Study to investigate carpal tunnel syndrome

A five-year, $2.5 million grant from the National Institute for Occupational Safety and Health may help employers determine which employees are more likely to get carpal tunnel syndrome and other hand, wrist and elbow problems. Bradley A. Evanoff, M.D., the Sutter Associate Professor of Occupational, Industrial and Environmental Medicine at Washington University School of Medicine in St. Louis, is leading the study.

Carpal tunnel is a painful progressive condition caused by compression of a key nerve in the wrist. Approximately two out of every 1,000 workers will experience carpal tunnel syndrome every year, leading to significant medical expenditures and lost time from work.

The average lifetime cost of carpal tunnel syndrome, including medical bills and lost time from work, is estimated to be about $30,000 for each injured worker.

The risk of developing carpal tunnel syndrome is not confined to people in a single industry but is seen more often in hand-intensive work requiring frequent task repetition and forceful hand exertions. Jobs at higher risk include food processing, manufacturing and assembly jobs. Personal risk factors such as age, gender, obesity and other diseases also contribute to the risk of developing carpal tunnel syndrome.

One strategy to reduce the risk of carpal tunnel syndrome is to screen workers for pre-existing abnormalities of the median nerve, the nerve involved in the development of carpal tunnel syndrome. Workers with abnormalities are then kept out of jobs requiring high-hand force and repetition. Although this practice is used by many employers in the United States, there are both scientific and social controversies regarding its use.

In this study, Evanoff and colleagues will evaluate whether screening is a useful and cost-effective preventive strategy. They also will study how personal risk factors and job-related exposures contribute to the cause of carpal tunnel syndrome.

“This study will provide guidance to employers and employees in deciding what policies and practices will best prevent this common and disabling condition,” Evanoff said.

The researchers are recruiting local employers in order to screen approximately 1,200 new workers in the metropolitan area. Screening will consist of a brief questionnaire on medical history and symptoms, an examination of hands and arms, and nerve conduction testing of both wrists. Study participants will be interviewed by telephone six months, 18 months and 36 months after the initial testing.

Evanoff and colleagues then will review the data and determine who developed carpal tunnel and other hand, wrist and elbow problems. People will not be turned away from jobs based on screening during the study.

Participation in the study is voluntary, and subjects will be compensated for their involvement.

Employers participating in the study will learn about specific physical exposures and health changes in their workforce over time. No individuals will be identified. Employers also will receive an analysis of whether screening would be an effective strategy in their workplace.

“This study will test a screening practice that is being rapidly disseminated in the workplace despite little study of its effectiveness,” Evanoff said. “We hope our study will help people make decisions about the best use of resources to prevent carpal tunnel syndrome and other hand and arm conditions.”