Carpal tunnel syndrome is a condition in which there is extreme pressure on the median nerve. The median nerve is the nerve in your wrist that allows for movement and feeling. When there is pressure on this nerve it causes carpal tunnel syndrome.
According to the National Institutes of Health, annual spending for medical care for carpal tunnel syndrome (CTS) is in excess of $2 billion. CTS is one of the most common upper extremity defects, afflicting between 1 and 5% of the American population.
Much about CTS is not clearly understood even though it seems to affect many individuals.
What is carpal tunnel syndrome (CTS)?
CTS is caused when pressure is applied to the median nerve by surrounding structures for a prolonged period of time.
The median nerve runs through the palmar area of the forearm through the wrist and into the hand. According to the Mayo Clinic, the median nerve passes through a space in the wrist called the carpal tunnel. It is in this tunnel that the pressure on the median nerve occurs which leads to CTS.
While CTS is currently classified as a form of neuropathy (nerve dysfunction or damage), the median nerve isn’t defective or problematic. The problem resides with the structures and tissues that are in or near the carpal tunnel and surround the median nerve.
Below is a video the briefly details the anatomy of the carpal tunnel area as well carpal tunnel syndrome.
What are the potential causes of CTS?
The National Institute of Neurological Disorders and Stroke (NINDS) reports that CTS may be caused by wrist injuries, overactive pituitary gland, hypothyroidism, and arthritis. They also claim that repeated flexing or bending of the wrist, pregnancy, and menopause could contribute to CTS.
The report of repeated flexing and bending of the wrist being a contributing factor in CTS has led many to speculate about a positive association between CTS and certain occupations.
The Arthritis Research UK (ARUK) has claimed that occupations involving typing, repetitive wrist movements and usage of vibrating tools may lead to an onset of CTS.
The Mayo Clinic has also claimed that the usage of vibrating tools or other occupations that require “prolonged and repetitive flexing of the wrist” may contribute to the development of CTS.
These claims concerning occupation and CTS make sense. There are many occupations that do require the same wrist and finger motion on a day-to-day basis. A number of the same people who occupy these positions have been known to experience CTS.
However, a positive association between CTS and specific occupations is anything but certain.
In reading a number of pamphlets and studies concerning CTS there seems to be an assumed belief about occupations that involve repetitive wrist and finger movements must contribute in some way to the development of CTS. Yet, data supporting this notion has proven to be elusive.
A study conducted in Sweden that was designed to examine the prevalence of CTS in a population pointed to this fact.
Atroshi reported the difficulty of attributing CTS to specific occupations due to the “absence of accurate” data estimating the prevalence of CTS.
Even though the Mayo Clinic affirms a probable link between workplace factors and CTS they go on to admit that it is not conclusive.
In the previously referenced document from Mayo, they state, “the scientific evidence is conflicting [and] factors haven’t been established as direct causes of [CTS].”
Ring also confirms this position. He was part of a group that examined a large number of medical studies concerning CTS in an attempt to determine potential causal factors. They concluded that “evidence supporting occupational risk factors was felt to be poor.”
The scientific and medical communities have thus far been frustrated in their attempts to determine what actions serve as the causation of CTS.
This fact has left researchers wondering if there might be a genetic pattern related to CTS.
There are many symptoms of carpal tunnel that patients may experience. If you think you have carpal tunnel syndrome and experience any of these you should seek a medical opinion to determine further actions.
Numbness, Pain, Tingling
Three of the first ten common symptoms of carpal tunnel syndrome are numbness, pain, and tingling in the hands, wrist, or forearm.
Numbness and pain in these regions are usually intense. The pain is uncomfortable and causes a disruption in everyday activities. The pain often keeps one awake at night, and can even awake one from a deep sleep.
There can often be stiffness in your hand in the morning. This can sometimes make simple activities such as gripping a toothbrush more difficult.
The numbness and pain can get progressively worse over time. For example, your thumb muscles will get weaker. It will become difficult to open a can of hold a screwdriver.
Tingling is also often felt with carpal tunnel syndrome. The tingling is often described as a “pins and needles” feeling throughout the hands, wrists, and forearm.
Loss of Muscle Strength
A common symptom of carpal tunnel syndrome is the loss of muscle strength in your wrist, hand, and fingers. As the pain progresses so does the muscle pain.
Your fingers, primarily your thumb loses muscle strength. Activities that involve your thumb become harder to accomplish.
Because your thumb one of the more important fingers for accomplishing tasks this becomes a more difficult adjustment.
With the pain and muscles loss in your thumb opening cans and gripping objects become more difficult, even sometimes impossible.
Another common symptom of carpal tunnel syndrome is random dropping of objects for no apparent reason.
