|
Q. Our heavy manufacturing company has used the same basic tools and procedures for more than 20 years. Recently, we have seen a significant outbreak of carpal tunnel syndrome which has not been observed in similar plants under identical circumstances. All have been deemed to be "work related." Is CTS always work related? What can we do to reduce this epidemic?
A. Carpal tunnel syndrome (CTS) is a condition in which the median nerve is compressed, or "entrapped," by the bones/ligaments within the carpal tunnel at the wrist. Increased pressure on the nerve can lead to a variety of problems which can include pain, numbness, tingling, or weakness in the hand or arm. Some cases of CTS are discovered incidentally before any symptoms are noticed. CTS symptoms can often be resolved by simply using a splint at night to correct self-induced wrist bending.
Studies have shown that arm, wrist and hand complaints similar to CTS are quite common independent of the type of work involved. These studies indicate that about 15 percent of the general population may experience CTS-like symptoms such as numbness/tingling, muscle pain and tendon discomfort. However, only about 20 percent of these were verified to be CTS.
Nearly three dozen medical conditions are known to directly cause CTS. Among the more common conditions are diabetes, pregnancy, arthritis, thyroid conditions, gout, and wrist fractures. The workplace is just one factor in CTS presentation; and when it does occur, it’s often related to repeated awkward wrist positioning, recurrent forced wrist flexion/extension, or continuous exposure to significant vibration.
Anything that causes a decrease in the wrist’s carpal tunnel size – including a fracture or deformity – can cause CTS. Congenitally small carpal tunnels are thought by some to be a primary factor of this disorder. Increased pressure on the median nerve can result from a variety of medical conditions that can increase the amount of material within the tunnel. These conditions can include diabetes, thyroid disorders, infections and so forth. Obesity can be a significant factor in CTS. Medications that increase fluid retention, such as birth control pills, female hormones and others, have also been implicated.
|
The commonly held belief that intense keyboard use was the source of significant work related CTS was disproved by a 2001 Mayo Clinic study. The study found that extensive keyboard users had no greater risk of developing CTS than those who didn’t use keyboards as much. Although there have been studies that suggested a strong relationship between repetitive activities and CTS, recent scientific reviews of those studies have discovered significant flaws such as a failure to exclude study subjects who had other medical problems that were strongly associated with CTS. The American Society of Surgery of the Hand has issued a position statement which cast doubt on the notion that there is a link between work and CTS and noted that the cause of CTS is usually unknown. In addition, the National Institute of Neurological Disorders and Strokes has said there is little clinical data to prove whether repetitive and forceful movement of the hand/wrist during work or leisure can cause CTS.
Once CTS is suspected, a detailed investigation is required to determine the source of the symptoms. However, it’s not always possible to determine the source. A complete analysis of all data – such as blood studies, a review of job activities and, if necessary, x-rays – is recommended for all with suspected CTS. Electrical studies are necessary to validate median nerve compression. The preliminary review assessing a possible link to the workplace can be done before the nerve conduction study. If the prevailing factors do not appear to be associated with the workplace, then further care can continue with the employee’s primary health care provider. Basic management, including splitting and use of anti-inflammatory medication, can often resolve many common arm/hand symptoms.
The most important factor in management of CTS is early symptom identification. Daily or weekly monitoring of workers can help identify those who may be at risk, as well as ergonomic activity review and timely referrals to health care providers. Significant delays by employees in reporting their physicians’ diagnosis to their employers can create roadblocks in preventing future work related complaints. The new Workers Compensation Law requires occupational diseases (such as CTS) be reported in writing within 30 days of diagnosis. |