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In This Report

•	Highlights
•	Introduction
•	Symptoms
•	Causes
•	Risk Factors
•	Prognosis
•	Prevention
•	Diagnosis
•	Treatment
•	Surgery
•	Resources
•	References

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•	Carpal tunnel syndrome
•	Distal median nerve dysfunc...
•	Carpal tunnel release

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Carpal Tunnel Syndrome

Highlights

Treatment News:

• A recent study showed that wearing a 5% lidocaine patch every day relieved pain at least as well as an injection with combination lidocaine-steroids.
• Patients who get two steroid injections 8 weeks apart do not benefit from the second injection, according to a study published in the International Journal of Clinical Practice.  The trial compared the benefits of two steroid injections to a single injection.
• A recently published review of patients who had endoscopic release procedures for carpal tunnel syndrome (CTS) questions the widely held belief that endoscopy carries a higher risk of complications. The analysis revealed very few complications. Ninety percent of the patients returned to their original line of work.
• A recent study published in the Journal of Hand Surgery found that patients with CTS who have the mini-open surgery recover faster than those who have traditional open release surgery. Mini-open surgery is less invasive than open release surgery.

Risk factors:

• Weight appears to be strongly linked to the onset of CTS, although it may be less of a risk factor in older people.
• A 2005 study reported that an estimated 85% of patients with type 1 diabetes develop CTS.

Introduction

Carpal tunnel syndrome (CTS) is a disorder marked by weakness and pain in the hand and wrist. CTS occurs in the nerves of the hands -- not the muscles, as some people believe. The symptoms of CTS can be incapacitating.

The Carpal Tunnel and Median Nerve

To understand how carpal tunnel syndrome arises, it is important to know the parts of the hand and wrist that are involved.

The Carpal Tunnel. The carpal tunnel is a passageway that forms beneath the strong, broad transverse ligament. This ligament is a bridge that extends across the lower palm and connects the bones of the wrist (carpals), which form an arch below the tunnel.

The Median Nerve and Flexor Tendons. The median nerve and nine flexor tendons pass under the ligament bridge and through the carpal tunnel (similar to a river). They extend from the forearm and up into the hand:

• The flexor tendons are fibrous cords that connect to muscles of the fingers (two to each finger) and one to the thumb. They allow flexing of the fingers and clenching of the fist.
• The median nerve plays two important roles. It supplies sensation to the thumb, index, middle, and ring fingers, and to the flexor tendons. It provides function for the muscles at the base of the thumb (the thenar muscle).

The median nerve travels through a compartment in the wrist called the carpal tunnel. The ligaments that transverse the nerve are not very flexible. Any swelling within the wrist compartment can put excessive pressure on structures such as the blood vessels and the median nerve. Excessive pressure can constrict blood flow and cause nerve damage. The symptoms from the compression cause pain, loss of sensation, and decreased function in the hand.

The Carpal Tunnel Syndrome Process

It is not completely known how the process leading to carpal tunnel syndrome actually evolves, and how nerve conduction (the passing of the nerve signal) through the wrist becomes changed. In general, carpal tunnel syndrome develops when the tissues around the median nerve swell and press on the nerve. Early in the disorder, the process is reversible. Over time, however, the insulation on the nerves may wear away, and permanent nerve damage may develop.

The following events have been observed in the hands of people with carpal tunnel syndrome:

• The protective lining of tendons (called the tenosynovium) swells within the carpal tunnel. Some research suggests that this swelling is caused by build-up of fluid (called synovial fluid) under the lining. Synovial fluid lubricates and protects the tendons.
• The transverse ligament, the band of fibrous tissue that forms the roof over the median nerve, becomes thicker and broader.
• The swollen tendons and thickened ligament compress the median nerve fibers, just as stepping on a hose slows the flow of water through it. The effect is to reduce blood flow and oxygen supply to the nerve, slowing the transmission of nerve signals through the carpal tunnel. Some cases of carpal tunnel syndrome may be due to enlargement of the median nerve rather than compression by surrounding tissues.

The result is pain, numbness, and tingling in the wrist, hand, and fingers. Only the little finger is unaffected by the median nerve.

Click the icon to see a depiction of carpal tunnel syndrome.

Symptoms

Symptoms of carpal tunnel syndrome usually progress gradually over weeks and months and sometimes years. Anyone with recurrent or persistent pain, numbness and tingling, or weakness of the hand should consult a doctor for a diagnosis. Symptoms often develop as follows:

• Initial symptoms include pain in the wrist and hand. Symptoms commonly occur in both hands. (Even when only one hand is painful, the other hand often shows signs of nerve conduction abnormalities on testing.)
• Early on, the patient also usually reports numbness, tingling, burning, or some combination on the palm side of the index, middle, and ring fingers. (Typically the fifth finger has no symptoms.) Such sensations may radiate to the forearm or shoulder.
• Over time, the hand may become numb, and patients may lose the ability to feel heat and cold. Patients may experience a sense of weakness and a tendency to drop things.
• Patients may feel that their hands are swollen even though there is no visible swelling. This symptom may actually prove to be an important indicator of greater severity.

Symptoms may occur not only when the hand is being used but also at night when the patient is at rest. Even in cases where work is suspected as the cause, symptoms typically first occur outside of work. In fact, the disorder may be distinguished from similar conditions by pain occurring at night after going to bed.

Causes

Biologic Causes. Carpal tunnel syndrome (CTS) is considered an inflammatory disorder caused by repetitive stress, physical injury, or medical conditions. It is often very difficult, however, to determine the precise cause of carpal tunnel syndrome. No tests are available to identify a specific cause. Except in patients with certain underlying diseases, the biologic mechanisms leading to carpal tunnel syndrome are unknown. Although an overactive immune response that causes inflammation and damage in the joints or muscles is responsible for a number of arthritic conditions, similar problems are not likely to play an important role in CTS. More likely, reduced blood flow and lack of oxygen are important in the process leading to progressive swelling and scarring.

Working Conditions versus Medical Problems. Although some studies suggest that more than half of CTS cases are associated with workplace factors, there is no strong evidence of a cause and effect relationship. In fact, most studies now strongly suggest that carpal tunnel syndrome is primarily associated with medical or physical conditions such as diabetes, osteoarthritis, hypothyroidism, and rheumatoid arthritis. CTS also tends to occur in people with certain genetic or environmental risk factors such as obesity, smoking, alcohol abuse, or significant mental stress. When such susceptible people are subjected to repetitive hand or wrist work, the risk for CTS can become significant. CTS, then, is very likely to be due to convergences of factors that lead to nerve damage in the hand.

Work-Related Issues and Carpal Tunnel Syndrome

Worker's Compensation and CTS. The issues surrounding workers' compensation are particularly troubling in determining accurately whether labor conditions cause carpal tunnel pain. CTS is a major contributor to workers' compensation cases.

High Force and Vibration. Even though medical and physical conditions may be the initial culprits leading to CTS, certain working conditions are especially related to nerve damage -- if not to pure cases of CTS. Work that involves high force or vibration is particularly hazardous, as is repetitive hand and wrist work in cold temperatures.

