Carpal tunnel syndrome: Epidemiology and risk factors

Carpal tunnel syndrome (CTS) is the most frequent mononeuropathy seen in the general population. Defined as median nerve compression at the level of the wrist, CTS causes numbness and tingling in the hand and fingers. The first introduction of the term "carpal tunnel syndrome" is attributed to Brain in 1947 and the popularization of its diagnosis and treatment to Phalen in 1950. Since then, there has been continued debate over the optimal management of this disease. CTS is the most expensive upper-extremity musculoskeletal disorder at an estimated cost of medical care in the US exceeding $2 billion annually, primarily due to surgical releases. The extra-medical costs are substantially greater. In fact, during 2006 in the US, surgeons performed 580,000 outpatient carpal tunnel releases [6] and the median lost worktime from work-related CTS is 27days, which is longer than any other work-related disorder except fractures. Although CTS is a strong driver of workers compensation costs, lost wages, lost productivity, and disability, there is still an incomplete understanding of its frequency and causes in working populations. Prevalent CTS in general populations range from 1-5% and among manufacturing and meat-packing workers has ranged from 5- 21%. Incidence rates from many studies on workers of CTS ranged from 1-15 per 1000 person-years and varied by industrial and occupational. In the general population, the emphasis on possibly risk factors is focused on demographic characteristics (female gender, older age) and on comorbid conditions (higher BMI, rheumatoid arthritis, diabetes mellitus and thyroid disease. Associations between CTS and other risk factors, such as gout, smoking status are uncertain as well as personal and workplace psychosocial possible involvement. However, general population studies do not take workplace exposures into account. The prevalence of CTS in working populations is generally higher than in the general population. Occupation-related CTS represents one of the major health problems among workers in various occupations throughout the world including Sweden, Italy, France, Japan, Taiwan. Recognized occupational risk factors are identify manual loadings with a significantly higher risk or association with CTS, comprise the use of handheld vibrating machinery, forceful gripping of objects with hands, repetitive and frequent manual tasks and forced postures of the wrist (flexion/extension). These loadings are usually combined during occupational work.