Cumulative trauma disorders injuries

Every year, about 19 million American workers are disabled by musculoskeletal injuries at a cost of about 100 billion. Over one third of all workers compensation costs are associated with cumulative trauma disorders, injuries caused by trauma to the body occurring over a period of time. 

Armstrong, T. J., and Lifshitz, Y. (1987), Evaluation and Design of Jobs for Control of Cumulative Trauma Disorders, in Ergonomic Interventions to Prevent Musculoskeletal Injuries in Industry, American Conference of Governmental Industried Hygienists, Lewis, Chelsea, MI. 

Human factors are also important in rehabilitation, where various aids for the disabled must be sized correctly, be versatile enough to accommodate special needs, be acceptable to the human user, and be socially acceptable to others. Without proper incorporation of human factors, health problems such as eyestrain, mental stress, and physical injury can result. Cumulative trauma disorder (work-related musculoskeletal disorder) comes about when working repetitively with tools under awkward conditions. Carpel tunnel syndrome is one form of this. 

For many incidents resulting in back injuries, strains and sprains, cumulative trauma disorders, and others, employees were adhering to the prescribed work procedure when the incident occurred. Typically, an incident investigation report would show that an unsafe act, a human error, was the principal incident cause. 

A work-related musculoskeletal disorder is an injury to the muscles, tendons, and/ or nerves of the upper body either caused or aggravated by work. Other names used to describe work-related musculoskeletal disorders include repetitive motion injuries, repetitive strain injuries, cumulative trauma disorders, soft tissue disorders, and overuse syndromes. Work-related musculoskeletal injuries (MSIs) affecting the upper body and limbs are now recognized as one of the leading causes of worker pain and disability. 

In 1981, cumulative trauma disorders (CTDs) made up about 18 percent of the occupational injuries and illnesses reported to OSHA. 

Repeated motion by users operating a tool or machine can lead to a group of injuries called cumulative trauma disorders or repeated motion disorders (RMDs). 

Cumulative trauma injuries, cumulative trauma disorders or repeated motion injuries are a family of injuries that result from repeated motion or repeated use of a tool or other equipment. Most involve inflammation of or damage to various tissues. Several may occur at the same time. The appearance of symptoms will vary from person to person, with frequency of activity, forces, and movements involved in the activity, and other factors. Factors other than repeated motion, such as age and personal differences, may contribute to the incidence of these disorders. 

Cumulative trauma disorders (CTDs), also referred to as repetitive-motion injuries, result from excessive use of the hand, wrist, or forearm. As with overexertion injuries, the frequency and costs of CTDs are growing to epidemic proportions. Some of the most common cumulative trauma disorders are carpal tunnel syndrome, cubital tunnel syndrome, tendinitis, and tenosynovitis. 

Most of the safety and health community considers back injuries a one-time event. It seems more realistic to consider such iiguries as caused by a series of microtraumas (strains and sprains) over time that eventually results in what is commonly called a back injury. This concept moves back injuries into the realm of cumulative trauma disorders. Many companies in the past hired younger workers who may be less susceptible to injury to do continuous or repetitive lifting task rather than use older or more experienced woikers who might be more likely to be injured. These young workers had not had the micro-trauma mjuries that set than up for a back injury. 

Some ergonomically designed keyboards are available with a rest-time indicator, which encourages the user to take a break from the computer. Although laptop computers are portable and convenient, work-related musculoskeletal injuries can still occur if one does not observe proper ergonomic principles while using a laptop. Cumulative trauma disorders, caused by repetitive strain or motion injuries and work-related musculoskeletal disorders, are the largest cause of occupational disease in the United States. 

Injury results either more or less instantaneousfy when the strain of muscles, tendons or ligaments carmot match the stress or load apphed, and these tissues are stretched or tom. Injirty can also result from repeated lower level overloading, i.e. cumulative trauma disorder - CTD. Note that the word strain or sprain is also applied to the injury. 

The first studies were described in occupational cervicobrachial disorder in cash register operators, driller s card and Japanese typists in Australia, described occupational overuse injury in typists and workers of the assembly line cases were subsequently referred to cumulative trauma disorders in workers exposed to cumulative trauma, including operators of video display terminals in the United States of America (McDermott, 1986, Kiesler and Finholt, 1988). 

When the word ergonomics is mentioned most employers and many others will tend to make derogatory comments and act as thongh ergonomics is some kind of contrived problem. However, from my experience of visiting many types of industries and workplaces, it is not at all unusual for me to talk to a person who has had live surgeries related to musculoskeletal disorders (MSDs), cumulative trauma disorders (CTDs), or repetitive motion injuries (RMls). In this chapter these terms will be used interchangeably. 

Vibrating tools and equipment at frequencies between 40 and 90 hertz can cause damage to the circulatory and nervous systems. Care must be taken with low frequencies, which have the potential to put workers at risk for vibration injuries. One of the most common cumulative trauma disorders (CTDs) resulting from vibration is Raynaud s Syndrome. Its most common symptoms are intermittent numbness and... 

One of the authors was involved in a project with an ergonomist to find control methods for cumulative trauma disorders, i.e., muscle strains, stress, back injuries, etc. 

The focus of ergonomics is on the work environment and includes factors such as design of workstations, controls, displays, safety devices, tools, and lighting to fit the employees physical requirements and to ensure their health and well-being. Many times a restructuring of the work environment helps to reduce the stressors that cause cumulative trauma disorders (CTDs) and repetitive motion injuries (RMIs). 

There were many nonspecific illnesses, or syndromes, that emerged in the late twentieth century. Despite, or perhaps because of, their proliferation, they are usually controversial. All have in common either a lack of identifiable cause or a diversity of expression, or both. In addition to sick building syndrome and multiple chemical sensitivity, nonspecific Ulnesses include Gulf War syndrome, chronic fatigue syndrome, acquired immunodeficiency syndrome, cumulative trauma disorder (also called repetitive strain injury), and a host of psychological disorders. 

The National Institute of Occupational Safety and Health (NIOSH 1997) states that musculoskeletal disorders, which include disorders of the back, trunk, upper extremity, neck, and lower extremity are one of the 10 leading work-related illnesses and injuries in the United States. Praemer et al, (1992) report that work-related upper-extremity disorders (WUEDs), which are formally defined by the Biureau of Labor Statistics (BLS) as cumulative trauma illnesses, account for 11.0 % of aU work-related musculoskeletal disorders (illnesses). For comparison, occupational low-back disorders account for more than 51.0% of aU WRMDs. According to BLS (1995), the cumulative trauma illnesses of upper extremity accounted for more than 60% of the occupational illnesses reported in 1993. These work-related illnesses, which include hearing impairments due to occupational noise exposure, represent 6.0% of aU reportable work-related injuries and illnesses (Marras 1996). 

D. BACK INJURY PREVENTION. While most back disorders result from cumulative trauma or gradual insult to the back over time, some injuries are caused by a sudden excessive load or fall. These disorders are by far the largest single category of all lost-time injuries, and have enormous financial implications. 

Accident and Injury As noted in Chapter 3, the term accident suggests an event of very short duration. This was the meaning for early interpretations under workers compensation claims. For most workers compensation laws today, accident may refer to extended exposures and recognize other factors. In the early 1980s, claims increased significantly for cumulative trauma injuries. These disorders result from repeated trauma to the part of the body affected, such as the arm of a carpenter swinging a hammer. More recently, claims for various forms of job stress have been on the rise. 

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