Carpal tunnel syndrome: description, causes, operation

Carpal tunnel syndrome: description, causes, operation

Carpal tunnel syndrome is caused by a bottleneck in the tendon compartment of the wrist. This causes the median arm nerve, which supplies various areas of the hand, to become pinched. The hand falls asleep and the patients suffer from numbness, sensations, pain, later paralysis and dysfunction.

Read here what carpal tunnel syndrome is exactly, how it develops and how it can be treated.

carpal tunnel syndrome, Carpal tunnel syndrome: description, causes, operation

Carpal tunnel syndrome: short overview

  • Description: constricted carpal tunnel in the wrist exerts pressure on the median arm nerve
  • Causes: long-term overstraining of the wrist, predisposition, rheumatism, injuries, water retention, diabetes, overweight, kidney weakness
  • Symptoms: falling asleep of the hand at night, sensations, pain, later functional limitations, paralysis, reduced sense of touch
  • Diagnostics: Queries of typical symptoms and possible risk factors, function and pain tests, measurement of nerve conduction velocity
  • Treatment: nightly immobilization by splint, cortisone treatment, if necessary surgical widening of the carpal tunnel
  • Prognosis: complete healing with timely therapy, irreversible paralysis possible with delayed start of treatment

What is carpal tunnel syndrome?

In carpal tunnel syndrome, an important tendon compartment, the so-called carpal tunnel, is narrowed in the wrist. It then constricts a nerve that supplies certain areas of the hand. Possible consequences are paraesthesia, pain and paralysis.

In theory, anyone can get carpal tunnel syndrome. In fact, however, it is predominantly women of advanced age, usually after the menopause. This is because the nerve shares a channel with tendons, tendon sliding tissue and fatty tissue. And this can swell due to hormonal factors. The nerve is the weakest participant in the channel and is most likely to be pressed. This then causes the typical complaints, which one should also urgently follow up.

For the diagnosis it is important what the patient describes. In addition, I send almost every patient to a neurologist. He measures the nerve conduction velocity and performs nerve tests to determine where the problem lies. The nerve may also be trapped at the shoulder, for example – but this is much more difficult to treat than carpal tunnel syndrome. Patients are often free of complaints after treatment.

There are also conservative methods, such as immobilizing the hand at night or taking cortisone. In the long term, however, only one operation will help. There are patients who report an improvement without treatment – but usually this is not a good sign. The nerve causes less discomfort because it conducts even worse. Therefore my advice: It is better to have a checkup by a neurologist sooner rather than later and then have surgery. Nerves do not forgive damage!

The carpal tunnel is formed by the carpal bones and a stabilizing connective tissue band. In its center run some hand tendons as well as the median arm nerve (nervus medianus). This runs from the shoulder over the upper and lower arm. In addition to two other nerves, it controls the muscle movements and enables the hand’s sense of touch.

Wrist pinch

If the tunnel narrows, the nerve is stressed and irritated by the pressure. Then the typical symptoms of carpal tunnel syndrome appear, such as numbness, pain and later even paralysis.

The problem is that the first signs of carpal tunnel syndrome, such as falling asleep at night, tingling and slight discomfort, are often not taken seriously. Some affected people only go to the doctor when permanent damage has already occurred.

Carpal tunnel syndrome: causes and risk factors

There are a whole range of triggers for carpal tunnel syndrome and various risk factors that increase the likelihood of it occurring.

Narrow carpal tunnel: People who have a rather narrow carpal tunnel by nature are more likely to fall ill. For this reason, women get carpal tunnel syndrome about three times more often than men.

Heredity: Probably a congenital anatomical constriction is also the reason why carpal tunnel syndrome is particularly common in some families.

Stress on the wrist: People who work physically are three to seven times more likely to suffer from carpal tunnel syndrome than those who do not do any physical work. Certain occupational groups are therefore particularly at risk. This includes all occupational groups that operate machines with strong vibrations (e.g. pneumatic hammers), as well as those whose wrists are exposed to a permanently high load through movement, such as upholsterers or farmers.

Recent studies have shown that 50 percent of female cleaners also develop carpal tunnel syndrome. People who work a lot with computers are not among the most vulnerable professional groups.

Injuries: After an injury near the wrist, especially after a broken spoke, carpal tunnel syndrome can develop.

Inflammation: Another possible cause is inflammation and swelling of the tendon sheaths, which are also located in the carpal tunnel and then press on the nerve.