In addition to CTS, other disorders of hand and wrist result from these work-related movements. They include the following:

• Hand-arm vibration syndrome -- tingling and numbing that persist even after the vibration stops 
• Cumulative trauma (repetitive stress) disorder
• Overuse syndromes
• Chronic upper limb pain syndrome

All of these problems are generally associated with repetitive and forceful use of the hands, resulting in damaged muscles and bones of the upper arms.

Psychosocial Factors in the Workplace. Studies indicate that psychosocial factors in the workplace, such as intense deadlines, a poor social work environment, and low levels of job satisfaction, are major contributors to carpal tunnel pain. Such psychosocial conditions are more likely to be important factors in contributing to CTS in office workers, although they also complicate the condition in workers whose work is primarily physical.

Medical Conditions

A number of medical conditions increase the risk for or even cause CTS. The main conditions associated with CTS are diabetes, hypothyroidism, rheumatoid arthritis, osteoarthritis, obesity, and pregnancy. Many of the underlying diseases that contribute to the development of CTS are also associated with more severe forms of CTS.

Diabetes. CTS is a very common feature of diabetic neuropathy, one of the major complications of diabetes. Neuropathy is decreased or distorted nerve function; it particularly affects sensation. Symptoms include numbness, tingling, weakness, and burning sensations, usually starting in the fingers and toes and moving up to the arms and legs. About 6% of patients with CTS have diabetes. A 2005 study reported that an estimated 85% of patients with type 1 diabetes develop CTS. Development of CTS was related to the patient's age and the length of time they had diabetes. The development of diabetes-related complications, such as kidney disease, is not related to the development of CTS in people with diabetes.

Autoimmune Diseases. In autoimmune diseases, the body's immune system abnormally attacks its own tissue, causing widespread inflammation, which, in many cases, affects the carpal tunnel of the hand. Such autoimmune diseases include rheumatoid arthritis, systemic lupus erythematosus, and hypothyroidism. Some experts believe that CTS may actually be one of the first symptoms in a number of these diseases. Studies also suggest that CTS patients with these disorders are more likely to have severe CTS that requires surgery.

Diseases that Affect Muscle and Bones. Arthritis, gout, and other medical conditions that damage the muscles, joints, or bones in the hand may cause changes that lead to CTS. In fact, in one 2000 study, susceptibility to muscle and bone diseases was the major risk factor for CTS in British women. Osteoporosis (loss of bone density), although not a direct cause of CTS, increases the risk for wrist fractures that can lead to CTS.

Injuries and Previous Surgeries. Injuries, fractures, and operations that affect the forearm, wrist, or hand may lead to CTS, sometimes many years after the event.

Structural Abnormalities. Inborn abnormalities in the bones of the hand, wrist, or forearm may contribute to CTS.

Chronic Kidney Insufficiency. People who undergo hemodialysis for chronic kidney damage often experience a build-up in the hand of a certain type of protein called beta 2-microglobulin. This build-up can result in CTS. The longer the person has been receiving hemodialysis, the greater the risk of CTS. Certain drugs and procedures (particularly one procedure called hemodiafiltration) are being investigated as having the potential to reduce microglobulin build-up. It is hoped such new methods will delay the need for carpal tunnel surgery in patients undergoing long-term hemodialysis.

Other Diseases. A number of other medical conditions may cause or increase susceptibility to CTS:

• Down syndrome
• Amyloidosis (a progressive disorder of the connective tissues)
• Acromegaly (a disease that leads to abnormally large hands and feet due to excessive growth hormone)
• Tumor on the median nerve (removal of the tumor often resolves the CTS in such cases)

Medications. According to case reports, a number of medications may increase the risk for temporary CTS. They include certain medications that affect the immune system (such as interleukin-2), and anticlotting drugs (such as warfarin). There has been conflicting evidence as to whether corticosteroids and hormone replacement therapy may increase risk. More research is warranted before a causal association can be established.

Injuries

Bone dislocations and fractures can narrow the carpal tunnel, thereby exerting pressure on the median nerve.

Obesity and Lack of Fitness

Being overweight consistently turns up as a risk factor for CTS and may play a direct causal role on CTS. Greater body mass appears to reduce nerve flow speed into the hand. Obesity is also related to poor physical fitness, which may also increase risk. A 2005 analysis indicated that weight is strongly linked to the onset of CTS in patients under the age of 63 years, but may be a less important factor as they get older.

Hormonal Changes

Hormonal fluctuations in women play a role in CTS. Such fluctuations may cause fluid retention and other changes in the body that cause swelling. Fluid retention is one reason that CTS may develop during pregnancy.

Genetic Factors

CTS is strongly associated with a family history of the disorder. Many of these cases can be attributed to physical characteristics or medical conditions associated with CTS, which also run in families. However, in one study, 17% of family clusters of CTS were not associated with any such medical conditions, suggesting the genetic factors may be important in some people. Carpal tunnel syndrome that develops in young people is most likely to have a genetic component.

A 2000 study suggested that some patients with CTS may have a genetic defect that produces higher levels of a certain collagen subtype. Collagen is the protein used to build all connective tissue, muscle, bones, and ligament. The collagen found in CTS patients tends to produce stiffness.

Other genetic factors that may contribute to this disorder include abnormalities in certain genes that regulate myelin, a fatty substance that serves as insulation for nerve fibers.

Risk Factors

Evidence suggests that about 3% of women and 2% of men will be diagnosed with carpal tunnel syndrome during their lifetimes, with peak prevalence in women older than 55. Still, determining how many people actually have CTS is very difficult. Many people report CTS symptoms and have normal test results. Other people have no symptoms and abnormal results. Furthermore, some evidence suggests that, after an apparent a decline in cases, the prevalence of CTS is rising.

A large 2005 study of more than 1,000 patients found that the severity of CTS was mild in 42% of patients, moderate in 18%, and severe in 40%. Patients were an average of about 48 years old. More than five times as many women then men participated in the study.

Age

Older people are at higher risk than younger adults. It is very rare in children.

Women

Many studies indicate that women have a significantly higher risk for carpal tunnel syndrome than men do. According to the National Institutes of Health, women are three times more likely than men to experience carpal tunnel syndrome. The explanation for this greater risk is unknown but may be related to the smaller size of women's carpal tunnel.

Hormonal changes appear to play a major role in CTS.

A 2005 study reported that 17% of pregnant women had CTS. Nearly one-quarter of those had it in both wrists. Early studies have presented conflicting reports regarding when CTS is most likely to occur during pregnancy. One found that most cases occurred in the third trimester, and weight gain increased the risk. Another concluded that CTS developed at any point during the pregnancy. New-onset CTS during pregnancy that is severe and persistent enough to require treatment is uncommon. Most cases go away on their own after delivery. However, in one study, 11% of women reported CTS six months after delivery, and 4.3% of them still had the condition a year afterward.

Breastfeeding has also been linked to flare-ups of inflammatory disorders such as CTS. Breastfeeding temporarily lowers the level of natural steroid hormones.

CTS has also been shown to increase during:

• The postpartum period
• Menopause

Other conditions that are more specific to women than men may increase their risk for carpal tunnel syndrome:

• The hand-intensive nature of housework and typing may contribute to a higher incidence of CTS in women.
• Women are also at a much higher risk for autoimmune disorders than men are; such disorders are significantly linked to CTS.

