Carpal tunnel syndrome is a common condition affecting the hand and arm and causes pain, numbness, and tingling. It occurs when one of the major nerves supplying to the hand — the median nerve — is squeezed or compressed.
In most patients, carpal tunnel syndrome worsens over time, and thus, early diagnosis and treatment are crucial. In early stages, symptoms can often be relieved with simple measures like wearing a wrist splint or avoiding certain activities.
But, if the pressure on the nerve continues, it can lead to nerve damage and worsening symptoms. To prevent permanent damage, surgery may be recommended to take the pressure off the median nerve for some patients.
Carpal Tunnel Anatomy
Carpal tunnel is a narrow passageway in the wrist, about an inch wide, floor and sides of which are formed by small wrist bones called carpal bones. The carpal tunnel protects the median nerve and flexor tendons that allow bending of the fingers and thumb.
The roof of the tunnel is a strong and rigid band of connective tissue called the transverse carpal ligament, and given its rigidity, the carpal tunnel has little capacity to “move or stretch” or increase in size.
The median nerve is a major nerve in the hand. It originates in the neck and travels down the arm and forearm, passes through the carpal tunnel in the wrist, and enters into the hand. The nerve provides sensations/ feeling in the thumb and index, middle, and ring fingers. It also controls the muscles around the base of the thumb.
The nine flexor tendons that bend the fingers and thumb also travel through the carpal tunnel.
Carpal tunnel syndrome is caused when the tunnel becomes narrowed or when tissues surrounding the flexor tendons get swollen, putting pressure on the median nerve. These surrounding tissues are called ‘synovium’. Normally, the synovium lubricates the tendons, making it easier to move the fingers.
When the synovium swells, it occupies space in the carpal tunnel and, over a period of time, puts a pressure on the nerve. This abnormal pressure on the nerve can result in pain, numbness, tingling, and weakness in the hand.
Most cases are caused by a combination of factors. Studies show that women and older people are more prone to carpal tunnel syndrome.
Other risk factors include:
· Heredity-This is likely an important factor. The traits of having a small or an anatomically different carpal tunnel may run in families.
· Repetitive hand use-Repeating the same hand and wrist motions over a prolonged duration may aggravate the tendons in the wrist; causing swelling that then puts pressure on the nerve.
· Hand and wrist position-Doing activities that involve extreme flexion or extension of the hand and wrist repeatedly can increase pressure on the nerve.
· Pregnancy-Hormonal changes during pregnancy may cause swelling.
· Health conditions- Diabetes, rheumatoid arthritis, and thyroid gland imbalances are conditions that are associated with carpal tunnel syndrome.
· Symptoms of carpal tunnel syndrome may include:
· Numbness, tingling, burning, and pain—mainly in the thumb and index, middle, and ring fingers
· Occasional shock-like feelings to the thumb and radiating to index, middle, and ring fingers
· Pain or tingling that may even move up the forearm toward the shoulder
· Weakness and clumsiness in the hand—this at times, may make it difficult to perform fine movements such as buttoning your clothes
· Dropping things—due to weakness, numbness, or a loss of proprioception-awareness of where your hand is in space
In most cases, symptoms begin gradually—without a specific injury. In early days, the symptoms come and go at first, but, as the condition worsens, symptoms may occur more frequently or may persist for longer periods of time.
Night-time symptoms are common because many people sleep with their wrists bent. Such symptoms may awaken you from sleep. During the day, symptoms generally occur when holding something for a prolonged period of time with the wrist bent such as when using a phone, driving, or reading a book.
Many patients find moving or shaking their hands help relieve their symptoms.
During your evaluation, your doctor will-
Speak to you about your general health and medical history and will ask about your symptoms.
Will carefully examine your hand and wrist and perform a number of physical tests.
During these tests, your doctor will:
Press down or tap along the median nerve at inside of your wrist to see if it causes any numbness or tingling in your fingers (Tinel sign)
Bend and hold your wrists in a flexed position to test for numbness or tingling in your hands
Test sensitivity in your fingertips and hands by lightly touching them with a special instrument when your eyes are closed.
Check for weakness in the muscles around the base of your thumb
Look for atrophy in the muscles around the base of your thumb. In severe cases, these muscles may become smaller.
For Tinel’s test for nerve damage, your doctor will tap on the inside of your wrist over the median nerve.
Reproduced from JF Sarwark, ed: Essentials of Musculoskeletal Care, ed 4. Rosemont, IL, American Academy of Orthopaedic Surgeons, 2010.
Electrophysiological tests- These tests allow to measure how well your median nerve is working and whether there is too much pressure on the nerve. The tests will also help your doctor identify any other nerve condition, such as neuropathy, or other sites of nerve compression that might be contributing to your symptoms.
Electrophysiological tests may include:
· Tests for nerve conduction. These tests measure the signals travelling in the nerves of your hand and arm and can detect when a nerve is not conducting its signal effectively. Nerve conduction studies can help your doctor determine how severe your problem is and help to guide treatment.
· Electromyogram (EMG)- An EMG measures the electrical activity in muscles. EMG results can show whether you have any nerve or muscle damage.
