What is carpal tunnel syndrome?
Carpal tunnel syndrome is a common condition that causes pain, numbness, tingling, and weakness in the hand and wrist. It happens when there is increased pressure within the wrist on a nerve called the median nerve. This nerve provides sensation to the thumb, index, and middle fingers, and to half of the ring finger. The small finger (the “pinky”) is typically not affected.
Carpal tunnel syndrome was first described in the mid-1800s. The first surgery for the release of the carpal tunnel was done in the 1930s. It is a condition that has been well recognized by orthopaedic surgeons for over 40 years.
What is the carpal tunnel?
The carpal tunnel is a narrow canal or tube in the wrist. Similarly to a tunnel you could travel through by car, this part of the wrist allows the median nerve and tendons to connect the hand and forearm. The parts of this tunnel include:
- Carpal bones: These bones make up the bottom and sides of the tunnel. They are formed in a semi-circle.
- Ligament: The top of the tunnel, the ligament is a strong tissue that holds the tunnel together.
Inside the tunnel are the median nerve and tendons.
- Median nerve: This nerve provides feeling to most of the fingers in the hand (expect the little finger). It also adds strength to the base of the thumb and index finger.
- Tendons: Rope-like structures, tendons connect muscles in the forearm to the bones in the hand. They allow the fingers and thumb to bend.
Does carpal tunnel syndrome only happen to office workers or factory workers?
No. Many people with carpal tunnel syndrome have never done office work or worked on an assembly line. It affects people who use their wrists and hands repeatedly at work and at play. Anyone can get carpel tunnel syndrome, but it is unusual before age 20. The chance of getting carpal tunnel syndrome increases with age.
Who is at risk for carpal tunnel syndrome?
People at risk for carpal tunnel syndrome are those who do activities or jobs that involve repetitive finger use. Motions that can place people at risk of developing carpal tunnel syndrome include:
- High-force (hammering).
- Long-term use.
- Extreme wrist motions.
Many other factors can also contribute to the development of carpal tunnel syndrome. These factors can include:
- Heredity (smaller carpal tunnels can run in families).
- Hemodialysis (a process where the blood is filtered).
- Wrist facture and dislocation.
- Hand or wrist deformity.
- Arthritic diseases such as rheumatoid arthritis and gout.
- Thyroid gland hormone imbalance (hypothyroidism).
- A mass (tumor) in the carpal tunnel.
- Older age.
- Amyloid deposits (an abnormal protein).
Carpal tunnel syndrome is also more common in women than in men.
Symptoms and Causes
What causes carpal tunnel syndrome?
Carpal tunnel syndrome is caused when the space (the carpal tunnel) in the wrist narrows. This presses down on the median nerve and tendons (located inside the carpal tunnel), makes them swell, which cuts off sensation in the fingers and hand.
How often is hand pain caused by carpal tunnel syndrome?
While carpal tunnel syndrome is a common condition, it has a different set of symptoms from many other sources of hand pain. There are actually several similar conditions that cause hand pain. These include:
- De Quervain’s tendinosis: A condition where swelling (inflammation) affects the wrist and base of the thumb. In this condition, you will feel pain when you make a fist and simulate shaking someone’s hand.
- Trigger finger: This condition causes soreness at the base of the finger or thumb. Trigger finger also causes pain, locking (or catching) and stiffness when bending the fingers and thumb.
- Arthritis: This is a general term for many conditions that cause stiffness and swelling in your joints. Arthritis can impact many joints in your body and ranges from causing small amounts of discomfort to breaking down the joint over time (osteoarthritis is one type of degenerative arthritis).
What are the symptoms of carpal tunnel syndrome?
Symptoms usually begin slowly and can occur at any time. Early symptoms include:
- Numbness at night.
- Tingling and/or pain in the fingers (especially the thumb, index and middle fingers).
In fact, because some people sleep with their wrists curled, nighttime symptoms are common and can wake people from sleep. These nighttime symptoms are often the first reported symptoms. Shaking the hands helps relieve symptoms in the early stage of the condition.
Common daytime symptoms can include:
- Tingling in the fingers.
- Decreased feeling in the fingertips.
- Difficulty using the hand for small tasks, like:
- Handling small objects.
- Grasping a steering wheel to drive.
- Holding a book to read.
- Using a computer keyboard.
As carpal tunnel syndrome worsens, symptoms become more constant. These symptoms can include:
- Weakness in the hand.
- Inability to perform tasks that require delicate motions (such as buttoning a shirt).
- Dropping objects.
In the most severe condition, the muscles at the base of the thumb visibly shrink in size (atrophy).
Diagnosis and Tests
How is carpal tunnel syndrome diagnosed?
First, your doctor will discuss your symptoms, medical history and examine you. Next, tests are performed, which may include:
- Tinel’s sign: In this test, the physician taps over the median nerve at the wrist to see if it produces a tingling sensation in the fingers.