Family History

People with close relatives who have carpal tunnel syndrome have a higher risk of developing CTS themselves. This risk may be due to family histories of medical conditions associated with CTS, obesity, or genetic factors.

People with Underlying Medical Conditions

A number of illnesses, skeletal abnormalities, and injuries can predispose individuals to carpal tunnel syndrome, including autoimmune diseases and arthritic conditions.

Workers at High Risk

At high risk are those whose occupations combine force and repetition of the same motion in the fingers and hand for long periods.

Other Physical Characteristics

Square Wrists. Some (but not all) studies have reported a higher risk for CTS in people with square wrists (the thickness and width are about the same) than in those with the more common rectangular wrists.

Palm Shape. In one study, patients with palms that were both shorter and wider than average, and who also had shorter third fingers, were more likely to have CTS than those without these hand characteristics.

Poor Upper Back Strength. Some researchers claim that poor upper back strength makes people more susceptible to poor posture and injuries in the upper extremities, including carpal tunnel syndrome.

Smoking and Alcohol Abuse

Cigarette smoking slows down blood flow, so that smokers have worse symptoms and slower recovery than nonsmokers do. Increased alcohol intake has been associated with CTS in people with other risk factors.

Other Factors

Poor nutrition, previous injuries, and stress can increase one's risk for carpal tunnel syndrome. In addition, high levels of so-called “bad” cholesterol (low-density lipoprotein, or LDL) have also been linked to an increased risk of CTS.

Prognosis

Carpal tunnel syndrome can range from a minor inconvenience to a disabling condition, depending on its cause and persistence and the individual characteristics of the patient. Many cases of CTS are mild, and when symptoms are of short duration, they often resolve (disappear) on their own. Once a woman with pregnancy-associated CTS gives birth, for instance, the swelling in her wrists and other symptoms almost always subside. Proper treatment of other medical conditions that cause CTS can often help reduce wrist swelling.

In severe untreated cases, however, the thenar muscles at the base of the thumb may whither, and loss of sensation may be permanent. CTS can become so crippling that people can no longer do their jobs or even perform simple tasks at home.

Psychological and Social Effects at Home

Carpal tunnel syndrome exacts a psychological toll. Anyone who cannot use his or her hands is likely to be depressed and suffer from low self-esteem. People may suffer from daily pain. In severe cases, they may be unable to perform ordinary tasks, such as driving a car or carrying groceries. And equally or even more distressing, they may have to give up enjoyable sports and hobbies.

Impact on Work and Livelihood

According to a 2005 report from the Bureau of Labor Statistics, among the major disabling diseases and illnesses, carpal tunnel syndrome was associated with the longest average time away from work (28 days).

Employees with CTS who try to work through the disorder often put more stress on the wrists to compensate for the weakness and pain. The end result is to make the condition worse and impair work performance.

Eventually, the worker with CTS may be forced to give up his or her livelihood. In one study, nearly half of all patients with CTS changed jobs within 30 months of an initial diagnosis. And because of the controversy surrounding the issue of carpal tunnel syndrome and workers compensation, it is not always certain that the worker will receive compensation payments.

Prevention

Because multiple factors may cause carpal tunnel syndrome, there is no single mode of prevention. Treating any underlying medical condition is certainly important. Simple common sense may help minimize some risk factors predisposing a person to work-related CTS or other cumulative trauma disorders. A patient can learn how to adjust the work area, handle tools, or perform tasks in ways that put less stress on the hands and wrists. Proper posture and exercise programs to strengthen the fingers, hands, wrists, forearms, shoulders, and neck may help prevent CTS.

Corporate Efforts

Many companies are now taking action to help prevent repetitive stress injuries. In a major survey, 84% reported that they were modifying equipment, tasks, and processes. Nearly 85% were analyzing their workstations and jobs, and 79% were buying new equipment. It should be stressed, however, that there has been no evidence that any of these methods can provide complete protection against CTS. The optimal corporate approach, if possible, is to reallocate workers suffering from repetitive stress injuries to other jobs.

Preventing CTS in Keyboard Workers

Altering the way a person performs repetitive activities may help prevent inflammation in the hand and wrist from progressing into carpal tunnel syndrome. For example, replacing old tools with ergonomically designed new ones can be very helpful.

Rest Periods and Avoiding Repetition. Anyone who does repetitive tasks should begin with a short warm-up period, take frequent breaks, and avoid overexertion of the hand and finger muscles whenever possible. Employers should be urged to vary tasks and work content.

A 2001 study conducted by the National Institute for Occupational Safety and Health reported that even taking multiple "microbreaks" (about 3 minutes each) reduces strain and discomfort without decreasing productivity. Such breaks may include the following:

• Shaking or stretching the limbs
• Leaning back in the chair
• Squeezing the shoulder blades together.
• Taking deep breaths

Good Posture. Good posture is extremely important in preventing carpal tunnel syndrome, particularly for typists and computer users.

• The worker should sit with the spine against the back of the chair with the shoulders relaxed.
• The elbows should rest along the sides of the body, with wrists straight.
• The feet should be firmly on the floor or on a footrest.
• Typing materials should be at eye level so that the neck does not bend over the work.
• Keeping the neck flexible and head upright maintains circulation and nerve function to the arms and hands. One method for finding the correct head position is the "pigeon" movement. Keeping the chin level, glide the head slowly and gently forward and backward in small movements, avoiding neck discomfort.

Good Office Furniture. Poorly designed office furniture is a major contributor to bad posture. Chairs should be adjustable for height, with a supportive backrest. Custom-designed chairs, made for people who do not fit in standard chairs, can be expensive. However, the costs are often offset by the savings in medical expenses that follow injuries related to bad posture.

Voice Recognition Software. For CTS patients who must use a computer frequently, a variety of voice recognition software packages (ViaVoice, Voice Xpress, Dragon NaturallySpeaking, IListen) are now available, enabling virtually hands-free computer use.

Keyboard and Mouse Tips. Anyone using a keyboard and mouse has some options that may help protect the hands.

• The tension of the keys should be adjusted so they can be depressed without excessive force.
• The hands and wrists should remain in a relaxed position to avoid excessive force on the keyboard.
• A 2003 study suggested that mouse-use poses a higher risk than keyboard use. Replacing the mouse with a trackball device and the standard keyboard with a jointed-type keyboard are helpful substitutions.
• Wrist rests, which fit under most keyboards, can help keep the wrists and fingers in a comfortable position.
• Some people recommend keeping the computer mouse as close to the keyboard and the user's body as possible, to reduce shoulder muscle movement.
• The mouse should be held lightly, with the wrist and forearm relaxed. New mouse supports (ErgoCat) are also available that relieve stress on the hand and support the wrist.
• Some people cut their mouse pads in half to reduce movement.

