Carpal Tunnel Syndrome (CTS), a personal illness categorized under cumulative trauma disorder or repetitive motion trauma, is the fastest growing occupational illness in the United States. Activity centers inside the wrist in the carpal tunnel, a collection of 8-10 tendons surrounding the median nerve. The tendons slide easily encased in the synovial sheath, however when subjected to repeated, limited range motions (i.e. typing), the sheath can swell and fill with fluid, putting pressure on the median nerve and sending pain into the fingers. Symptoms of CTS are the burning, prickling, and tingling within the wrist or first three fingers and thumb. The highest prevalence of self-reported CTS is in the mail service, health care, construction, assembly line, and fabrication industries. In the past, CTS has been limited to the manual labor industry, but a trend is rising in the computer industry as well. American workers who use keyboards daily in work involving extensive data entry and word processing make up 45-75 million of the working population. Twenty-five percent of these operators are inflicted with CTS, and that percentage could double by the year 2000.
Risk factors most strongly associated with exposure to CTS are the repetitive bending or twisting of the hands and wrist at work and the use of vibrating tools. Other factors are the wrist posture and shape while working, table height, the angle of the elbows, and repetitive motion. Factors which are not work related can also contribute to CTS. These include age, race, gender (studies have found that for unknown reasons, females are at higher risk than males), diabetes, and arthritis. Obesity is also a risk factor because water retention adds to muscle and tension stress. Workers with a Body Mass Index (BMI) higher than 29 are four times more likely to present with median mononeuropathy than those with a BMI of less than 25.
Although there are a great number of elements putting workers at risk, CTS is easily preventable and can be controlled. Some preventive measures include resting hands periodically during repetitive activity, exercising to condition and strengthen the hand/arm muscles, minimizing repetition of any movement, varying the position of the arm when performing an activity, and maintaining, not increasing, the pace of work. Reasonable weight loss and diet adjustments can also alleviate CTS. Preventive measures are divided into two main categories, ergonomics and behavior change measures.
In the computing industry, ergonomics has been implemented in the chair, desktop, computer keyboard and mouse. A debatable topic has been the wrist rest, designed to improve wrist posture and lessen wrist extension. It is still unknown whether these help as a comprehensive ergonomics plan or not. The rest should improve wrist posture and support the arm and it should not exert pressure on the Carpal Tunnel area. The wrist rest should not be confused with the palm rest, because it supports only the palm. Users can benefit from the wrist rest because it doesnt allow awkward keystroke or wrist extension. Examples of behavior change measures are worker training, education on correct posture during repetitive tasks, and medical intervention, such as usage of an anti-inflammatory agent (i.e., Aspirin), or surgery, to correct the injury.
After being diagnosed with CTS, there are several levels of treatment. Wrist splinting is efficient yet the angle of immobilization is varied. A blind study compared the relief between splints at 20° and neutral extensions. The study found the neutral angle provided superior symptom relief. Iontophoresis of dexamethasone sodium phosphate has been used for years in treatment of many musculoskeletal inflammatory disorders, and is reported to be used in CTS treatment as well. A non-randomized study using wrist splinting with non-steroidal anti-inflammatory medication and iontophoresis of dexamethasone sodium phosphate revealed a success rate comparable with splinting and injection of dexamethasone into the carpal tunnel space. For a six-month follow-up, out of 23 cases of early to mild CTS, 17% were successfully treated with splints plus non-steroidal anti-inflammatory medications alone. Of the 83%, which failed this treatment and proceeded with iontophoresis of dexamethasone, 58% had a positive response rate. Surgery is generally used as a last resort. The former procedure was to cut the transverse carpal ligament, however an endoscopic procedure was developed to open the carpal tunnel through a small incision in the wrist. Following surgery and treatment, it is estimated 23% of CTS patients return to their profession.
Preventative measures are being taken in various at-risk industries, however construction is an industry where risk still outweighs prevention. A study of 18 disabled and 47 active and retired sheet metal workers showed that symptoms of neck, arm, and hand pain are common in sheet metal workers who are actively working. CTS/hand pain is associated with more time working in the shop, and shoulder pain/injuries are associated with working overhead. This data suggests a division of work tasks in the construction industry increase the risk of Cumulative Trauma Disorder.
Both private and public legal/medical sources have confirmed
repetitive strain injuries as the
fastest growing occupational hazard today, costing billions of
dollars and millions of workdays each year. The cost associated
with CTS and Cubital Tunnel Syndrome
(CBTS) is immense, each accounting for $1 of every $3 spent for
workers compensation, with the cost being $3,500 to $35,000 per
case. Repetitive stress injuries have the highest reported total
average for workers compensation cost per case from $14,000 to
$29,000. The occurrence of CTS as a work-related injury is on
the rise, however some patients have had trouble being reimbursed
by their insurance for these injuries. In a New York Occupational
Health Clinic, 79% of the claims werent initially accepted by
the workers compensation insurer and of those challenged cases,
96.3% were accepted later as work-related injuries. Mean time
from claim to settlement was 429 days, physician treatment and
workers compensation board approval 226 days, and surgery authorization
from the board was 318 days.
In its most severe form, CTS can become a lifelong disability that prevents the afflicted patient from performing physically stressful and everyday occupational duties. CTS is a disorder that should be carefully monitored and controlled in all work fields, but workers should not be dismayed by the high risk factors. Through prevention, treatment, and acceptance in the work field, CTS is a personal illness that can be confronted and defeated.
- Anti-inflammatory agent: An agent that counteracts or suppresses the inflammatory process.
- Behavior change measures: Changing the protocol of high risk job tasks or occupations.
- Body Mass Index (BMI): A person's weight in pounds divided by height in inches squared, multiplied by 705.
- Cubital Tunnel Syndrome (CBTS): Compression or injury of the ulnar nerve in the cubital tunnel.
- Cubital tunnel: Passageway between the bony prominence of the inside of the elbow (medial epicondyle) and the tip of the elbow (olecranon process).
- Cumulative Trauma Disorder (CTD) Response to the repetitive motion and overuse of a muscle in an incorrect or static posture.
- Carpal Tunnel Syndrome (CTS): A condition caused by compression of a nerve where it passes through the wrist into the hand and characterized especially by weakness, pain, and disturbances of sensation in the hand.
- Dexamethasone: A synthetic glucocorticoid C22H29FO5 used especially as an anti-inflammatory agent.
- Ergonomics: The study of how the laws of nature affect you and your work environment. In an office environment, this includes interaction with workspace, computers, tools, and furniture.
- Iontophoresis: The introduction of an ionized substance (as a drug) through intact skin by the application of a direct electric current.
- Median mononeuropathy: A disorder involving loss of movement or sensation to an area, caused by damage to the median nerve.
- Median nerve: The nerve that takes its course along the middle of the arm and forearm through the hand, lying between the ulnar and musculo-spiral and radial nerves.
- Repetitive motion trauma: The injury to living tissue caused by movement applied to muscles and joints the same way all the time.
- Repetitive strain injuries: A category of injuries involving damage to muscles, tendons and nerves caused by overuse or misuse; these injuries can result from a single incident or develop slowly over time.
- Synovial sheath: An encasing which serves to facilitate the gliding of tendons in the osseo-fibrous canals through which they pass.
Carla R. McMillan
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- Editor, Conference Papers Index, EIS: Digests of Environmental Impact Statements
- B.A. (English), George Mason University