pressure on the spinal cord; laminectomy, which removes part or all of the lamina to reduce pressure on the cord; or laminoplasty, which reshapes the lamina surgically, creating more room for the spinal cord. Cervical procedures can be performed from the front (anterior) of the spine or at the back of the neck (posterior). Cervical stenosis is frequently the result of anterior compression due to osteophyte formation, requiring the more difficult anterior surgical approach, which also involves higher risk and may require fusion. Fusion is not indicated for patients with poor health status or reduced bone density.

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.*
 
Low Back Disorders
Neck and Upper Back 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

Spinal stenosis often runs a gradual course, and it may be stable and asymptomatic or minimally symptomatic for several years. Conservative treatment is effective in reducing pain for half of affected individuals, provided their symptoms are mild to moderate. Surgical decompression usually succeeds in improving or eliminating leg pain and improving the individual's ability to walk but does not stop the degenerative process, and the symptoms may recur. In lumbar stenosis, symptoms may recur about 4 to 5 years after the decompression surgery because the condition is progressive.

Source: Medical Disability Advisor



Rehabilitation

The focus of rehabilitation for spinal stenosis is to promote function and to teach individuals how to manage the symptoms independently. Spinal stenosis, a progressive condition, may be managed nonoperatively or operatively (Amundsen; Atlas).

Nonoperative: In conjunction with pharmacological management and local injections, heat and cold may be used to provide temporary relief of symptoms (Braddom). Gentle exercises that emphasize flexion of the trunk can be taught with careful supervision and attention to tolerance by the individual. General aerobic conditioning exercises should be taught, preferably walking on level surfaces, bicycling, or swimming.

Operative: Following the operation for spinal stenosis, the surgeon may prescribe therapy, with the specific type of therapy determined by the nature of the surgery (decompression alone, or with fusion, one level or multilevel). Most individuals undergoing surgery are older, and their rehabilitation must take into account the likelihood of comorbidity. Following surgery, some individuals may benefit from occupational therapy to assess the need for devices to promote independence in daily activities. Once indicated, exercise should proceed as for nonoperative treatment.

Individuals should be instructed in proper body mechanics and a home exercise program to complement the supervised rehabilitation. An ergonomic assessment may be beneficial to ensure that the work tasks do not unnecessarily stress the spine.

FREQUENCY OF REHABILITATION VISITS
Nonsurgical
SpecialistSpinal Stenosis
Physical TherapistUp to 15 visits within 6 weeks
Surgical
SpecialistSpinal Stenosis
Physical TherapistUp to 15 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

Secondary spinal stenosis is the result of degenerative changes in the spine and may be complicated by cauda equina syndrome, which is caused by compression of the nerves that go to the lower extremities, bowels, and bladder. Complications of surgical treatment may include wound infection, leakage of spinal fluid, or injury to neural structures. Spinal instability may be a long-term consequence of surgery. The anterior surgical approach used for cervical spinal stenosis has a greater risk of complications, including vascular injury, laryngeal nerve injury with vocal cord paralysis, esophageal injury and swallowing difficulties, instrumentation failure, and, since fusion is the most common procedure, failed fusion. If fusion is performed, the risk of nonunion is higher in long-term smokers and when multilevel fusion is done. The risk of complications is greater in patients with chronic disease or who have used steroids for long periods.

Source: Medical Disability Advisor



Ability to Work (Return to Work Considerations)

Mild and moderate spinal stenosis on imaging studies may be asymptomatic, and without evidence of neurologic impairment, there should be no restriction in work abilities. Work restrictions and special accommodations need to be established on an individual basis. Activities involving standing or walking may need to be limited. Work station modification to permit good posture or seated work may be helpful. Overhead work (spine extension) should be avoided. To reduce the risk of complications (e.g., nonunion of an arthrodesis), the individual who was treated surgically may not be allowed to work during the early recovery period. Use of analgesics and other medications can affect dexterity and alertness. Drug-testing policies will need to be evaluated.

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:

  • Has diagnosis of spinal stenosis been confirmed?
  • Is the stenosis shown on imaging mild or moderate and thus unlikely to explain the failure to work or function?
  • Is the stenosis shown on imaging severe, so that reduced activity tolerance correlates with severe pathology?
  • Has individual experienced any complications from the spinal stenosis, such as sciatica, claudication, intractable buttock and leg pain, or bladder or bowel dysfunction?
  • Does individual have an underlying or chronic condition that may affect recovery?

Regarding treatment:

  • Have conservative measures been effective? If not, is surgery indicated?
  • Was spinal fusion performed?
  • If surgery was unsuccessful in relieving leg pain, does a postoperative MRI or EMG document persisting nerve compression?
  • If individual has persistent back pain and/or leg pain after lumbar decompressive surgery do postoperative flexion extension x-rays document spinal instability?

Regarding prognosis:

  • Are symptoms and neurologic deficits severe enough to impair function?
  • If surgery was not successful in restoring function, what other treatment options are available to individual?

Source: Medical Disability Advisor



References

Cited

Amundsen, T., et al. "Lumbar Spinal Stenosis: Conservative or Surgical Management?: A Prospective 10-year Study." Spine 25 11 (2000): 1424-1435. National Center for Biotechnology Information. National Library of Medicine. 3 Mar. 2009 <PMID: 10828926>.

Atlas, S. J., et al. "Surgical and Nonsurgical Management of Sciatica Secondary to a Lumbar Disc Herniation: Five-Year Outcomes from the Maine Lumbar Spine Study." Spine 26 10 (2001): 1179-1187.

Atlas, S. J., et al. "Surgical and Nonsurgical Management of Sciatica Secondary to a Lumbar Disc Herniation: Five-Year Outcomes from the Maine Lumbar Spine Study." Spine 26 10 (2001): 1179-1187. National Center for Biotechnology Information. National Library of Medicine. 15 Dec. 2004 <PMID: 10749631>.

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

Hsiang, John. "Spinal Steonsis." eMedicine. Eds. Paul L. Penar, et al. 13 Dec. 2007. Medscape. 3 Mar. 2009 <www.emedicine.com/med/topic2889.htm>.

Ray, Charles Dean. "Spinal Stenosis Symptoms, Diagnosis and Treatment." Spine-health.com. 3 Apr. 2007. 3 Mar. 2009 <http://www.spine-health.com/conditions/spinal-stenosis/spinal-stenosis-treatment>.

Source: Medical Disability Advisor






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