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Musculoskeletal disorders are common, affect all age groups, and are associated with a great deal of disability, impairment, and handicap. More than 12 million people in the United States have their activity limited by musculoskeletal disorders, a figure greater than for any other disease category (Fig. 66-1).1 Musculoskeletal impairments affect about 14% of the population, with the spine most commonly involved, followed by the lower extremity or hip and the upper extremity or shoulder (Table 66-1).2 Each year about 11% of the population in the United States experience a musculoskeletal injury severe enough that medical care is sought or activity is restricted for at least half a day.2 The total economic cost to the United States of musculoskeletal conditions was estimated to be $284 billion in 2000,3 second only to diseases of the circulatory system. Indirect costs from lost earnings and services represent a particularly high proportion of this cost, since many people are affected during their most productive years.
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DISORDERS PRIMARILY OF ADULTS
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Low Back and Neck Pain
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From 75 to 85% of people experience low back pain at some time during their lives.4 Most episodes of low back pain improve within a few weeks, but recurrences are common, and low back pain often becomes a chronic problem with intermittent, usually mild, exacerbations.5 In a study of English patients seen by general practitioners for low back pain, after one year only 25% had no pain or disability, even though the majority were no longer seeking care from their practitioner for their problem.6 In a small proportion of cases the pain becomes constant and severe, and such cases account for a high proportion of the cost; one study found that 25% of the cases accounted for 90% of the costs.7
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The specific lesion responsible for low back pain usually is not known. It is likely ...