- Wrist flexion test (or Phalen test): In this test, the patient rests his or her elbows on a table and allows the wrist to fall forward freely. Individuals with carpal tunnel syndrome will experience numbness and tingling in the fingers within 60 seconds. The more quickly symptoms appear, the more severe the carpal tunnel syndrome.
- X-rays: X-rays of the wrist may be ordered if there is limited wrist motion, or evidence of arthritis or trauma.
- Electromyography (EMG) and nerve conduction studies: These studies determine how well the median nerve itself is working and how well it controls muscle movement.
Management and Treatment
How is carpal tunnel syndrome treated?
Carpal tunnel syndrome can be treated in two ways: non-surgically or with surgery. There are pros and cons to both approaches. Typically, non-surgical treatments are used for less severe cases and allow you to continue with daily activities without interruption. Surgical treatments can help in more severe cases and have very positive outcomes.
Non-surgical treatments are usually tried first. Treatment begins by:
- Wearing a wrist splint at night.
- Taking nonsteroidal anti-inflammatory drugs, such as ibuprofen.
- Cortisone injections.
Other treatments focus on ways to change your environment to decrease symptoms. This is often seen in the workplace, where you can make modifications to help with carpal tunnel. These changes might include:
- Raising or lowering your chair.
- Moving your computer keyboard.
- Changing your hand/wrist position while doing activities.
- Using recommended splints, exercises and heat treatments from a hand therapist.
Surgery is recommended when carpal tunnel syndrome does not respond to non-surgical treatments or has already become severe. The goal of surgery is to increase the size of the tunnel in order to decrease the pressure on the nerves and tendons that pass through the space. This is done by cutting (releasing) the ligament that covers the carpal tunnel at the base of the palm. This ligament is called the transverse carpal ligament.
If you have surgery, you can expect to:
- Have an outpatient procedure where you will be awake, but have local anesthesia (pain numbing medication). In some cases, your doctor may offer an IV (directly into the vein) anesthetic. This option allows you to take a brief nap and wake up after the procedure is finished. This is not a general anesthetic, like what is used in surgery. Instead, your healthcare team will monitor you during the procedure (called monitored anesthetic care, or MAC). This is also used for procedures like a colonoscopy.
- Be in brief discomfort for about 24 to 72 hours after surgery. People usually experience complete nighttime symptom relief quickly—even the night after surgery.
- Have your stitches removed 10 to 14 days after surgery. Hand and wrist use for everyday activities is gradually restored by using specific exercise programs.
- Be unable to do heavier activities with the affected hand for about four to six weeks. Recovery times can vary depending on your age, general health, severity of carpal tunnel syndrome and how long you had symptoms. You will continue to gain strength and sensation in the following year after surgery.
- Have relief from most carpal tunnel syndrome symptoms.
How can carpal tunnel syndrome be prevented?
Carpal tunnel syndrome can be difficult to prevent. The condition can be caused by so many different activities in a person’s daily life that prevention can be challenging. Workstation changes—proper seating, hand and wrist placement—can help decrease some factors that can lead to carpal tunnel syndrome. Other preventative methods include:
- Sleeping with your wrists held straight.
- Keeping your wrists straight when using tools.
- Avoiding flexing (curling) and extending your wrists repeatedly.
- Decreasing repetitive/strong grasping with the wrist in a flexed position.
- Taking frequent rest breaks from repetitive activities.
- Performing conditioning and stretching exercises before and after activities.
- Monitoring and properly treating medical conditions linked to carpal tunnel syndrome.
Outlook / Prognosis
Does carpal tunnel syndrome have a long recovery?
Surgery to repair carpal tunnel syndrome does not have a particularly long recovery. The bandage that covers the stitches after surgery can be removed in a few days. The hand can then be used for light activities. Making a fist is encouraged. Full range of finger motion and early symptom relief is usually seen within two weeks after the stitches have been removed. You can usually return to most activities by six weeks. Your return to work depends on factors such as type of work, how much control you have over your work and workplace equipment.
What is the success rate for carpal tunnel syndrome surgery?
Surgery for carpal tunnel syndrome has a very high success rate of over 90%. Many symptoms are relieved quickly after treatment, including tingling sensation in the hands and waking up at night. Numbness may take longer to be relieved, even up to three months. Surgery won’t help if carpal tunnel syndrome is the wrong diagnosis.
When the carpal tunnel syndrome has become severe, relief may not be complete. There may be some pain in the palm around the incisions that can last up to a few months. Other after-surgery pain may not be related to carpal tunnel syndrome. Patients who complain of pain or whose symptoms remain unchanged after surgery either had severe carpal tunnel syndrome, had a nerve that was not completely released during surgery, or did not really have carpal tunnel syndrome. Only a small percentage of patients do not gain substantial relief from symptoms.