Innovative keyboard designs may reduce hand stress:

• Alternative geometry keyboards (Microsoft Natural Keyboard, Apple Adjustable Keyboard) allow the user to adjust and modify hand positions as well as adjust key tension. Most have a split or "slanted" keyboard that places the wrists at an angle. Studies suggest they are useful in promoting a neutral position for the wrist.
• The continuous passive motion (CPM) keyboard lifts and declines gently and automatically every three minutes to break tension on the hands and wrist. A report of a clerical worker with CTS who used this device found an overall improvement of 10 words per minute in the typing tests, a decrease in disability score and symptom severity, and an improvement in function.
• A keyless keyboard (orbiTouch) is an innovative device that uses two domes. The typist covers the domes with his or her hands and slides them into different positions that represent letters.

Reducing Force from Hand Tools

The force placed on the fingers, hands, and wrists by a repetitive task is an important contributor to CTS. To alleviate the effect of force on the wrist, tools and tasks should be designed so that the wrist position is the same as it would be if the arms dangled in a relaxed manner at the sides.

• No task should require the wrist to deviate from side to side or to remain flexed or highly extended for long periods.
• The handles of hand tools such as screwdrivers, scrapers, paint brushes, and buffers should be designed so that the force of the worker's grip is distributed across the muscle between the base of the thumb and the little finger, not just in the center of the palm.
• People who need to hold any tools (including pencils and steering wheels) for long periods of time should grip them as loosely as possible.
• In order to apply force appropriately, the ability to feel an object is extremely important. Tools with textured handles are helpful.
• If possible, people should avoid working at low temperatures, which reduces sensation in hands and fingers.
• Power tools and machines should be designed to minimize vibrations.
• Wearing thick gloves, when possible, may lessen the shock transmitted to the hands and wrists. One 2001 study found, however, that wearing gel-padded gloves clearly increased comfort but did not actually protect against compression-induced CTS.

Hand and Wrist Exercises for Prevention of Carpal Tunnel Syndrome

Hand and wrist exercises may help reduce the risk of developing carpal tunnel syndrome. Isometric and stretching exercises can strengthen the muscles in the wrists and hands, as well as the neck and shoulders, improving blood flow to these areas. Performing the simple exercises described below for 4 to 5 minutes every hour may be helpful.

Diagnosis

Carpal tunnel syndrome (CTS) is most accurately diagnosed using the patients' descriptions of symptoms, and electrodiagnostic tests that measure nerve conduction through the hand. If electrodiagnostic testing is not available, then symptom descriptions and a series of physical tests are useful.

Diagnosing CTS, however, is not straightforward. Only a small fraction of patients exhibit all three factors necessary for a clear diagnosis:

• Classic CTS symptoms
• Specific physical findings
• Abnormal electrodiagnostic test results

Many people have abnormal electrodiagnostic test results without classic symptoms or any symptoms at all. Furthermore, about 15% of the population has symptoms consistent with CTS, but most do not show test results indicating the disorder. In fact, in a 2001 study, some patients who had symptoms, but whose nerve and physical tests were normal, still experienced relief after CTS surgery.

Symptom Description and Severity

Many cases of CTS are a combination of a medical problem exacerbated by repetitive stress factors at work. The patient should give the doctor a detailed history and description of any complaints, in any part of the body. The patient should report in detail any daily activities that require repetitive hand or wrist actions, abnormal postures, or other regular situations that could affect the nerves in the neck, shoulders, and hands. The patient should report whether the symptoms are more likely to appear at night, or after particular tasks.

Questionnaires. The use of specific questionnaires that score results are quite accurate in assessing the severity of the condition.

Hand Diagram. A diagram of the hand and wrist, usually divided into six regions, is a very useful diagnostic tool. Patients are asked to indicate where their symptoms are, including pain, numbness, or tingling, by locating the affected areas on the diagram. They may also be asked to rate the severity of their symptoms. A diagnosis is probable if at least two of fingers 1, 2, or 3 have these symptoms, and if there is pain in or near the wrist. CTS is possible if at least one of these fingers has symptoms. It is unlikely if there are no symptoms in these fingers, the palm, or the wrist.

Ruling Out Underlying Medical Disorders

One of the most important first steps in diagnosing CTS is to rule out any underlying medical disorders that may be contributing to the condition. Experts emphasize the need to fully examine patients presenting with symptoms of CTS. Relying only on CTS symptoms, and personal or work histories may result in the failure to detect (and thus properly treat) underlying medical conditions that could be serious. If the doctor suspects that an underlying medical condition may be exacerbating the symptoms, laboratory tests will be performed. The doctor may take an x-ray, for example, to check for arthritis or fractured bones.

Raynaud's Phenomenon. A diagram of the hand and wrist, usually divided into six regions, is a very useful diagnostic tool. Patients are asked to indicate the location of their symptoms -- including pain, numbness, or tingling -- by locating the affected areas on the diagram. They may also be asked to rate the severity of their symptoms. A diagnosis is probable if at least two of fingers 1, 2, or 3 have these symptoms, and if there is pain in or near the wrist. CTS is possible if at least one of these fingers has symptoms. It is unlikely if there are no symptoms in these fingers, the palm, or the wrist.

Arthritic Conditions. Arthritic conditions, including rheumatoid arthritis, gout, and osteoarthritis, can all cause pain in the hands and fingers that may mimic carpal tunnel disease. The treatment for these conditions, however, is different.

Muscle and Nerve Diseases. Any disease or abnormality that affects the muscles and nerves, including those in the spine, may produce symptoms in the hand that mimic carpal tunnel syndrome.

Ruling Out Other Cumulative Trauma Disorders

About 25% of patients with suspected work-related cumulative trauma or repetitive stress disorders have evidence of other conditions that resemble, but are not, carpal tunnel syndrome. A definitive diagnosis is often difficult. Most require treatments similar to those used for CTS: rest, immobilization, steroid injections, and even surgery if conservative management is unsuccessful.

Physical Assessment Tests for Carpal Tunnel Syndrome

The following findings are helpful in identifying carpal tunnel syndrome:

• Less sensitivity to pain where the median nerve runs through to the fingers
• Thumb weakness
• Inability to tell the difference between one and two sharp points on the fingertips (this is a late sign of carpal tunnel)

Flick Signal. One important and simple test of carpal tunnel is the "flick" signal:

• The patient is asked, "What do you do when your symptoms are worse?"
• If the patient responds with a motion that resembles shaking a thermometer, then the doctor can strongly suspect carpal tunnel.

Testing for Thumb Weakness. Two questions are useful in determining thumb weakness:

• Can the thumb rise up from the plane of the palm?
• Can the thumb stretch so that its pad rests on the pad of the little finger pad?

Provocation Tests. Certain tests are conducted to produce symptoms:

• Phalen's Test. In Phalen's test, the patient rests the elbows on a table and lets the wrists dangle with fingers pointing down and the backs of the hands pressed together . If symptoms develop within a minute, CTS is indicated. (If the test lasts for more than a minute even patients without CTS may develop symptoms.) This test may be particularly important in determining the severity of CTS and assessing the results of treatment.
• Tinel's Sign. In the Tinel's sign test, the doctor taps over the median nerve to produce a tingling or mild shock-sensation.
• Pressure Provocation Test. The doctor presses over carpal tunnel for 30 seconds to produce tingling or shock in the median nerve.
• Tourniquet Test. This test employs an inflatable cuff that applies pressure over the median nerve to produce tingling or small shocks.
• Hand Elevation Test. The patient raises their hand overhead for 2 minutes to produce symptoms of CTS. The test was recently proven to be accurate and may provide useful information when combined with the Tinel's and Phalen's tests.

