Carpal Tunnel Syndrome: Causes, Symptoms, and Treatment

Carpal tunnel syndrome describes a nerve constriction of the median nerve in the area of the flexor-side wrist. The cause is often unknown, but injuries, inflammation, or degenerative changes cause an increase in pressure in the carpal tunnel with pressure damage to the median nerve.

The damage to the nerve subsequently leads to a degeneration of the thumb ball muscles. The damage also leads to sensory disturbances in the area of the first three fingers, i.e., thumb, index, and middle finger.

Anatomy

The carpal tunnel is a tunnel-like tube. It is located in depth between the thumb ball muscles and the small finger ball muscles. The median nerve runs through it. It is one of the three primary nerves of the arm, which are responsible for the function of the muscles and the sensation of feeling.

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Causes of carpal tunnel syndrome

The pressure on the nerves, for example, as an accompanying symptom in Thoracic outlet syndrome, causes pain. The pain is particularly severe at night. The clinical picture can progress further and trigger a persistent numbness, which extends particularly to the thumb, index, and middle finger. If the disease remains untreated for many years, the thumb ball muscles can also atrophy. In this case, the thumb can no longer be placed powerfully opposite the fingers.

One can differentiate here between 2 basic reasons:

  • Narrowing of the carpal canal (e.g., due to fractures, acromegaly, etc.)
  • Pathologically increased volume in the carpal canal, e.g., due to a tumor.

A definitive cause of carpal tunnel syndrome is usually not identifiable. Those mentioned above and thus known causes of carpal tunnel syndrome account for only a small proportion of all cases that occur.

Very often, women in the “menopausal” area are affected by this disease.

Approximately 1% of all women between 40 and 60 years of age complain at least temporarily about symptoms that indicate carpal tunnel syndrome.

Especially the increased use of computers, caused by using the keyboard and the “mouse,” causes a significant increase in the area of diagnosed carpal tunnel syndrome.

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Symptoms of carpal tunnel syndrome

Carpal tunnel syndrome is a compression syndrome of the median nerve in the area of the carpus. This area is called the carpal tunnel. It is bordered by various bony and muscular structures and a ligament.

The nerve in question runs through it, which supplies parts of the hand with motor and sensory functions. An incarceration here leads to loss and restriction of motor and sensory functions of the hand. To better understand the symptoms, it is advisable to learn more about the roles and tasks of the median nerve.

This nerve supplies the first three fingers, i.e., the thumb, middle, and index finger in parts motor and the skin in this area sensitive. In the case of delicate care, the symptoms show a very characteristic pattern of failure. The nerve supplies the skin of the palm on the thumb side, the skin of the first three fingers, and the skin of the ring finger on the thumb side. On the back of the hand, it supplies the end phalanges of the first three fingers and, to a small extent, the ring finger.

In carpal tunnel syndrome, the area mentioned above of care is subject to sensitive sensory disturbances and even numbness of the skin. The degree of severity depends on the degree of compression.

Also, the closure of the fist is more difficult in carpal tunnel syndrome because the muscles are no longer adequately innervated. In the case of a very pronounced symptomatology and a very advanced compression syndrome, the so-called “oath hand” is produced when the patient is asked to clench his fist. The thumb, index, and middle finger can no longer be wholly bent and are always in an extended position. Although this clinical picture is very concise, it does not always correspond to reality.

In most cases, only the patient’s motor skills and strength are restricted to such an extent that he or she is no longer able to close the fist as forcefully. It is becoming increasingly difficult for the patient to carry objects or perform physical activities that mainly use the thumbs.

The failures just described show the full clinical picture of a median compression syndrome. At the beginning of the incarceration, complaints such as diffuse pain and sensations of discomfort (falling asleep, formication) occur mainly during and after the strain on the wrists. The pain primarily affects the hand but also radiates into the arm.

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Pain

The pain primarily affects the hand but also radiates into the arm.

With increasing compression, the pain occurs at night and, finally, also during the day at rest. The reduced supply to the muscles leads to a so-called atrophy, muscle atrophy. The ball of the thumb flattens out or becomes dented. This can be seen and felt from the outside.

In the further course of the nerve damage, a weakness in gripping occurs, which initially manifests itself mainly in the morning, but then also during the day. Finally, the fine motor skills also suffer from the damage to the median nerve.

In this stage of compression, the pain decreases again, as pain fibers are also destroyed.

Diagnosis of carpal tunnel syndrome

Using ultrasound, the muscle and nerve logs on the wrist can be examined.

The diagnosis of carpal tunnel syndrome is first made using various tests, such as the Phalen test, the carpal compression test, or the Hoffmann-Tinel sign.

