Carpal Tunnel Syndrome is a common condition. It occurs when the nerves that run into the hand are impinged or squeezed when they travel through the wrist. Symptoms include pain, numbness, and tingling in the hands and arms. Carpal Tunnel Syndrome has become a controversial diagnosis in workers' comp claims and L&I claims. The controversy comes from an evolving medical understanding of what causes the condition.

Industrial injury or occupational disease?

If a workers' comp claim is allowed for carpal tunnel syndrome, it is usually allowed as an occupational disease. This is because the condition tends to develop gradually over time as opposed to stemming from a sudden traumatic event. It is not usually an industrial injury. However, more and more frequently, claims for Carpal Tunnel Syndrome are being rejected.

There is a popular belief that excessive typing causes Carpal Tunnel Syndrome. In contrary, there is a significant body of medical research suggesting that repetitive typing has little to do with the development of the condition. In fact, the medical research suggests that there are significant non-occupational factors that contribute to Carpal Tunnel Syndrome. These factors include a person's age, body mass index (BMI), gender, biopsychosocial factors, comorbidity, diabetes, and genetics. In other words, there are many reasons a person may develop Carpal Tunnel Syndrome that are unrelated to work activity. These same medical studies suggest there is insufficient evidence to link keyboarding activity to the development of Carpal Tunnel Syndrome. The publication titled The AMA Guides to the Evaluation of Disease and Injury Causation outlines these findings.

Work conditions that cause Carpal Tunnel Syndrome

The fact that non-occupational factors may contribute to or cause Carpal Tunnel Syndrome does not mean it can’t develop from distinctive conditions of employment. However, I have recently seen Carpal Tunnel Claims rejected based on a blanket statement that work activities don’t cause the condition. This simply isn’t true. The same studies identifying non-occupational factors causing Carpal Tunnel Syndrome also indicate occupational factors causing the condition. According to the studies, there is strong evidence that work activities involving a combination of force and repetition, as well as force and posture, cause Carpal Tunnel Syndrome. The study also reveals that highly repetitive work in combination with other factors, and forceful work, cause Carpal Tunnel Syndrome.

Despite the popular misconception that keyboard typing causes Carpal Tunnel Syndrome, there are work activities that are proven causes. Work involving repetitive forceful grasping, awkward hand postures, forceful work, and highly repetitive work combined with other factors such as lifting, pushing, pulling and pinching may place workers at risk of developing the condition. Therefore, it is not appropriate for a claim to be rejected on the basis that Carpal Tunnel Syndrome is not caused by occupational factors. Determining whether a person's work activity causes Carpal Tunnel Syndrome requires careful consideration. Distinctive conditions of employment must be examined to determine if there is evidence connecting work activity to the condition.

L&I guidance and conclusions

For reference, look at L&I's own medical treatment guideline for Work-related Carpal Tunnel Syndrome. The guideline provides further support that occupational factors indeed cause Carpal Tunnel Syndrome. Moreover, the guideline provides information regarding required findings for the diagnoses to be accepted. It also contains information regarding L&I's preferred course of treatment for the condition.