One in five with symptoms may have carpal tunnel syndrome

July 13, 1999
Web posted at: 4:04 p.m. EDT (2004 GMT)

(CNN) -- Carpal tunnel syndrome (CTS) symptoms like wrist pain are common in the general public, but new research shows one in five persons with symptoms may actually suffer from CTS, according to an article in this week's Journal of the American Medical Association (JAMA).

Researchers based their findings on a February 1997 mail survey of randomly selected persons in southern Sweden, along with follow-up examinations and nerve testing.

CTS is a repetitive motion injury caused by the compression of the median nerve in the wrist. This nerve supplies sensation to the thumb side of the palm and to the thumb, the index finger, the middle finger and the thumb side of the ring finger.

The median nerve comes into the hand through a space between the wrist bones, or carpal bones, and the transverse carpal ligament, which is the membrane that holds the bones together. The space is called the carpal tunnel.

Those who suffer from CTS complain of pain, numbness and tingling in the hands. Repetitive tasks such as typing can cause repeated compression of the median nerve and be very painful. Some of those who suffer from CTS lose strength and feeling in their hands and have wrist surgery, with varying success.

CTS is a major portion of work-related upper-extremity disorders and results in considerable health-care costs, according to researchers at the Hassleholm-Kristianstad Hospital in Kristianstad, Sweden.

"Estimation of CTS prevalence rate in the general population may contribute to early diagnosis and effective treatment of symptomatic subjects and provide useful data for the interpretation of results of studies that estimate CTS prevalence in specific occupational groups," the authors wrote.

Of the 2,466 study participants, 354 reported symptoms of CTS. During the clinical examinations, 94 of those who reported symptoms were diagnosed as having CTS. Nerve conduction testing, which uses electricity to find damage in nerves, found 129 participants had abnormalities in the median nerve in the wrist.

Sixty-six respondents with symptoms were found to have CTS based on both the clinical examination and the nerve testing.

A small control group of 125 persons who did not have any CTS symptoms were also examined and tested. The electrophysiologic nerve test showed evidence of median nerve dysfunction in 23 of those participants.

Researchers found that among older persons, women were four times more likely than men to have confirmed CTS. Subjects with confirmed CTS also had a tendency to be overweight or obese, and blue-collar workers were more likely than white-collar workers to have CTS.

The JAMA study also found those who used excessive force with the hand for an hour or more each day were more likely to have CTS.

An accompanying editorial from doctors at the University of Michigan School of Public Health said the nerve conduction velocity tests (NCV), which the Swedish researchers used along with the oral history and physical exam to verify CTS in asymptomatic subjects, should be considered an important tool in the clinical assessment of CTS.

"However, test results need to be interpreted with more caution," the editorialists wrote. "NCV testing showed only 70 percent sensitivity among subjects with a diagnosis of CTS based on history and physical examination and a high rate of false-positive results (approximately 76 percent). Practitioners need to recognize these limitations and work to overcome them."