Rheumatism: Inflammations in the joints affect rheumatic patients in particular. Every second rheumatic patient therefore develops carpal tunnel syndrome. Often this is even the first sign of a beginning rheumatic disease.

Chronic kidney weakness (renal insufficiency): In people who have to go on dialysis frequently because of kidney weakness, carpal tunnel syndrome can develop on the arm that is connected to the dialysis machine (shunt arm).

Water retention: If more water is stored in the joints, causing the ligaments to thicken, the clearance in the carpal tunnel is also reduced. There are various triggers for this:

  • Hyper- or hypothyroidism
  • Diabetes
  • Overweight
  • hormonal changes (pregnancy/menopause)


At an early stage, those affected often do not take carpal tunnel syndrome seriously. But the longer the nerve is pinched at the wrist, the more likely it is to be permanently damaged. Therefore, you should already have the first signs of carpal tunnel syndrome clarified neurologically.

Early symptoms

Nightly falling asleep of the hands: In the early stages of carpal tunnel syndrome, a typical sign of carpal tunnel syndrome is the nightly falling asleep of the fingers. In the beginning it is usually sufficient to move the hand around. Later, very severe pain occurs, which can extend up to the arm and shoulder. Those affected often wake up at night with sore fingers. In the morning the fingers are swollen and stiff.

Sensitivity: The carpal tunnel syndrome usually announces itself by tingling sensations in the palm of the hand. Later they gradually extend to part of the fingers.

The median arm nerve supplies the inner sides of the thumb, index and middle finger and the thumb side of the ring finger. There the classic symptoms can develop. The side of the ring finger facing the little finger and the little finger itself are not affected by carpal tunnel syndrome because they are supplied by another arm nerve.

Pain: Pain initially only occurs after a particular strain on the wrist. This includes gardening, renovating or cleaning. At a later stage, the complaints also occur suddenly without any apparent reason (“spontaneously”).

Deteriorated sense of touch, clumsiness: The sense of touch and the sensitivity of the fingers also deteriorate in carpal tunnel syndrome. Those affected then have difficulty, for example, buttoning a piece of clothing or picking up small objects.

Carpal tunnel syndrome: symptoms in later stages

Loss of sensitivity: If the pressure on the nerves persists for a long time, they are increasingly damaged. Soon the unpleasant sensations in the fingers disappear. For this they become largely unfeeling. Later paralysis occurs.

Muscle loss at the thumb: A muscle of the thumb that is controlled by this nerve then gradually regresses. A visible dent at the ball of the thumb (thumb ball atrophy) is formed.

Due to the muscle atrophy of the thumb, its function is severely restricted. This can restrict those affected in everyday work. If the thumb can no longer be spread, patients find it difficult, for example, to pick up something in their hand or to grasp a bottle.

At this stage, the nerve is already severely damaged. If therapy is only started now, it is often already too late – the damage to the nerve can no longer be reversed. A life-long numbness in the palm of the hand and paralysis of the thumb can be the consequences.

Carpal tunnel syndrome: symptoms on both hands?

Usually the symptoms develop one after the other on both hands. However, months or even years can lie between them.

Since the dominant hand is more heavily loaded, carpal tunnel syndrome usually occurs first there – i.e. in right-handed people in the right hand. The symptoms are usually also more pronounced here than in the other hand.

Carpal tunnel syndrome: examinations and diagnosis

The first step in the diagnosis of carpal tunnel syndrome is to obtain a personal medical history (anamnesis). The doctor asks the patient about his symptoms and possible risk factors such as physical work, previous illnesses and cases of illness in the family.

Physical examination

As part of the physical examination, the doctor first palpates the ball of the thumb muscles. In this way he checks whether the muscle has already regressed.

Thumb function: The function of the thumb is also tested. The doctor asks the patient to hold a bottle, for example. Typical for carpal tunnel syndrome is that the patient is unable to spread the thumb well or at all.

Sensitivity: The doctor tests the patient’s sensitivity by stroking the palm of the hand with a cotton ball. If the latter does not perceive the touch, the surface sensitivity is disturbed.

Sense of touch: To test the sense of touch, the patient is given the task of picking up coins or paper clips.

Provocation tests

Hoffman-Tinel-Test: In this carpal tunnel syndrome test, the skin above the carpal tunnel is patted off. If this causes pain and discomfort for the patient, it is a sign of carpal tunnel syndrome.