Due to the muscles weakening and compression of the nerve you may find combing your hair or holding a fork becomes difficult and results in accidentally dropping objects.
While your fingers do not look swollen with carpal tunnel syndrome a symptom of the syndrome is that they may feel that way.
Often patients report that their fingers feel as if they are swollen and useless. Your fingers will not appear to be swollen but rather just feel as if they are.
Hot or Cold?
Another symptom of carpal tunnel syndrome is the inability to differentiate between hot and cold objects. As the carpal tunnel progresses patients sometimes have trouble feeling the temperature of certain objects.
If you are experiencing this symptom be careful to touch objects that can burn your skin without your knowledge. Be sure to seek medical attention right away.
Patients with carpal tunnel syndrome often report about a burning feeling in their hands. The burning feeling is a result of the carpal tunnel and comes at times when one is usually sleeping or the hand is resting.
The burning feeling is often felt around the thumb and two fingers directly next to it. When one feels a burning sensation they also feel the “pins and needles” sensation as well.
Another common symptom of carpal tunnel syndrome is an itching feeling in the hand. The itching feeling can also be felt in the thumb and surrounding two fingers.
The itching sensation often comes with the numbness sensation that other patients report feeling as a result of the compression of the median nerve. The itching feeling is often subtle, but noticeable.
Lastly, the tenth common symptom of carpal tunnel syndrome is a feeling that the hand has “fallen asleep.” Patients often report a need to shake their hand to “awaken” it. This feeling often occurs in the morning time.
After a night of rest, one feels their hand needs to be awake. The hand itself is not asleep, but the compression of the nerve causes one to feel as if the hand is asleep. Shaking of the hand will not help awaken it, but rather do nothing.
These symptoms often occur in patients who have carpal tunnel syndrome. Just because you are not experiencing all ten of these symptoms does not mean you may not have carpal tunnel syndrome.
If you are experiencing these symptoms seek medical help to determine a proper diagnosis to be sure.
Is there a relationship between genetics and CTS?
In 2002, Hakim performed a twin study in a group of women between 20 and 80 years of age. This was the first study performed to determine if there is a genetic contribution for CTS. The results were groundbreaking. It was concluded that genetics was the biggest risk factor for CTS.
Hakim and his colleagues determined that for women up to half of the cases of CTS could be directly-related to genetics.
Researchers have pondered this question long before Hakim’s study. Danta (in 1975) displayed a potential inheritance of CTS via male-to-male inheritance through evaluating 3 generations of one family.
To date, researchers have been able to identify at least four genes that are attributed to CTS. According to the National Library of Medicine’s Online Mendelian Inheritance in Man database, all four genes are located on the 18th chromosome.
The inheritance pattern has been shown to be autosomal dominant. As complicated as this sounds it means two things. First, the chromosome that the genes are located on is one of the 22 autosomes in human cells. Autosomes are chromosomes other than the X and Y chromosomes that are associated with gender.
Second, that the pattern of inheritance is dominant means that it is easy to inherit a gene that may lead to developing CTS. A basic understanding of genetic inheritance makes it much easier to understand how this is so.
Humans normally have 46 total chromosomes. We inherit 23 of them from our mother and 23 from our father at conception. All of those chromosomes have genes relating to all of the physical characteristics of humans.
If the pattern of inheritance for CTS was recessive then we would have to inherit two chromosomes (one from our mother and one from our father) that carried the genes linked to CTS. Being that the inheritance is dominant, we need only inherit one chromosome with the CTS genes.
What this means is that if one parent had CTS then the probability that their child would inherit the genes linked to CTS would be 0.25 to 0.5. If both parents had CTS then the probability could be as high as 1.0 (absolutely certain).
A link between genetics and CTS has been established. However one must also understand that specific environmental exposures and lifestyle choices often play a role in determining if those genes will operate in the individual. They can effectively “turn on” and “turn off” a gene.
What these specific environmental exposures and lifestyle choices are and how they interact with CTS genes are still not known.
What are some of the symptoms of CTS and what activities make them worse?
While symptoms of CTS vary from person-to-person, physicians have determined a set of symptoms that are generally typical for most patients with CTS. LeBlanc recommends looking for pain, numbness, and/or tingling sensations in the thumb, index and middle fingers.
Other symptoms include a weakening of the muscle in control of the thumb and an absence of pain in the back of the hand and the palm of the hand.
The American Academy of Orthopaedic Surgeons (AAOS) has determined that there are 2 actions that tend to make these symptoms worse. They are driving and holding a telephone up to their ear. When these occur together then they should heighten one’s suspicion of CTS being present.