To understand the diagnostics used when carpal tunnel syndrome is suspected, it is first necessary to understand the cause:

Excessive compression of the median nerve in the wrist causes it to swell, and it can no longer adequately transmit nerve impulses from the brain.

The median nerve is responsible for the sensitive and motor supply of large parts of the hand.

To find out whether carpal tunnel syndrome is present, it is relatively easy to measure the nerve conduction speed of the median nerve in a side-by-side comparison. To do this, small electrodes are attached to the forearm, and an electrical impulse is applied at the level of the elbow.

The measurement and the side comparison, with the other hand, provide information about the presence of a functional disorder. If – as is usual in many cases – no side comparison is possible because carpal tunnel syndrome is present on both sides, the muscle and nerve logs on the wrist can still be examined using ultrasound.

For this purpose, the head of the ultrasound device is placed on the wrist, and the cross-section of the arm is shown. The picture shows the individual muscles, vessels, and nerves that run along the examined area.

A comparison of the median nerve with the structures running nearby allows conclusions to be drawn about any swelling of the nerve. Finally, the diagnosis of carpal tunnel syndrome can, of course, also be made by clinical examination, in which the various symptoms are examined, and intensive research into the causes is carried out.

There are, for example, various factors that favor carpal tunnel syndrome. After pregnancies, it is relatively typical to suffer from carpal tunnel syndrome due to a change in the hormonal balance.

However, obesity, trauma, or edema in the wrist area can also indicate carpal tunnel syndrome – with the additional presence of restricted mobility and numbness in hand. However, the diagnosis is not difficult to make. Since no special equipment is required for the examination, the examination can usually be performed without prior appointment. The study is generally completed within half an hour.

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Tests for the investigation of carpal tunnel syndrome

There are various clinical tests for the investigation of carpal tunnel syndrome:

The “Phalen test,” named after its inventor George Phalen, is very easy to perform:

Here the patient bends the hand for one minute at most to check whether there is any loss of sensation in the finger area.

If the Phalen test is positive, this is a sign of carpal tunnel syndrome.

Another test is the carpal compression test, in which the examiner applies pressure to the middle of the wrist with both thumbs. After a short time, the examiner stops using pressure and – as with the Phalen test – any loss of sensation in hand is determined. This loss of sensation is also known as paresthesia, and in everyday medical practice is known as the “Hoffmann-Tinel sign.” The Hoffmann-Tinel sign is, therefore, also considered an indication of carpal tunnel syndrome.

The tests mentioned above are very simple and can also be carried out without medical help, for example, together with your spouse. However, if carpal tunnel syndrome is suspected, a doctor should be consulted for final diagnosis and treatment.

X-ray and MRT

Although carpal tunnel syndrome cannot be diagnosed using an X-ray examination, this examination is nevertheless useful. Often other diseases associated with carpal tunnel syndrome are found (e.g., arthrosis of the thumb saddle joint).

A magnetic resonance tomography (MRT) is not useful in most cases.

Only in the case of a concrete suspicion of a tumor is such a complex examination useful.

Therapy of carpal tunnel syndrome

Conservatively, carpal tunnel syndrome can be treated, for example, with the help of a bandage.

Carpal tunnel syndrome does not always require surgery. In the so-called early stages, the administration of vitamin B6 is often sufficient. Under certain circumstances, the therapy can be additionally intensified by a specially adapted nocturnal positioning splint.

If there is no improvement in pain in the medium term and to prevent irreversible damage to the nerves, surgery should be considered.

The decision as to whether or not surgery is appropriate should be weighed up carefully. An experienced nerve specialist (neurologist = specialist for neurology) or hand surgeon can help you with this.

Splint and bandage for the treatment of carpal tunnel syndrome

Carpal tunnel syndrome involves compression of the nerves and blood vessels in the wrist area.

This compression is promoted by bending the hands, for example, when gripping or lifting. In the beginning, one can “shake out” the hands to get rid of the annoying tingling sensation, but in advanced stages, this hardly provides any relief.

If carpal tunnel syndrome is not yet too far advanced, conservative therapy using immobilization can be used in addition to surgery. The aim is to reduce the pressure on the nerves and blood vessels in the wrist. For this purpose, several different splint systems splint and fix the hand. In principle, splints and bandages do not differ in their function, but their material and wearing comfort.

Each manufacturer naturally advertises its product with different advantages, but in the end, it is, of course, the patient’s own decision whether to choose a bandage or a splint.

Different models can be tried on in specialist shops. It is also possible to adapt them individually. However, it is important to make sure that – regardless of which type of immobilization is ultimately chosen – the original purpose of the splint is not forgotten. Fixation of the wrist is inevitably uncomfortable, as it restricts the patient’s physiological freedom of movement. Braces have the advantage that they can be easily removed with a Velcro fastener, and the area underneath can be washed.

