What Is Carpal Tunnel Syndrome?
Carpal tunnel syndrome is a pinching or inflammation of the median nerve, the nerve that travels down the front of the forearm and wrist. It’s called a mixed nerve because it supplies sensation to three and a half fingers — typically the thumb, index, long, and ring fingers, and it provides muscle strength to the hand, particularly the thumb.
That nerve travels through a tunnel in the wrist before it goes to the muscles to supply strength and to the fingertips to give sensation. In that tunnel, the nerve can be compressed — it can be squeezed or irritated, and as a result, the nerve doesn't function normally anymore.
What Are the Symptoms of Carpal Tunnel Syndrome?
When the median nerve gets compressed or irritated there is a loss of function, and over time this gets worse and worse. People with carpal tunnel syndrome can notice numbness, tingling, weakness, and pain.
It’s also common to lose dexterity when you have carpal tunnel syndrome. You may start to drop objects or have trouble with what we call fine manipulation, which is required for actions such as picking coins off a tabletop or closing a jewelry clasp.
If you don’t talk with your doctor or seek treatment, the problem tends to progressively worsen, and may even become irreversible. When this occurs, a person can have horrible pain or numbness — it can feel like your hand is in an electric socket 24/7. Eventually, it can be so severe that the muscles that are normally fed by this nerve shrink over time or atrophy — they literally wither away, at which point a person is left with a permanent disability.
What Are the Causes or Risk Factors of Carpal Tunnel Syndrome?
Carpal tunnel syndrome happens when the tendons (which connect muscle to bone) in the carpal tunnel swell and become inflamed, which leads to less room for the nerve. It causes compression.
Many people think of typing as the main cause of carpal tunnel syndrome, but that’s just one of several reasons someone can develop carpal tunnel syndrome. The most common reason for carpal tunnel syndrome is what we call idiopathic or spontaneous — it just happens.
There are some predisposing factors that are associated with an increased risk of a person developing carpal tunnel syndrome. Women are more than three times more likely to get carpal tunnel syndrome than men, and during menopause and pregnancy there’s additional risk because the hormones are fluctuating so much.
Sometimes, there seems to be a hereditary component to carpal tunnel syndrome — sometimes I will treat someone whose mother and grandmother both have it.
Other chronic conditions, including being overweight or obese, underlying inflammatory disease, such as gout, rheumatoid arthritis or even osteoarthrosis in the vicinity of the median nerve, hypothyroidism (low thyroid levels), and diabetes are all associated with a higher risk of carpal tunnel syndrome.
Some jobs or activities can increase the risk of carpal tunnel syndrome. Any repetitive motions or repetitive stress, including activities such as typing on a keyboard, gripping a steering wheel, or using power tools can cause inflammation of the tendons in the carpal tunnel, which, in turn, can lead to carpal tunnel syndrome.
How Is It Diagnosed and Treated?
Carpal tunnel syndrome is a clinical diagnosis, which means there’s no “yes or no” test such as a blood test that can tell us right away if a person has it. The diagnosis is made by putting together the patient’s symptoms along with a physical examination. Part of the exam includes provocative tests — they’re called provocative because we are trying to provoke the symptoms of carpal tunnel syndrome. We do things like tap the inside of the wrist or ask patients to bend their wrist in order to bring about the symptoms that they’re noticing when they’re at home or at work.
After hearing the symptoms and performing the tests, we have a good sense of whether someone has carpal tunnel syndrome or perhaps another problem masquerading as carpal tunnel syndrome. These conditions can include a pinched nerve in the neck or forearm, or something called thoracic outlet syndrome, which is a pinched nerve between the neck and the underarm.
If we suspect someone has carpal tunnel syndrome, we send for an electrodiagnostic study called an EMG (electromyogram). This uses an amazing piece of equipment that measures the speed of nerve signals in thousandths of a second. An EMG test can reveal if the nerve is slowing down as it crosses the wrist or if it’s slowing down in the neck as well as the wrist, which is called a double crush syndrome.
The test shows us if there’s a “traffic jam” in the signals. Is it harder for the nerve signals to get across the wrist because the nerve isn’t healthy, because it’s pinched, squeezed, or compressed? It’s like a garden hose — if it’s pinched or you step on it, the water in the hose slows down and there’s less water that comes out. In the same way, the nerve signal can get slowed down in carpal tunnel syndrome.
An EMG can confirm a carpal tunnel syndrome diagnosis, determine the level of severity, and help us determine which treatment option is best.
A more conservative, nonoperative treatment might be appropriate for someone who has intermittent problems that appear only during certain times or activities. Therapy could include strategies such as changing how they hold their wrist or using a splint to keep the wrist straight while they sleep or do certain activities.
For people with moderate carpal tunnel syndrome, we may need to use anti-inflammatory medicine such as NSAIDs or injectable or oral steroids to reduce inflammation and pain. Occupational therapy can also be used to improve symptoms and inflammation as well.
Those treatments usually work in a majority of people with mild to moderate carpal tunnel syndrome, but sometimes surgery is necessary in more severe cases.
There are two types of surgery — the original open technique, which is when we cut open the wrist and cut the carpal ligament, pressing on the nerve, to enlarge the carpal tunnel. The second type is a closed technique, also known as endoscopic carpal tunnel surgery. This surgery is less invasive — it only requires tiny incisions where we use thin tools and a camera, and we’re able to just cut just the ligament without having to cut all the tissues to get down to the ligament.
Both operations work well and heal with minimal scarring; by six months, the results of the surgeries are the same. There are advantages to the endoscopic approach — it involves less pain and heals faster, and you’re able to return to doing activities up to five times faster than with the open approach.
I’ve had patients pursue alternative or nontraditional approaches such as acupuncture or chiropractic adjustment. These treatments may be helpful for mild carpal tunnel syndrome, but typically aren’t beneficial for more severe cases.
Newer therapies that try to address carpal tunnel syndrome, like platelet rich plasma (PRT), amniotic fluid, or stem cells can be very expensive, and they don’t have the clinical evidence to demonstrate that they really make a difference.
What Is the Prognosis for Carpal Tunnel Syndrome?
The longer a person has untreated carpal tunnel syndrome, the more likely it's going to progress or worsen over time, thereby increasing the risk of irreversible or permanent damage. Listen to your body. If you begin to experience any of the symptoms of carpal tunnel syndrome, talk with your doctor so that the appropriate measures can be taken. The good news is that even when surgery is necessary, in more than 90 percent of cases the symptoms are improved or there is total resolution of the problem.