Electrodiagnostic Tests

Electrodiagnostic tests analyze the electric waves of nerves and muscles. These tests can help detect median nerve compression in the carpal tunnel.

Electrodiagnostic tests are the best methods for confirming a diagnosis of CTS at this time. Doctors who perform these tests should be certified by the American Board of Electrodiagnostic Medicine, which uses rigorous standards in qualifying doctors. Specific electrodiagnostic tests, called nerve conduction studies and electromyography, are the most common ones performed:

• Nerve Conduction Studies. To perform nerve conduction studies, surface electrodes are first fastened to the hand and wrist. Small electric shocks are then applied to the nerves in the fingers, wrist, and forearm to measure how fast a signal travels through the nerves that control movement and sensation. In suspected cases of CTS, nerve conduction tests can identify over 85% of true carpal tunnel syndrome cases and eliminate 95% of those that are not true CTS. They are less accurate in identifying mild CTS, however. Patients should be sure their practitioners perform tests that compare a number of internal responses -- not just routine testing that records only the responses of muscles located in the palm at the base of the thumb), and those on the second or third fingers.

Nerve conduction tests can also detect causes of symptoms that mimic CTS but should be attributed to other problems, such as pinched nerves in the neck or elbow or thoracic outlet syndrome.

• Electromyography. To perform electromyography, a fine, sterile, wire electrode is inserted briefly into a muscle, and the electrical activity is displayed on a viewing screen. Electromyography can be quite painful and is less accurate than nerve conduction. Some experts question, in fact, whether it adds any valuable diagnostic information. They suggest it be limited to unusual cases or when other tests indicate that the condition is aggressive and may increase the risk for rapid, significant injury.
• Portable electrodiagnostic testing. Portable electronic devices (such as NC-Stat, Neurosentinel, and the Nervepace digital electroneurometer) are being evaluated for measuring nerve conductivity. They are relatively quick and easy to use on a large scale in an industrial facility. However, the Advancing Association of Neuromuscular and Electrodiagnostic Medicine maintains that these devices are experimental and are not effective substitutes for standard electrodiagnostic studies.

Limitations. Electrodiagnostic studies are not well standardized, and certain conditions can skew the results of either test:

• Obesity can slow the speed of electrical conduction.
• Anxiety can slow the speed of electrical conduction.
• Women and the elderly normally have slower conduction times than younger adult men.
• Temperature also affects nerve conduction speed. When undergoing testing, doctors should strictly control room temperature to lessen its impact.

Ruling out other causes is extremely important in order to avoid unnecessary surgery for CTS. Modifications and improvements of these tests are continually being made.

Note: People with abnormal results who have no CTS symptoms are at no higher risk for CTS than those with normal results and no symptoms.

A diagnosis of carpal tunnel syndrome may follow testing the affected hand for numbness, tingling, weakness and/or pain in specific areas. Muscle and nerve conduction tests may also help affirm or rule out carpal tunnel syndrome.

Imaging Techniques

Ultrasound. Ultrasound imaging, a relatively inexpensive technique that uses sound waves, is showing promise. Studies indicate that it can identify up to 85% of CTS cases, and some suggest it is as effective as electrodiagnostic tests. It may be effective for ruling out other causes of hand pain, such as tendon injuries, tenosynovitis (swelling of the tendon lining), cysts, and blood clots in the median artery (a rare complication that can cause the sudden onset of CTS symptoms). However, results are mixed on its accuracy. Newer color Doppler ultrasound and other technological advances are improving the results achieved with this technique. A 2005 study comparing high-resolution ultrasonography with electromyography found that ultrasonography may be helpful for estimating the symptom severity and problems with nerve conduction.

MRI. Magnetic resonance imaging (MRI), an advanced imaging technique, is being adapted to distinguish weak nerve signals from surrounding tissue, so that eventually it may be able to precisely diagnose CTS. However, studies in 2002 note that it requires special expertise, has limited diagnostic accuracy, and is still too expensive at present for routine use. MRI is accurate in diagnosing carpal tunnel syndrome about 80% of the time, compared to about 85% using electrodiagnostic tests, which remains the preferred method of diagnosis. MRI may be most effective for detecting any internal injuries, tumors, arthritis, or joint damage that might be causing the problem. It may also be valuable in selecting surgical candidates when electrodiagnostic tests produce unusual results or indicate more severe disease than expected. Additionally, an MRI may be useful for evaluating patients if surgery fails to bring relief.

Treatment

It is critical to begin treating early phases of carpal tunnel syndrome before the damage progresses. A conservative approach to CTS, which may include corticosteroid injections and splinting, is the first step in treating this disorder.

Nevertheless, relapse is common, and studies suggest that surgery is a better option for severe CTS. In one study, 89% of patients who had conservative treatments suffered a recurrence of symptoms within a year. Conservative treatments work best in men under 40. They do not work as well in young women. The conservative approach is also most successful in patients with mild carpal tunnel syndrome. Even among these patients, however, one study found that 60% of patients can expect a relapse. Some researchers are reporting better results when specific exercises for carpal tunnel syndrome are added to the program of treatments.

Limiting Movement. If possible, the patient should avoid activities at work or home that may aggravate the syndrome. The affected hand and wrist should be rested for 2 to 6 weeks. This allows the swollen, inflamed tissues to shrink and relieves pressure on the median nerve. If the injury is work related, the worker should ask to see if other jobs are available that will not involve the same actions. Few studies have been conducted on ergonomically designed furniture or equipment, or on frequent rest breaks. However, it is reasonable to ask for these if other work is not available.

Conservative Treatment Approach. In a major analysis, the following conservative approaches were shown to provide symptom relief:

• Wrist splints
• Corticosteroids (steroids). Injected or short-term oral corticosteroids may be tried if previous methods fail. People with diabetes may find additional relief by including insulin injections with steroid injections.
• Yoga. In one study, 8 weeks of regular yoga practice reduced pain significantly more than splinting.

A major analysis of other conservative approaches found that patients had no significant relief from nonsteroidal anti-inflammatory drugs (NSAIDs). NSAIDs include common pain relievers such as aspirin and ibuprofen (Advil). The same report also found no benefits from diuretics, magnet therapy, laser acupuncture, vitamin B6, exercise, or chiropractic care. Other approaches being investigated include omega-3 fatty acid supplements and cognitive-behavioral therapy.

Underlying Conditions. It is important to treat any underlying medical condition that might be causing carpal tunnel syndrome. For example, reducing inflammation in rheumatoid arthritis or other forms of inflammatory disorders that directly cause CTS is very helpful.

Hypothyroidism and diabetes are diseases that are associated with an increased risk of CTS. The treatments for such diseases may offer some relief for CTS symptoms. For example, insulin helps nerves heal. A study of patients with CTS and type 2 diabetes found that patients who had an initial steroid injection followed by 7 weekly insulin injections had significantly less pain than those who received sham therapy (placebo). More research is needed on the effects of insulin injections in patients with CTS.

