Numbness, tingling signs of carpal tunnel syndrome

Mention carpal tunnel syndrome and everyone nods like they know what it's about. The words are familiar in this age of assembly lines and computers, but what exactly is it?

Simply put, carpal tunnel syndrome, or CTS, is a physical problem caused by pressure on a nerve. Like an electric cable formed of bone and ligament, the carpel tunnel houses many "wires" flexor tendons that allow hand and finger movement and the median nerve. The problem arises when something irritates the tendons causing their covering, the tenosynovium, to swell. Swelling makes the tight tunnel tighter, squeezing the median nerve against the transverse carpal ligament. As a result, the median nerve can't function properly.

Typical symptoms are numbness, tingling and pain in the hand, but the earliest signs might be tired hands or sore wrists. Untreated, symptoms worsen and can lead to permanent damage.

CTS usually involves the parts of the hand served by the median nerve: thumb, index finger, middle finger and half of the ring finger. There can also be forearm and neck pain. People often notice the symptoms most at night, and a person may wake up feeling his or her whole hand is numb.

"There might be loss of feeling so that you have trouble discriminating between a dime and a penny in your pocket. You might have to grip things harder to get a better feel ... . For the laborer who uses shovels, he or she would have trouble detecting blisters as early as others," said Marc Allen, occupational therapist and certified hand therapist, St. John's Outpatient Physical Therapy.

Who is likely to develop CTS? "It is three times more common in women than in men and generally occurs between the ages of 30 and 60," said Becky Crocker, physical therapist with JobSafe of Missouri.

According to a study at the Hasslehom-Kristianstad Hospital, Sweden, a link exists between being overweight and having CTS. They also found CTS sufferers were more likely to be blue-collar than white-collar workers.

Blue-collar workers generally suffer from CTS as a cumulative trauma disorder, the study stated. But CTS can result from direct traumas, such as wrist fractures, or be associated with medical conditions including pregnancy, PMS, menopause, cancer or tumor, thyroid imbalance, bleeding disorders, rheumatoid arthritis, renal failure, diabetes and high blood pressure.

The severity of the condition defines the treatment. Nonsurgical methods include exercise; medication; modifying activities; a split, brace or cast; and high doses of Vitamin B-6 (a more controversial treatment.)

"The whole point of some of the common exercises we do in therapy is to improve nutrition in the area of the median nerve, so we use modalities that increase blood supply. We do exercises to increase blood supply to the tendons, to ensure they have normal length and are moving well. We try to look at posture and trace the nerve as it goes up the arm into the neck," Allen said.

There are two surgical options. Carpal tunnel release is most common. It involves an incision in the palm, then through the palmar fascia, and finally the transverse carpal ligament is cut. Endoscopic carpal tunnel release uses a smaller outer incision.

Prevention is the best option and might be as simple as practicing job rotation for example, two hours on the computer, file, then back to the computer or finding alternative ways to do the same job.

"Professional athletes work out year-round for one game. Most people work eight to 12 hours and don't prepare their bodies for the job; they don't warm up or cool down," said Shannon Tranmer, OTR/L, CHT, hand clinic occupational therapist at the Regional Center for Sports Medicine and Rehabilitation, Cox Health Systems.

She said computer users should do hand and finger exercises before they start keyboarding.

Also, "the position of the wrist is important in prevention. Picture a rope stretched across a flat surface it has no friction. Across a bent surface, there is friction. It is the same with the wrist. Prevention might involve trying to change tool handles," making them larger or using a different slant, Tranmer said.

Awareness is important. For example, "If someone did a work-injury report and it said hand pain, this could be a pre-indication of what is to come. If supervisors get those reports, they need to look at the job and what the employees are doing," Crocker said.

"If I have numbness and tingling and it becomes constant, I'd definitely ask questions of the company nurse or family physician," Allen said, adding, "When it gets to the point it affects your ability to function, definitely ask about it."

CTS is costly to individuals and employers. "Carpal tunnel syndrome leads, on average, to more days away from work than any other workplace injury," Crocker said.

For more information, check out A Patient's Guide to Carpal Tunnel Syndrome at

http://www.sechrest.com/mmg/reflib/ctd/cts/cts.html

on the World Wide Web.