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Workers' compensation influences outcome of carpal tunnel surgery

Workers' compensation influences outcome of carpal tunnel surgery

Surgery is the most common treatment for carpal tunnel syndrome, a nerve problem in the hands and wrists. But patients who receive workers' compensation may take more time off work and be less satisfied with their recovery than those who do not receive workers' compensation, a new study shows.

Carpal tunnel syndrome causes tingling, pain or numbness in the hands and wrists. People who engage in repetitive movements, such as grasping tools, scanning groceries and typing, are most at risk.

School of Medicine researchers surveyed 166 people who had undergone the surgery during an eight-year period. Eighty-one percent of those who had received workers' compensation reported residual symptoms, compared with 49 percent of those who had not. The former returned to work 12 weeks after their surgeries, whereas the latter took only three weeks to get back on the job.

"So our study suggests that the workers' compensation system in some way affects outcomes of carpal tunnel surgery," said Philip E. Higgs, M.D., assistant professor of surgery and of occupational therapy. Higgs was lead author of the study, which was described in a recent issue of the Journal of Hand Surgery.

A common problem

Carpal tunnel syndrome is one of the most common problems encountered by hand surgeons. It develops when a bone and cartilage tunnel in the wrist narrows and presses on the median nerve. The symptoms often are troublesome during the night, and they can prevent patients from carrying out even simple tasks.

A Bureau of Labor Statistics survey found that carpal tunnel syndrome accounted for 41,000 (or 1.8 percent) of the 2.25 million work-related injuries and illnesses among private industry employees in 1993. The syndrome accounted for 3.2 percent of work-related injuries and illnesses in manufacturing industries, where workers are most likely to engage in repetitive movements of the hands and wrists.

Repetitive-motion injuries caused longer absences from work -- a median of 20 days -- than any other occupational injury or illness, the survey found. So the syndrome is a significant item in the cost of workers' compensation, which pays the medical expenses and lost wages of workers who are injured on the job.

The National Center for Health Statistics found that 32,000 carpal tunnel patients were discharged from non-federal hospitals in 1992. So Higgs and his colleagues wanted to determine whether the availability of workers' compensation influenced discharged patients' recovery. "In surgical circles, there has been a suspicion that people covered under workers' compensation have a different post-operative course than those who are covered by conventional insurance or are self-paying," he explained.

The researchers surveyed 166 people by phone, inquiring about job status and duties, pain, numbness and nocturnal symptoms. They chose the subjects at random from 1,700 patients who had undergone carpal tunnel surgery at the Washington University Medical Center between 1984 and 1992. The average time since surgery was 42 months. One-hundred-thirteen of the subjects had received workers' compensation, whereas 53 had not. The survey excluded people who were retired, unemployed, homemakers, had non-related medical problems or had undergone their surgeries within the previous 18 months.

Adverse effects

The two groups differed in job stability as well as in time off work and presence of residual symptoms, the survey found. Half of the workers' compensation patients had changed jobs since the surgery, and 65 percent of these attributed the change to carpal tunnel syndrome. Only one-quarter of the other patients had changed jobs, and only 14 percent of these blamed the switch on residual symptoms.

"So our data support what has only been implied in the past -- that our workers' compensation system has some adverse effect on the outcome of this particular surgical procedure," Higgs said.

The study speculates on differences between people who receive workers' compensation and those who do not. First, the former may be convinced that carpal tunnel syndrome is an injury rather than a disease and therefore may expect to recover completely. Second, such workers may be tempted to prolong recovery in hope of further financial gain. Third, employees who receive workers' compensation may have more than one repetitive motion disorder, so a successful carpal tunnel surgery would not be expected to relieve all of their symptoms.

-- Linda Sage

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