Also, the firm plastic plates in the splint protect the wrist from external influences. However, there is a risk that the brace is not worn consistently enough and that the possibility of easy removal may cause a worsening of carpal tunnel syndrome.

Bandages, on the other hand, enclose the wrist tightly and also protect it against injuries from external influences using integrated fabric pads. If a rigid plastic plate is too uncomfortable for splinting, a bandage is certainly a good idea. However, it should be borne in mind when choosing a bandage that it is not an “accessory,” but a medical product that must also fulfill a particular purpose.

Neither the bandage nor the splint should fit so tightly that it causes pain or further numbness. However, immobilization of the wrist must have top priority, as further deterioration of carpal tunnel syndrome can usually only be treated with surgery.

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Operation

For the operation of carpal tunnel syndrome, local anesthesia is sufficient. Cutting the ligament on the hand relieves the pressure on the nerve. Carpal tunnel syndrome requires therapy because the nerve damage can progress, especially if the course is severe and the compression persists for a long time.

In general, conservative therapy may be sufficient for mild compression and mild symptoms. This includes gentle measures and immobilization of the hand, which can be achieved, for example, by a splint and painkilling and anti-inflammatory medication. If the symptoms persist or the compression of the nerve is already well advanced, surgical treatment is necessary. There are two standard surgical techniques used in carpal tunnel syndrome.

The procedures, complications, and follow-up treatment of surgical therapy are explained in more detail below.

Carpal tunnel syndrome surgery is a relatively unproblematic, quick procedure and is rarely associated with complications. For this reason, the surgery is usually performed under regional anesthesia so that the patient is conscious throughout the entire process, while pain elimination only occurs in the arm.

An alternative is a local anesthetic procedure directly on the nerve plexus that supplies the arm. The nerve plexus passes through the armpit and can usually be anesthetized quickly with the aid of an ultrasound device.

General anesthesia is very unusual for carpal tunnel syndrome surgery and is usually used when the patient feels very anxious about the procedure.

The operation can be performed open or endoscopically. With the open surgical technique, the surgeon has a direct view of the surgical field. First, a small skin incision is made approximately in the middle of the palmar side of the wrist. Palmar means “facing the palm.”

The incision runs along the wrist and is about 3 cm long. The surgeon must be careful not to cut too far on the thumb side or too far on the little finger side in order not to injure essential nerves. Caution is particularly crucial on the small finger side, as this is where the so-called Guyon’s box is located.

This is an anatomical area, a box in which the critical ulnar nerve is located. It supplies muscles of the hand and the skin partly sensitive. In principle, the surgeon can vary the incision technique during the operation; e.g., there is also the short incision technique. In the end, however, the ligament that delimits the carpal tunnel hollow-handed and spans the carpal bones must be cut in every operation.

This ligament is called retinaculum musculorum flexor. The severing of the ligament leads to an immediate relief of pressure in the carpal canal and, consequently, to a recovery of the compressed median nerve, provided the damage has not progressed too far. No further surgical measures on the nerve itself are necessary. This operation is a routine procedure for hand surgeons, which usually proceeds without complications.

In the endoscopic procedure, the surgeon has an indirect view of the surgical field. He sees it through the endoscope. The course of the operation is the same as with the open technique. However, this procedure seems to be more comfortable for the patient due to less scar pain. On the other hand, there may be higher complication rates.

How long the surgical treatment of carpal tunnel syndrome takes depends on many factors. On the one hand, the procedure and experience of the doctor play a significant role. On the other hand, the individual anatomical conditions of the patient are always necessary. In general, an uncomplicated carpal tunnel syndrome operation hardly takes more than a few minutes. Once the surgery is completed, the patient remains in practice for some time for observation.

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Complications

In general, complications that can generally occur during surgery, such as post-operative bleeding and infections, are quite rare. In sporadic cases, a so-called algodystrophy may occur, which is characterized by severe pain. Too small skin incisions can lead to complications during the operation, as the ligament to be separated (Retinaculum musculorum flexor) cannot be completely split.

Also, the risk of complications is higher in endoscopic procedures than in open surgical techniques. On the other hand, the scars heal faster. It may also be necessary to switch to an open method during an endoscopic procedure due to complicated anatomical conditions. Overall, however, these are operations with low risks and few complications. Long-term success is also outstanding. Most patients are very satisfied to complain about free after the surgery. The more other diseases, such as diabetes, rheumatism, or arthrosis, the worse the outcome of the operation.