Wrist Splints

Wrist splints are used to keep the wrist from bending. They are not as beneficial as surgery for patients with moderate to severe CTS, but they appear to be helpful in specific patients. In one study, the best success rates were in patients with mild to moderate nighttime symptoms of less than a year's duration. In selected patients, up to 80% reported fewer symptoms, usually within days of wearing the splint.

Although typically the splint is worn at night or during sports, one 2000 study reported that wearing it full time is most beneficial. (In the study, few patients actually complied with the regimen and wore them full time, but any regular use appeared to improve nerve function and symptoms.) The splint is used for several weeks or months, depending on the severity of the problem, and may be combined with hand and finger exercises. A 2005 study reported that a 6-week course of at-night splinting reduced symptom severity in people with CTS and that the benefits were still evident after 1 year.

Corticosteroids

Corticosteroid Injections. Corticosteroids (also called steroids) reduce inflammation. If restriction of activities and the use of painkillers are unsuccessful, the doctor may inject a corticosteroid into the carpal tunnel. Some experts recommend them for patients with CTS whose symptoms are intermittent, and there is no evidence of a permanent injury. In CTS, steroid injections (such as cortisone or prednisolone) shrink the swollen tissues and relieve pressure on the nerve. Evidence strongly suggests that they offer relief in more than 75% of CTS patients. It should be noted that the pain may increase for a day or two after the injection, and skin color may change.

A study comparing the benefits of two steroid injections (8 weeks apart) to a single injection in the treatment of CTS found the patients did not significantly benefit from the second shot. One injection is therefore enough to achieve the maximum benefit of this treatment.

Unfortunately, in most cases, steroid injections provide only temporary relief, although studies comparing steroid injection to surgery have produced conflicting results. In a major analysis, after 1 month, injections were no more effective than placebo (sham) injections.

However, a recent analysis compared the effects of local steroid injection versus surgery in patients with new CTS of at least 3 months' duration. Over the short term, local steroid injection was better than surgery for relieving symptoms of CTS. And after 1 year, local steroid injection was as effective as surgery. Another study compared steroid injection with open-release surgery and found that the surgery resulted in better outcomes, but not improved grip strength, in patients with CTS over a 20-week period.

Most doctors limit steroid injections to about three per year, since they can cause complications, such as rupture of tendons, nerve irritation, or more widespread side effects such as hypertension or elevated blood sugar levels.

Low-Dose Oral Corticosteroids. Oral corticosteroids are medicines taken by mouth. Short-term (1 to 2 weeks), low-dose use of corticosteroids may provide long-term relief. People with diabetes should not take oral corticosteroids.

Yoga and Other Exercise Programs

Yoga. Some evidence suggests that yoga practice may be specifically very helpful for carpal tunnel, since yoga postures are designed to stretch, strengthen, and balance upper body joints. In one study, people who practiced yoga for 8 weeks experienced significantly reduced symptoms compared to wrist splints or no treatment at all. Two other small studies also reported improvement in pain relief. Positive effects may take a few weeks of regular practice of at least two sessions a week.

General Exercise Program. Some experts have reported that people who are physically fit, including athletes, joggers, and swimmers, have a lower risk for cumulative trauma disorders. Although there is no evidence that exercise can directly improve CTS, a regular exercise regimen using a combination of aerobic and resistance training techniques strengthens the muscles in the shoulders, arms, and back, helps reduce weight, and improves overall health and well-being. In one 2001 study, CTS patients experienced symptom relief and signs of improved nerve conduction after 10 months of participation in an aerobic exercise program (such improvements appeared to be due to both weight loss and higher oxygen levels in the blood). One study found that most people with CTS felt improvement after two months of physical therapy that included exercises to improve balance and posture. People with any chronic medical condition or with risk factors for heart disease should check with their doctors about an appropriate exercise regimen.

Physical Therapy and Carpal Bone Mobilization

If symptoms subside, the patient may proceed with a supervised program of joint mobilization and hand and wrist strengthening and stretching, usually offered by physical or occupational therapists. Hand and wrist exercises may be most beneficial for patients with mild to moderate disease who are also treated with splints and other conservative measures.

Ultrasound

Ultrasound employs high-frequency sound waves directed toward the inflamed area. The sound waves are converted into heat in the deep tissues of the hand, which opens the blood vessels and allows oxygen to be delivered to the injured tissue. A major analysis suggested this approach may be effective when used for seven weeks or more.

Nonsteroidal Anti-Inflammatory Drugs (NSAIDs)

Nonsteroidal anti-inflammatory drugs (NSAIDs), which include aspirin and ibuprofen (Advil), are the most common pain relievers used for CTS. They block prostaglandins, the substances that dilate blood vessels and cause inflammation and pain. Unfortunately, as with most other medications used for carpal tunnel syndrome, there are few well-conducted studies to determine their role in CTS. To date, there is no evidence that they offer any significant relief, and regular use can have serious side effects.

NSAIDs Used. Non-steroidal anti-inflammatory drugs (NSAIDs) are commonly used to relieve joint pain and inflammation. There are dozens of NSAIDs. The following are the most common:

• Over-the-counter NSAIDs include aspirin, ibuprofen (Advil, Nuprin, Motrin IB, Rufen), naproxen (Aleve), and ketoprofen (Actron, Orudis KT).
• Prescription NSAIDs include ibuprofen (Motrin), naproxen (Naprosyn, Anaprox), flurbiprofen (Ansaid), diclofenac (Voltaren), tolmetin (Tolectin), ketoprofen (Orudis, Oruvail), dexibuprofen (Seractil), and indomethacin (Indocin).

Regular use of even over-the-counter NSAIDs may be hazardous for anyone. Long-term use can cause stomach problems, such as ulcers and bleeding, and possible heart problems. In April 2005, the Food and Drug Administration (FDA) asked drug manufacturers of NSAIDs to include a warning label on their product that alerts users of an increased risk for cardiovascular events and gastrointestinal bleeding. NSAIDS have been associated with the following side effects:

• Ulcers and gastrointestinal bleeding are the major danger with long-term use of NSAIDs.
• Increased blood pressure -- most NSAIDs appear to pose this risk, with higher risks observed with piroxicam (Feldene), naproxen (Aleve), and indomethacin (Indocin). Sulindac has the smallest effect; aspirin has no risk. People with hypertension, severe vascular disease, kidney, or liver problems, and those taking diuretics, must be closely monitored if they need to take NSAIDs.
• Delay in emptying of the stomach -- this could interfere with the actions of other drugs. The elderly are at special risk.
• Kidney abnormalities -- these have been reported in people taking NSAIDs, which resolve when the drugs are withdrawn. Report any sudden weight gain or swelling to a doctor. Anyone with kidney disease should avoid these drugs.

Other side effects include:

• Dizziness
• Tinnitus (ringing in the ear)
• Headache
• Skin rash
• Depression
• Confusion or bizarre sensation (in some higher-potency NSAIDs, notably indomethacin)
• Possible higher risk for miscarriage (particularly if the NSAID is taken for more than a week or around the time of conception)
• There is a slight risk for liver abnormalities.