Phalenic symbol: For this test, the patient must place the hands with the backs of their hands together. The wrist is strongly bent in the process. If the pain intensifies, this also indicates carpal tunnel syndrome.

Neurological carpal tunnel syndrome test

However, carpal tunnel syndrome can only be diagnosed with certainty on the basis of a neurological examination.

In order to rule out other diseases with similar symptoms, the doctor often also examines the elbow region and the neck and shoulder area. The median arm nerve can also be constricted at these points.

Electroneurography (ENG): With the help of electroneurography, the doctor can measure how quickly the central arm nerve transmits received stimuli and transfers them to a muscle. In a so-called surface ENG, electrodes are stuck to the skin. The conduction velocity of the median arm nerve is then compared with that of a healthy nerve. This examination is painless.

In some cases an exact measurement with a surface ENG is not possible. This can be the case, for example, if the nerve runs differently than normal. For a needle-ENG, small needles are then inserted directly into the nerve with the help of which the measurement is taken. This may hurt a little. However, the investigation is relatively short. Afterwards, there are usually no further complaints.

Ultrasound, X-ray, MRT: imaging techniques provide information on the condition of the carpal tunnel and possible causes

  • Ultrasound (sonography): The ultrasound examination can be used to determine how narrow the carpal tunnel is.
  • X-ray: With an X-ray examination, the doctor can check whether arthrosis-like changes narrow the wrist.
  • Magnetic resonance tomography (MRT): If the doctor suspects that a tumour could cause the symptoms, magnetic resonance imaging can provide information.

Carpal tunnel syndrome: treatment

Milder cases of carpal tunnel syndrome can be relieved without surgery. For example, by immobilizing the affected hand overnight with a splint. If an inflammation is the cause of the narrowing of the carpal tunnel, cortisone can help – in the form of tablets, sometimes also as injections.

When to operate

In some cases, carpal tunnel syndrome may require surgery:

  • if conservative treatment approaches do not achieve a significant improvement within four weeks
  • if the patient has severe pain at night
  • if the numbness in the affected hand persists
  • when the conduction velocity of the nerve is significantly reduced.

What happens during carpal tunnel syndrome surgery?

During the operation the surgeon cuts the carpal ligament. This is a firm connective tissue structure that stretches tightly over the lower part of the wrist via the carpal tunnel. He also removes tissue from the tendon compartment that constricts the nerve. This gives the nerve and tendons more space again.

Endoscopic or open surgery?

The operation can be performed endoscopically, i.e. by “keyhole surgery”. Then the incision is made discreetly in the inner wrist fold. If this is not possible for anatomical reasons, open surgery is performed. The incision is then made in the longitudinal line of the palm. Here too, he is hardly noticed later.

Carpal tunnel syndrome: course of disease and prognosis

Carpal tunnel syndrome can develop in anyone. Sooner or later both hands are usually affected. It is estimated that up to ten percent of the population has symptoms of carpal tunnel syndrome. However, not all cases require treatment.

Both the symptoms and the course of carpal tunnel syndrome can vary greatly from patient to patient.

In general, however, the symptoms worsen continuously in the course of the disease. In particular, they increase after heavy strain such as gardening, renovation work, machine work, but also during pregnancy and after injuries to the arm.

Less frequently, the symptoms caused by carpal tunnel syndrome remain constant over a longer period of time. Some patients have only moderate symptoms for years, interrupted by long symptom-free intervals. In such cases, the affected persons often go to the doctor late. The nerve is then usually already irreversibly damaged.

Early surgery, complete healing

If the operation is timely and successful, carpal tunnel syndrome can be completely cured. The pain usually disappears the day after the procedure. Mobility, the sense of touch and sensation must first be trained again by the patient.

Exercising hands after the operation

Make sure you do the recommended exercises regularly and have a neurologist check the healing process after the operation.

The healing process can take several months, depending on the severity of the disease.

Complications such as secondary bleeding and infection are rare in carpal tunnel surgery. However, in some cases further intervention is necessary.

Disabled with severe nerve damage

If the nerve is severely damaged, complete healing is no longer possible. The patients then suffer permanently from sensory disturbances in the hand and paralysis in the thumb area. This can severely restrict everyday and professional life and in individual cases even lead to occupational disability.

It is therefore essential that you see a doctor at the first signs of carpal tunnel syndrome. The earlier the treatment begins, the better the chances of recovery!

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Sandra Eades