In the case of pain, pain-relieving medication can be taken. Cooling also helps against swelling and pain. The hand should not be wholly immobilized but moved slightly to avoid joint stiffness. Overloading and heavy physical activity should be avoided for the first few weeks, however.

Once the operation has been performed, the patient remains in practice for some time for observation, for example, to rule out the side effects of the anesthetic. Since the impact of the anesthesia can last up to several hours, depending on the type of anesthesia chosen, it is not advisable to go home alone or even to drive a car afterward. Besides, unproblematic healing of the surgical wound is only guaranteed if the hand is spared for the next 7-10 days, so that for this reason, too, independent driving is not recommended for the time after the operation.

As with all operations, scarring problems can occur. Besides, there may be a reduction in strength in the first six months after the surgery. In the rarest cases, there is a possibility of algodystrophy developing. This algodystrophy includes both motor and sensitive disorders.

Homeopathic treatment

Homeopathic healing approaches exclude conventional medical treatment for carpal tunnel syndrome per se. Patients there are often advised against surgery and advised to use alternative methods such as massage, acupuncture, and treatment by a chiropractor.

In general, there is nothing wrong with massage, but acupuncture or treatment by a chiropractor can also alleviate the symptoms. However, it is questionable whether such methods are effective, especially in cases of advanced nerve compression. They cannot permanently eliminate the cause of the compression, namely the bottleneck in the carpal tunnel.

Risk factors of carpal tunnel syndrome

To be able to make a detailed diagnosis, the patient must explain all his or her complaints to the doctor. Questions about accompanying diseases, such as diabetes mellitus (“diabetes”), malfunctions of the thyroid gland, or fractures in the area of the wrists, are also important.

Course of the disease

In the course of the disease, it is not only the nightly pain and discomfort that remains. Increasingly, the symptoms also occur during the day. Patients often report “clumsiness” and sudden “weakness” of the hand. The sensitivity of the skin on the thumb, index, middle, and ring fingers is increasingly reduced. In the subsequent stages, the thumb ball muscles may be lost. Fortunately, the complete loss of skin sensitivity in hand occurs very rarely nowadays.

Gender distribution

The gender distribution is about 75: 25 (female: male), mostly the primary working hand, is affected. In the majority of cases, both hands are affected. This does not mean that carpal tunnel syndrome must occur simultaneously in both hands. Often the disease, on the other hand, only occurs after years.

Carpal tunnel syndrome during pregnancy

During pregnancy, water retention at narrow anatomical points, such as the carpal tunnel, can lead to compression. The woman’s body is exposed to a special hormonal situation. Especially in the last trimester (third) of pregnancy, the body stores more water. The stored water causes the body tissues to swell, and compression of structures such as nerves can occur, especially in anatomical constrictions. The carpal tunnel is such an anatomical constriction.

This leads to a compression of the median nerve and the typical symptoms of carpal tunnel syndrome. Pain in the affected hand dominates, which can radiate into the arm and is particularly distressing at night. As a result, a lack of sleep and nocturnal restlessness develops. Besides, the middle finger and index finger, in particular, feel numb.

How is carpal tunnel syndrome in pregnancy to be treated? In principle, unnecessary interventions during pregnancy should be avoided. However, carpal tunnel syndrome can also be operated on during pregnancy, thanks to modern anesthetic procedures.

However, it is not necessarily sensible to do this. In most cases, the syndrome recedes as soon as the cause no longer exists. This means that after birth and possibly breastfeeding, the symptoms subside entirely in about 50% of those affected. It should, therefore, be attempted to wait for the birth. A night splint can be worn, especially if there is pain at night.

This is intended to relieve the symptoms so that the pregnant woman can sleep as free of complaints as possible. The splint relieves pressure in the carpal tunnel.

Above all, waiting for the operation prevents an infection during pregnancy. Even if the risk is quite low, an infection can occur during the surgery, the treatment of which can then be considerably complicated by the pregnancy. This is because not all medications may be given during pregnancy, which means that they are contraindicated. After weaning, an operation can, in principle, be performed at any time. However, it should be ensured that someone takes care of the baby for the first 2-3 weeks after the operation.

This includes changing diapers and bathing the child. During these activities, the fresh surgical wound can be contaminated with germs. This causes inflammations and infections. This should be avoided in any case.

Summary

Carpal tunnel syndrome is a “nerve entrapment” of the hand. If you look at the hand at the wrist level, you can see a wide band stretching between the ball of the thumb and the ball of the little finger, directly above the wrist. This band represents the roof of a canal, namely the carpal tunnel. This channel contains, among other things, an important nerve of the hand – the median nerve. In carpal tunnel syndrome, this channel is too narrow and it puts pressure on the median nerve.

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