COX-2 Inhibitors (Coxibs). COX-2 inhibitors block an inflammation-promoting enzyme called COX-2. This class of drugs was initially believed to work as well as traditional NSAIDs, but with fewer stomach problems. However, numerous reports of heart attacks and stroke have prompted the FDA to re-evaluate the risks and benefits of the COX-2s. Rofecoxib (Vioxx) and valdecoxib (Bextra) have been withdrawn from the U.S. market following reports of heart attacks in patients taking the drugs. At the time of this update, Celecoxib (Celebrex) was still available, but labeled with strong warnings and a recommendation that it be prescribed at the lowest possible dose for the shortest duration possible. Patients should ask their doctor whether the drug is appropriate and safe for them.

Other Conservative Approaches

Ice and Warmth. Ice may provide benefit for acute pain. Some patients have reported that alternating warm and cold soaks have been beneficial. (If hot applications relieve pain, most likely the problem is not caused by CTS but by another condition producing similar symptoms.)

Anesthetic Injections. In some cases, injections of an anesthetic (such as lidocaine) may be helpful. A recent small study compared a painkilling lidocaine patch with a combination lidocaine-steroid injection. The study found the daily use of a 5% lidocaine patch reduced pain as well as the injections. More patients in the patch group reported satisfaction with their treatment. The lidocaine patch is less painful than injections because it is worn on the skin and doesn't require a shot. Doctors noted improvements in 88% of the patients in the patch group, compared with 74% of the patients in the injections group.

Pheresis. The word "pheresis" means to carry. In the case of carpal tunnel, pheresis is a technique being investigated to deliver (to carry) a corticosteroid cream deep within the wrist. One such technique called iontophoresis uses an electrical current, and another called phonophoresis uses ultrasound. One study recently found steroid injections to be superior to iontophoresis and phonophoresis in the treatment of CTS.

Diuretics. Diuretics such as trichlormethiazide reduce fluid in the body. They are sometimes used to treat CTS. However, studies have not reported any significant benefits with these agents.

Low-Level Laser Therapy. Some investigators are working with low-level laser therapy (LLLT), which generates extremely pure light in a single wavelength. The procedure is painless, but studies are mixed on whether it is any more effective than sham treatment. One major analysis reported that laser therapy was more effective over time than steroid injections (although it does not appear to provide much immediate relief.) A 2004 study comparing LLLT with a sham (inactive) therapy reported no significant differences in outcomes between the two groups.

Muscle Stimulation. Two investigative procedures called automated or electrical twitch obtaining intramuscular stimulation (ATOIMS or ETOIMS) are showing promise. ATOIMS uses an automated mechanical device that vibrates the muscle using a tiny pin. (The sensation is described as similar to a mosquito bite.) ETOIMS uses an extremely mild electrical current. They can also be used together. Both approaches cause the muscles to twitch and then relax until the process is completed. Discomfort is minimal. Small studies are reporting some help in relieving a number of conditions that cause chronic pain, including carpal tunnel syndrome.

Alternative Therapies

Many alternative therapies are offered to sufferers of carpal tunnel syndrome and other repetitive stress disorders. Few, however, have any proven benefit. People should carefully educate themselves about how alternative therapies may interact with other medications or impact other medical conditions, and should check with their doctor before trying any of them.

Vitamin B6 (Pyridoxine). Vitamin B6 (pyridoxine) is often used for carpal tunnel syndrome. Studies have not supported its benefits, however, either in oral or cream form. It should also be noted that excessively high doses of vitamin B6 can be toxic and cause nerve damage.

Acupuncture. Acupuncture may be beneficial. New techniques employing painless laser acupuncture may prove to be particularly effective. The National Institutes of Health issued a Consensus Statement on Acupuncture in 1997, which declared this ancient form of treatment useful as a supplement to standard treatment or even as part of a comprehensive management program for CTS.

Chiropractic Therapies. Chiropractics has been useful for some people whose condition is produced by pinched nerves. In one small study, the technique was as effective as medications or wrist splints for relief of pain, though further research is needed.

Magnets. Magnets are a popular but unproven therapy for pain relief. One small study of patients who wore magnets attached to their wrists showed no benefits over those who wore a nonmagnetic placebo (sham) device, although both groups did experience pain relief, perhaps due to a placebo response.

Cognitive Behavioral Therapy and Stress Management

Research indicates that anxiety, depression, and even pain related to CTS can be relieved to some extent with cognitive behavioral therapy. The focus of this therapeutic approach is to change negative thinking about one's ability to manage pain. Cognitive behavioral therapy is particularly helpful in defining and setting limits. It may be expensive and not covered by insurance, although the therapy is usually of short duration, typically six to 20 one-hour sessions, plus homework, which usually includes attempting a task that the patient has avoided because of negative thinking. Even if people cannot afford this type of therapy, support groups for carpal tunnel syndrome and other sufferers of repetitive stress injuries can be very helpful for exchanging information, specific advice, and solace. Stress management techniques can also be useful in dealing with the psychological and emotional issues accompanying these injuries.

Surgery

Every year more than 200,000 people in the US undergo surgeries for carpal tunnel syndrome. Surgery for CTS is among the most common hand surgeries. In various trials, 70 - 90% of patients who underwent surgery were free of nighttime pain afterward.

Candidates for Surgery

Although evidence strongly suggests that surgery is more effective than conservative approaches (at least in patients with moderate to severe CTS), the decision about whether to have surgery to correct CTS, and when to have it, is a troubling one for patients. Electrodiagnostic and other tests used to confirm the presence of CTS are not very useful in determining the best candidates for surgery. For example, results suggesting severe CTS may not relate at all to surgical success or the lack of it.

In general, patients with the following characteristics are less likely to respond to conservative treatment and, therefore, might benefit from surgery:

• Older than 50 years of age
• Symptoms lasting 10 months or longer
• Continual numbness
• Muscles in the base of the palm have begun to shrink
• Symptoms occur within 30 seconds during a Phalen's test

According to a 2002 study, if none of these factors are present, conservative therapies (splinting and anti-inflammatory agents) are effective in two thirds of patients. However, the conservative approach was ineffective in 60% of patients if only one of these factors were present, in 83% with only two of them, and in virtually all patients who had three or more.

Surgery does not cure all patients, and because it permanently cuts the carpal ligament, some wrist strength is often lost. A number of experts believe that release surgery is performed too often. They recommend aggressive conservative treatment (such as splints, anti-inflammatory agents, and physical therapy) before choosing the more invasive option (surgery). Nevertheless, other experts argue that CTS is often progressive and will worsen over time without surgery. Furthermore, evidence now shows that surgery is better than splints and conservative measures for the relief of pain. Factors that may increase the chances for successful surgery:

• Having surgery performed within 3 years of the diagnosis of the disorder
• Being in good general health
• Having very slow nerve conduction results, but also having some muscle strength before surgery
• Symptoms are worse at night than during the day

Factors that may reduce the chances for success:

• Being elderly may affect the chances of successful surgery. However, a study found that the majority of patients over age 65 who had surgery were either completely or very satisfied.
• Having very severe symptoms before surgery may reduce the chance for successful surgery.
• Performing heavy manual labor, particularly working with vibrating tools, may lead to a less successful surgery. Medical evidence has found that only slightly more than half the people who used vibrating hand-held tools were symptom-free 3 years after a CTS operation.
• Having very poor nerve conduction results before surgery may reduce the chance for successful surgery. However, some patients with severe symptoms who have normal neurological and physical test results, could still experience significant relief from CTS surgeries.
• Patients who are on hemodialysis have good initial success, but approximately half deteriorate in about a year and a half.
• Alcohol abuse can negatively affect the results of CTS surgery.
• Poor mental health can lead to less successful surgery.
• Patients with diabetes and high blood pressure may be more likely to require a second operation.

