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Carpal Tunnel Syndrome

Overview

Carpal tunnel syndrome is pain or numbness in the hand, wrist, or arm that is caused by pinching of a nerve in the wrist.

The carpal tunnel is a narrow passageway in your wrist, composed of bone and ligaments. The median nerve and tendons pass through the tunnel. The median nerve controls sensation to the thumb, index, and middle fingers as well as the half of the ring finger that is next to the middle finger. The nerve also controls some of the muscles that move your fingers. Anything that causes pressure on the median nerve may cause the symptoms of carpal tunnel syndrome.

Usually, we are able to diagnose carpal tunnel syndrome by evaluating your medical history and the results of a physical exam. Sometimes we may need to refer you for a nerve conduction test to confirm the diagnosis.

Treatments include:

• Avoidance of sustained wrist or palm pressure
• Avoidance of prolonged wrist extension and flexion
• Wearing of a wrist splint at night
• A cortisone injection into the wrist
• Physical therapy

We may recommend surgery if these treatments do not help or if your symptoms are severe.

Symptoms

Symptoms of carpal tunnel syndrome vary and may include:

• Numbness, tingling, electric shock-like sensation, and pain in most of the fingers
• Pain that can also be felt in the entire palm and can sometimes radiate into the arm
• Pain at night that can disturb sleep
• Muscle weakness or clumsiness of the hand

The symptoms often occur when you are involved in activities that require frequent or persistent flexing or extending of the wrists.

Other simple daily tasks that are repetitive can also bring on the symptoms. These may include cooking, driving, or holding a book. Shaking the hand may return normal feeling. Try to keep your wrists straight and avoid leaning on them.

Diagnosis

We use a range of diagnostic tools to evaluate your wrist. Initially, we will ask you to describe your symptoms and go through a comprehensive physical examination. The exam will include some or all of the following:

• Carpal compression test. We apply direct pressure over the carpal tunnel to see if this reproduces the symptoms in the hand.
• Phalen maneuver. We ask you to flex your wrist for 30 to 60 seconds. If this movement produces numbness, tingling, or pain, you may have carpal tunnel syndrome.
• Muscle strength test. We check the strength of muscles in your thumb by asking you to try and straighten the thumb while someone else holds it back.
• Nerve conduction study. We place electrodes on the skin of your hand and wrist and pass small electric shocks through the median nerve. This shows us if the nerve is transmitting electrical impulses in the carpal tunnel at normal speed. Pressure on the median nerve can slow down these impulses.

Additional tests

X-rays or other imaging studies do not help us to diagnose carpal tunnel syndrome. If we suspect that your symptoms are caused by something other than overuse of the wrist, we may order additional tests, including blood work.

Causes

Carpal tunnel syndrome is caused by increased pressure on the median nerve as it passes through the tight space in the wrist. This can be due to compression or inflammation. Often it is not possible to identify what causes the pressure on the median nerve to increase. However, there are many factors, including your medical and family history, that may be associated with this increase in pressure. These include:

• Obesity.
• Family history of carpal tunnel syndrome.
• Diabetes.
• Hypothyroidism, or low thyroid function. The median nerve may be more susceptible to increased pressure in people with hypothyroidism.
• Pregnancy. Swelling and fluid retention can increase pressure on the median nerve.  
• Kidney failure (end-stage renal disease). End-stage renal disease and dialysis can affect the median nerve in a number of ways. For example, the median nerve may receive a reduced flow of blood during dialysis, or the vascular access created for dialysis may press on the nerve.
• Female gender.
• Rheumatoid arthritis and other connective tissue disorders.

The kind of work you do, your behaviors, and your use of body mechanics may also exacerbate these symptoms. Here are some examples:

• Flexing the wrists while sleeping, reading, or driving.
• Clenching the steering wheel while driving.
• Repetitive activities. Certain occupations that require repetitive flexing of the wrists may increase your risk of developing carpal tunnel syndrome.
• Repeated flexing causes the tendons to swell and press on the median nerve. Construction work, nursing, and jobs that require typing and mouse use on the computer all fall into this category.

Prevention

We recommend that you understand the activities that increase your risk of developing carpal tunnel syndrome and take steps to manage them. If you already have carpal tunnel syndrome, limiting these activities may help control your symptoms. For example:

Avoid repetitive hand motions with a bent wrist. Keep your wrist straight when you are involved in the following activities:

• Using the computer, typing, or using the mouse
• Writing
• Driving
• Using scissors, power tools, pliers, screwdrivers, or other tools
• Playing the piano
• Knitting, crocheting, and needlepoint

Take frequent breaks if you must repeat hand motions. Rest your hand for at least 5 minutes every hour. Stretch your fingers and thumb and change your grip.

Type softly on your keyboard. A gel pad may help to cushion your wrist and keep it in the right position.

Be careful with your posture. Keep your shoulders straight.

Consult an ergonomic specialist. If you are uncomfortable, ask for an ergonomic evaluation at work, if one is available to you. An ergonomic specialist may be able to improve the configuration of your workstation and improve your wrist position and posture.

Avoid sleeping on your hands. Try to keep your wrists straight while you sleep. Wearing wrist splints while sleeping may help.

Wear a wrist splint at night if you are having symptoms. You may also wear the wrist splint during the day to decrease symptoms.

Nonsurgical Treatment

Nonsurgical treatments can be effective for people with carpal tunnel syndrome. We will discuss the preventive measures and treatments that are most appropriate for you. Sometimes we recommend a combination of treatments that may include the following:

Good posture and ergonomics

Avoid poor posture or overuse of the wrist. We can talk to you about using good ergonomics; for example, when you are using a computer workstation.

Wrist splints and ice

• We can recommend wrist splints and talk to you about using them during sleep.
• We can also tell you how to use wrist splints during the day while you are participating in activities that require you to flex your wrist.
• Icing your wrist up to 3 times each day, for 10 to 15 minutes each time, can be helpful. This is particularly important right before you go to bed. We can show you how to use ice effectively.

Anti-inflammatory pain relief

• Over-the-counter (OTC) nonsteroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen, may treat the tendinitis that is causing carpal tunnel syndrome.
• Even though you do not need a prescription for OTC NSAIDs, you should still be careful to consult the package so that you take the correct dosage.
• Also, please be aware that OTC NSAIDs can interact with other medicines you may be taking and cause problems for people with various medical conditions.
• If you have a complex medical condition, or if you are pregnant or trying to get pregnant, or if you have been taking OTC NSAIDs and they do not relieve your symptoms, please let us know so that we can recommend an alternative.

Corticosteroid injections

• If your symptoms are severe, we may recommend a corticosteroid injection directly into the wrist.
• Corticosteroids, such as cortisone, decrease inflammation, which can relieve some of the pressure on the median nerve.

Surgical Treatments

Carpal tunnel release surgery

If more conservative treatments do not relieve your symptoms, we may recommend carpal tunnel release surgery. During surgery, we cut ligaments or tissue that is pressing on the median nerve. Most commonly, we cut the transverse carpal ligament that lies directly over the median nerve. We perform the surgery in one of two ways:

• Open incision. We make a small cut in the palm of your hand to access the carpal tunnel area.
• Endoscopy. We make one or two small incisions in the wrist and/or palm. We then insert an endoscope – a lighted tube with a camera and surgical instruments attached – into the incision. This allows us to see the structures in the wrist and to treat the problem.

These are outpatient surgeries that require only local anesthetic. We will also offer you medications to help you relax during the procedure.

Related Health Tools:

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