How physicians test for CTS
Two diagnostic tests that have been used to help physicians confirm the presence of CTS in their patients are the Phalen’s maneuver and Tinel’s sign. Urbano provides instruction for both of these tests.
The Phalen’s maneuver which places both wrists at 90 degrees of flexion for approximately 60 seconds. If the patient experiences tingling or numbness in their thumb, index, middle, or part of their ring fingers presents a positive sign (see the video, below).
The Tinel’s sign is performed by compressing or percussing with a rubber mallet the area just over the carpal tunnel, which is where the median nerve passes. A positive sign is if the patient experiences tingling and numbness in the same area as the Phalen’s maneuver (see the video, below).
While these tests, especially Phalen’s, have developed a reputation for conclusively diagnosing the presence or absence of CTS, AAOS reminds us that there is no one examination or test that positively identifies CTS.
The best diagnosis is based upon a body of data that consistently point toward CTS. Some of the most significant data is not gathered from an exam but from the physician’s interview with the patient regarding the history of their symptoms (length, severity, and location).
Many physicians will also evaluate the strength of the thenar and abductor pollicis brevis muscles. Both of these muscles help to control the movement of the thumb.
AAOS also recommends employing nerve conduction test in order to prevent other nerve issues from confusing the physician into misdiagnosing for CTS. Many of the symptoms of CTS are also classic of other neuropathies and endocrine gland issues.
Contrary to popular belief, AAOS rules that MRI and CT scan to be of little use in positively diagnosing the CTS. It was their opinion that these imaging techniques are best used to eliminate other defects, such as fractures.
The stages of CTS (severity)
LeBlanc provides a description of the 3 stages of CTS. They are mild, moderate and severe. The difference between each of these stages is likely to be related to the condition of the median nerve and the pressure being placed upon it.
These 3 stages are defined based upon these criteria: duration of symptoms, 2-point discrimination test, the condition of the muscles controlling the thumb (weakness and atrophy), electromyogram (measures how the thumb muscles respond to signals from the brain) and nerve conduction tests.
Mild and moderate CTS will both result in symptoms that have lasted longer than 1 year. Severe CTS will have been much more prolonged, as it will present symptoms lasting longer than 1 year.
Those with mild CTS will have a normal 2-point discrimination. The moderate and severe forms both present with abnormal 2-point discrimination tests. The severe form will be much worse compared to the moderate.
Mild CTS will most likely present with acceptable thumb muscle conditioning, electromyography, and nerve conduction results. Not so with moderate and severe CTS.
Moderate CTS will present with minimally weakened and atrophied thumb muscles. It will also display a mild denervation per electromyography. Nerve conduction tests may reveal mild velocity decrease (the signal sent via the median nerve may be somewhat slower than normal).
Severe CTS presents with high degrees of thumb muscle weakness and atrophy. The median nerve also presents a marked inability to carry the message from the brain to the fingers in any efficient means. This is displayed by denervation via electromyography and severe velocity decrease via nerve conduction test.
Treatment of Mild and Moderate CTS
The treatment of CTS is based upon the severity of CTS that each patient possesses. Most patients will most likely have a mild or moderate form. Both of which tolerate conservative forms of treatment.
Recommended management of mild and moderate CTS, per the NINDS, is 24-hour splinting, lifestyle and activity accommodations, medication (NSAIDs and corticosteroids) and stretching.
They also report that some have experienced relief of symptoms via acupuncture and chiropractic adjustments.
An example of a chiropractic self-release exercise can be viewed below.
According to Elliott, massage therapy coupled with trigger-point release has revealed itself to be a legitimate alternative therapy for CTS. Patients who attempted this experienced a notable improvement in their symptoms after 2 weeks of treatment.
Physical therapy is also recommended. Three recommended exercises are detailed in the following video. These three exercises are nerve gliding, chest stretch, and rib mobilization.
Treatment of Severe CTS when conservative treatment fails
According to the NINDS, CTS surgery has become one the most common procedures performed in the US, today. Two forms are in use (open and endoscopic) and both produce the same result with little difference, except for scarring on the skin.
The purpose of the CTS surgery is to reduce the pressure on the median nerve by cutting the ligament over the carpal tunnel. The following video provides an animation that details the procedure.
Long-term prognosis for patients with CTS
A very small percentage of CTS patients endure permanent issues, due to CTS. According to the NINDS, only 1% of those with CTS will have to endure this.
Is CTS considered a disability?
This largely depends on more factors than whether or not one has CTS.
General social security administration guidelines involve education level, prior work experience, age and a person’s overall physical condition.
How to prevent CTS?
The Mayo Clinic has provided a list of steps to prevent CTS. Some of them include relaxing your grip, take breaks, improving posture and keeping hands warm.