Are you at risk for carpal tunnel syndrome?
Carpal tunnel syndrome is a real pain—and women are three times more likely to get it than men. Find out the causes and treatmentsBy Michelle Villett
Aching, tingling or numbness in the wrists, hands and fingers: It could be the early signs of arthritis—or it could be carpal tunnel syndrome (CTS), which has similar inflammatory symptoms. In fact, arthritis can be a trigger for CTS, a condition that affects more than one in 20 Canadians and can be diagnosed in adults of any age. As well as the symptoms listed above, it’s also associated with “pins and needles,” burning sensations and difficulty picking up objects.
“The syndrome occurs as a result of pressure on the median nerve in the wrist,” explains Dr. Thomas Goetz, assistant professor in the department of orthopedics at the University of British Columbia and an upper extremity surgeon at St. Paul’s Hospital in Vancouver. “This nerve is located in the carpal tunnel, a narrow passageway through which the tendons that control finger movement also pass.” Pinching on the nerve restricts its supply of blood and oxygen and, left unchecked, may cause loss of muscle power and even atrophy.
Causes of carpal tunnel syndrome
Acute CTS can arise after an injury to the wrist—such as a fall or accident—that compresses space in the carpal tunnel. Usually, however, symptoms are gradual, due to a predisposing condition that causes the interstitial space (the space between cells and tendons) to swell and fill with abnormal tissue, leaving less room for the median nerve. Diabetes is the most common cause of this, but rheumatoid arthritis, hypothyroidism and congenital abnormalities (small wrists with a narrow carpal tunnel) can also set off this underlying mechanism. As well, “it tends to occur in women who are pregnant, lactating or perimenopausal, because their hormones can cause a lot of fluid accumulation,” says Dr. Jean Paul Brutus, a hand surgeon in private practice in Montreal. “Women are three times more likely to develop CTS, perhaps because the carpal tunnel itself may be smaller in women than in men.”
Researchers can’t say for sure that CTS can be brought about by repetitive movements, such as typing on a keyboard, working with vibrating tools or participating in sports like tennis. “There’s no question that certain activities can aggravate it,” says Goetz. “But it’s hotly debated as to whether they are a cause or have just made people who were already predisposed to it become symptomatic.” That’s why, if you suspect you might have CTS, he recommends the first line of treatment should be avoiding exacerbating activities and making ergonomic modifications to your work situation. “Sometimes this brings it under control,” he says.
Treatments for carpal tunnel syndrome
If the pain or tingling wakes you up at night or limits normal activities—or if resting your hands doesn’t give you relief after a few days— seek help from your GP, who may refer you to a specialist for a diagnosis. Your specialist may perform a nerve conduction test to discover any abnormalities in muscle response and then, particularly if the cause is a known short term condition, may treat it with a splint (which supports the wrist to aid recovery) or a cortisone injection (which reduces inflammation for up to nine months). “When symptoms are mild, sufferers may benefit from passively stretching their wrists and forearm muscles,” says Brutus. “But physiotherapy can help only in the very early stages.”
If you have mild symptoms, Brutus recommends extending the wrists, hands and fingers backwards (as if you are in a handstand) and holding for a count of five. Relax them and then make a tight fist with both hands before bending both wrists down. Hold for a count of five, and then straighten both wrists and relax for a count of five. Repeat this exercise 10 times, several times per week.
Surgical options for carpal tunnel syndrome
If such non-operative techniques don’t bring improvement within four to six weeks, surgery to open up the carpal tunnel is the next option. Goetz recommends surgery when symptoms keep getting worse, and when there is continuous numbness (an indication that the nerve is undergoing permanent damage).
The traditional approach is open carpal tunnel release surgery, during which a three-to four centimetre long incision is made in the palm of the hand over the carpal tunnel, cutting the transverse carpal ligament to provide more space for the median nerve. A newer, less-invasive technique is endoscopic carpal tunnel release, which involves the same action but through a smaller (one centimetre) incision in the forearm and using an endoscope—a telescope-like device with a tiny camera attached.
Both surgeries are performed in less than 10 minutes under local anesthetic and, unless permanent nerve damage exists, they will relieve numbness immediately. Soreness and weakness in grip resolve more gradually. The main difference between the two procedures is in healing time: It takes about eight weeks to fully recover from open surgery; endoscopic patients require half the time and may experience less pain. “Another advantage of the endoscopic method is that you can do both hands at the same time,” says Brutus, whereas, with open surgery on each hand, the surgery is usually done two to three weeks apart, in order to avoid infection in the incision. Long-term, however, studies by researchers at McMaster University in Hamilton, Ont., St. Joseph’s Health Centre in London, Ont., and Lund University in Sweden have found no difference in outcome or in patient satisfaction between the two options.
In terms of safety, the endoscopic procedure has a slightly higher complication rate, says Goetz, and the London study also found a slightly higher incidence of incomplete release of the median nerve. “You can’t see the ligament as well as you can with traditional surgery; sometimes a second surgery is needed.” Complications for both techniques can include minor infection, particularly in people with diabetes, and a small increase in wrist pain for up to three months.
Because fewer surgeons have the training to perform endoscopic carpal tunnel release, and there is limited access to operating rooms with the equipment required, it can take up to two years to reach the top of the waiting list for this surgery in Canada. Patients with poor access to medical care or severe symptoms may opt to go to private medical centres; in British Columbia and Quebec, for example, the cost is about $3,000. “However, new government funding models to reduce waiting times have made timely access to endoscopic surgery more available,” says Goetz.
How to prevent CTS
• Gently stretch your forearms and wrists several times a day.
• Avoid repetitive wrist motions, such as forceful grasping or bending the wrists up and down, without regular periods of rest.
• If you type for long hours, check the ergonomics of your workspace and make modifications where needed. A keyboard pad can keep wrists in a straight position and prevent compression caused by resting against the edge of a desk.
• Ensure any inflammatory conditions—such as diabetes or arthritis—are under good control.
• Quit smoking. Because it impairs the supply of blood and oxygen to tissues, it can cause pressure on the median nerve.