Ultrasound– Your doctor may recommend an ultrasound of your wrist to evaluate the median nerve for signs of compression that uses high-frequency sound waves to help create pictures of bone and tissue.
X-rays– X-rays are helpful to provide images of dense structures, such as bones. If you have limited wrist motion or wrist pain, your doctor may order x-rays to exclude other causes for your symptoms, such as arthritis, ligament injury, or a fracture.
Magnetic resonance imaging (MRI) scans– These studies provide images of the body’s soft tissues. Your doctor may order an MRI to help determine other causes for your symptoms or to look for any abnormal tissues that could be impacting the median nerve. An MRI can also help your doctor in determining if there are problems with the nerve itself—such as scarring from an injury or a tumor.
Carpal tunnel syndrome generally worsens over time without any form of treatment. For this reason, it is important to get evaluated and diagnosed by your doctor early on. In early stages, it may be possible to slow down or stop the progression of the disease.
If diagnosed early, the symptoms of carpal tunnel syndrome can often be relieved without the need of a surgery. If your diagnosis is uncertain or if your symptoms are mild, your doctor will at first recommend nonsurgical treatment. That may include-
Splinting– Wearing a splint at night will keep you from bending your wrist while you sleep. Keeping your wrist straight or in a neutral position reduces pressure on the nerve in the carpal tunnel. It may also help to wear a splint during the day when doing activities that aggravate your symptoms. Wearing a splint or brace helps reduce pressure on the median nerve by keeping your wrist straight.
Nonsteroidal anti-inflammatory drugs (NSAIDs)- Medications that are anti-inflammatory and analgesics (pain killers) help relieve wrist pain.
Change in activity– Symptoms often occur when your hand and wrist are in the same position for too long—particularly if they are flexed or extended. Changing or modifying these activities can help slow or stop the progression. In some cases, this may even involve making changes to your work site or work station.
Nerve gliding exercises– Some patients may benefit from exercises that help the median nerve move more freely within the carpal tunnel. Specific exercises may be recommended by your doctor or physiotherapist.
Steroid injections– although these injections often relieve painful symptoms or help to calm a flare up of symptoms, their effect sometimes is only temporary. A steroid (cortisone) injection may also be used by your doctor to help confirm the diagnosis of carpal tunnel syndrome.
If nonsurgical treatment(s) does not relieve your symptoms after a period of time, your doctor may recommend you to undergo surgery.
The decision whether to undergo surgery or not is based on the severity of your symptoms—how much pain and numbness you are having in your hand. In long-standing cases with constant numbness and wasting of your thumb muscles, surgery may be recommended to prevent irreversible damage.
The surgical procedure performed is called a “carpal tunnel release”, the goal is to relieve pressure on your median nerve by cutting the ligament that forms the roof of the tunnel. This increases the size of the tunnel and decreases pressure on the median nerve.
In most cases, this surgery is done on an outpatient basis. The surgery can be done under general anesthesia (GA) which puts you to sleep, or under local anesthesia (LA) which just numbs your hand and arm. In some cases, you will be given a light sedative through an intravenous (IV) line inserted into a vein in your arm.
Open surgery for carpal tunnel release– In open surgery, your doctor makes a small incision in the palm of your hand and views the inside of your hand and wrist through this incision. Your doctor will then divide the transverse carpal ligament. This increases the size of the tunnel and decreases pressure on the median nerve.
Endoscopically performed carpal tunnel release– In endoscopic surgery, your doctor makes one or two small skin incisions—called portals—and uses a miniature camera—an endoscope—to see inside your hand and wrist. A special knife is used to divide the transverse carpal ligament, similar to the open carpal tunnel release procedure.
Immediately following surgery, you will be instructed to elevate your hand above your heart and move your fingers periodically to reduce swelling and prevent stiffness. You may experience some pain, swelling, and stiffness after your procedure. Minor soreness in your palm may last for several weeks to several months.
Strength to grip and pinch usually return by about 2 to 3 months after surgery. If the condition of your median nerve was poor before surgery, it may take about 6 to 12 months for the strength to return.
You may have to wear a splint or wrist brace for several weeks. You will be allowed to use your hand for light activities, taking care to avoid significant discomfort. Driving, self-care activities, and light lifting and gripping may be allowed soon after surgery.
Your doctor will talk with you about when you will be able to return back to work and whether you will have any restrictions on your work activities.
Complications are a possibility with any surgery, and your doctor will take steps to minimize the risks. The most common complications of carpal tunnel release surgery include:
Ø Nerve aggravation or injury
For most patients, surgery improves the symptoms of carpal tunnel syndrome. Complete recovery, however, may be gradual and may take up to a year.
If you have significant pain and weakness for more than 2 months, your doctor may refer you to a hand therapist who can help you maximize your recovery.
If you have another condition that causes pain or stiffness in your hand or wrist, such as arthritis or tendonitis, it may slow your overall recovery. In long-standing cases with severe loss of sensation and/or muscle wasting around the base of the thumb, recovery will be slower. For these patients, a complete recovery may not be possible.
Occasionally, carpal tunnel syndrome can recur, although this is rare. If this happens, you may need additional treatment or surgery.