Factors that make no difference in results:

• Patients whose CTS is due to nerve damage from medical conditions, such as diabetes, rheumatoid arthritis, or hypothyroidism. Such patients appear to have the same outcome as those without such conditions, and such disorders should not preclude them from surgery.

Standard Release Surgical Procedures

Open Release Surgery. Traditionally, surgery for CTS entails an open surgical procedure performed in an outpatient facility. In this procedure, the carpal ligament is cut free (released) from the median nerve. The pressure on the median nerve is therefore relieved. The surgery is straightforward.

In treating carpal tunnel syndrome, surgery may be required to release the compressed median nerve. The open release procedure involves simply cutting the transverse carpal ligament.

The Mini-Open Approach. In recent years, more surgeons have adopted a "mini" open -- also called short-incision -- procedure. This surgery requires only a one-inch incision, but it still allows a direct view of the area (unlike endoscopy, which is viewed on a monitor). The mini-open approach may allow for quicker recovery while avoiding some of the complications of endoscopy, although few studies have investigated its benefits and risks. In a 2005 report, the mini-open approach was directly compared with open release surgery. The recovery time in patients receiving the mini-open approach was shorter than with the open approach,  and results were about the same 30 months after the surgery.

Endoscopy. Endoscopy for carpal tunnel syndrome is a less invasive procedure than standard open release. 

• A surgeon makes one or two 1/2-inch incisions in the wrist and palm, and inserts one or two endoscopes (pencil-thin tubes).
• The surgeon then inserts a tiny camera and a knife through the lighted tubes.
• While observing the underside of the carpal ligament on a screen, the surgeon cuts the ligament to free the compressed median nerve.

Patients report less pain than those who had the open release procedure, and return to normal activities in about half the time. Nevertheless, at this time the best evidence available does not show any significant long-term advantages of endoscopy over open release in terms of muscle or grip strength or dexterity. The endoscopic approach may even carry a slightly higher risk of pain afterward. This may be due to a more limited view of the hand with endoscopy. (In the open release procedure, the surgeon has a full view of the structures in the hand.) One report indicated a nearly 3-fold increased risk of reversible nerve injury with endoscopic carpal tunnel release, compared with open carpal tunnel release. On the other hand, a recently published review of 486 patients, who had a total of 753 endoscopic release procedures, showed an extremely low number of complications following the procedure. This study calls into the question the widely held belief that endoscopy carries a higher risk of complications. The study also noted that 90% of the patients returned to their original line of work.

Recovery After Surgery

Timing for Recovery. Patients should expect the following course:

For some patients, release surgery relieves CTS symptoms of numbness and tingling immediately.

• People who have the operation on both hands are completely incapacitated for about two weeks and must have someone to help them at home.
• Returning to strenuous work right after surgery may cause the symptoms to return. Patients generally stay out of work for at least a month and often much longer, depending upon the type of surgery and severity of the condition. Recovery time appears to be faster with endoscopy than with open release.
• Immediately after surgery patients usually experience a decline in grip strength and dexterity. Studies have reported a wide range of recovery in this area. In one study, grip and pinch strengths reached better levels than before surgery within 6 weeks. In another study, however, grip strength and dexterity did not return to before-surgery levels until 25 weeks after open surgery. The scar may remain tender for up to a year.
• Peak improvement (the best level of improvement a patient can reach) may take a long time; in one study, it took an average of almost 10 months.

Physical Therapy. Physical therapy is very important to help rebuild wrist strength. While physical therapy does not reduce the recurrence (return) of symptoms or improve the long-term benefits of surgery, it does accelerate recovery after surgery. Hand exercises can help restore circulation, muscle strength, and joint flexibility in the hand and wrist. Wearing a splint to immobilize the wrist after surgery has no benefits.

Complications and Long-Term Outcome

Treatment failure and complication rates of CTS surgery vary.

Complications after surgery may include the following:

• Nerve damage with tingling and numbness (usually temporary).
• Infection.
• Scarring.
• Pain.
• Stiffness. Loss of some wrist strength is a complication that affects between 10% and a third of patients. Endoscopy may have better results than open release. Some patients who have jobs requiring significant strength of the hand and wrist may not be able to perform them after surgery. Such workers may also have problems in other parts of the upper body, including elbows and shoulders. These problems do not go away with surgery and can persist. Studies indicate that between 10 - 15% of patients change jobs after a CTS operation.

If pain and symptoms return, the release procedure may be repeated.

Reasons for procedure failure include:

• Incomplete release of the ligament
• Extensive scarring
• Recurrence of the disorder due to underlying medical conditions

Patients who had open release surgery appear more likely to require repeat operations compared with those who have had endoscopic surgery.

Procedures for Treating Surgical Failure or Recurring Symptoms

Neurolysis. In severe cases or when scarring is extensive after surgery, surgeons may choose to sever the nerves that are responsible for the pain, using a procedure called external or internal neurolysis. The procedure may extend recovery time substantially, and the need for repeat surgeries may be higher in those who undergo the procedure. One report indicated that neurolysis should be considered if there has not been any recovery within 3 months after surgery, after which improvement is unlikely. It is unclear if this approach offers any benefits over conservative measures to free the nerve from surrounding scar tissue.

Implants. In another procedure for recurrent carpal tunnel syndrome, doctors may take muscle flaps or even fatty tissue from other parts of the body and implant them at the site of the nerve injury. Such flaps enhance the development of new blood vessels, provide padding, and possibly serve as a bed for nerve regrowth. These implants may be used with or without cutting the nerve. Another procedure called vein wrapping uses grafts taken from veins to help protect the scarred nerves.

Resources

• www.aanem.org -- Advancing Association of Neuromuscular and Electrodiagnostic Medicine
• www.apta.org -- American Physical Therapy Association
• www.aoec.org -- The Association of Occupational and Environmental Clinics
• www.aaos.org -- American Academy of Orthopaedic Surgeons
• www.assh.org -- American Society for Surgery of the Hand
• www.ampainsoc.org -- American Pain Society
• www.iasp-pain.org -- Association for the Study of Pain
• www.aan.com -- American Academy of Neurology
• www.nih.gov/niams -- National Institute of Arthritis and Musculoskeletal and Skin Diseases
• www.ninds.nih.gov -- National Institute of Neurological Disorders and Stroke
• www.nlm.nih.gov/medlineplus/carpaltunnelsyndrome.html -- Information on CTS
• www.cdc.gov/niosh/homepage.html -- National Institute for Occupational Safety and Health
• www.ctdrn.org -- Cumulative Trauma Disorders Resource Network
• www.workerscompensationinsurance.com -- Resources for injured workers
• www.keybowl.com -- orbiTouch keyboard
• www.ergodevices.com -- Hand and wrist support keyboard

References

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