Carpal Tunnel Syndrome

Carpal tunnel syndrome: short overview

• Description: Narrowed carpal tunnel in the wrist exerts pressure on the middle arm nerve
• Causes: long-term wrist overload, predisposition, rheumatism, injuries, water retention, diabetes, overweight, kidney weakness
• symptoms: Nocturnal falling asleep of the hand, sensations of discomfort, pain, later impaired function, paralysis, diminished sense of touch
• Diagnosis: Querying typical symptoms and possible risk factors, functional and pain tests, measurement of nerve conduction velocity
• Treatment: Nocturnal immobilisation by rail, cortisone treatment, if necessary, surgical extension of the carpal tunnel
• Forecast: complete healing with timely therapy, irreversible paralysis symptoms at delayed start of treatment possible

What is a carpal tunnel syndrome?

In a carpal tunnel syndrome, an important tendon compartment, the so-called carpal tunnel, is narrowed in the wrist. He then laces a nerve that provides for certain areas of the hand. Possible consequences are discomfort, pain and paralysis.

The carpal tunnel is formed by the carpal bones and a stabilizing connective tissue band. In the middle of it run some hand tendons as well as the middle arm nerve (median nerve). This runs from the shoulder over the upper and the forearm. In addition to two other nerves, he controls the muscle movements and allows the sense of touch of the hand.

Bottleneck in the wrist

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

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

Carpal tunnel syndrome: causes and risk factors

There are quite a few triggers for a carpal tunnel syndrome and various risk factors that increase the likelihood of it.

Narrow carpal tunnel: People who by nature have a narrower carpal tunnel are more likely to get sick. For this reason, women get a carpal tunnel syndrome about three times as common as men.

inheritance: Probably an innate anatomical bottleneck is also the reason why carpal tunnel syndrome is particularly common in some families.

Strains of the wrist: People who work physically are three to seven times more likely to be affected by carpal tunnel syndrome than people who do no physical work. Certain occupational groups are therefore particularly at risk. This includes all occupational groups that operate machines with high levels of vibration (for example jackhammers), as well as those whose wrist is permanently exposed to high levels of physical activity, such as upholsterers or farmers.

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

injuries: After an injury near the wrist, especially after a spoke fracture, a carpal tunnel syndrome may develop.

inflammation: Another possible cause is inflammation and swelling of the tendon sheath, which also lie in the carpal tunnel and then press on the nerve.

Rheumatism: Inflammations in the joints mainly affect rheumatic patients. Every second rheumatism develops a carpal tunnel syndrome. Often this is even the first sign of an incipient rheumatic disease.

Chronic kidney failure (renal insufficiency): In people who often have to dialysis because of kidney failure, a carpal tunnel syndrome can develop on the arm that connects to the dialysis machine (shunt arm).

Water retention: If more water is stored in the joints and thus thicken the ligaments, the space in the carpal tunnel is also reduced. There are different triggers for this:

• Hyperthyroidism or hypofunction
• diabetes
• overweight
• hormonal changes (pregnancy / menopause)

symptoms

At an early stage, sufferers often do not take carpal tunnel syndrome seriously. But the longer the nerve is trapped on the wrist, the more likely it will be permanently damaged. Therefore, you should already have the first signs of a carpal tunnel syndrome neurologically clarified.

Early symptoms

Nocturnal falling asleep of the hands: The typical sign of a carpal tunnel syndrome in the early stage is the nocturnal falling asleep of the fingers. In the beginning it usually suffices to relocate the hand. Later, very severe pain occurs, which can go up to the arm and shoulder. Those affected often wake up with painful fingers at night. In the morning the fingers are thick swollen and stiff.

Discomfort: The carpal tunnel syndrome usually announces tingling sensations on the palms. Later, they gradually expand on a part of the fingers.

The middle arm nerve supplies the insides of the thumb, the index and middle finger as well as the thumb side of the ring finger. There the classic symptoms can develop. The small finger-facing side of the ring finger and the little finger itself are not affected by a carpal tunnel syndrome because they are being supplied by another brachial nerve.

Pain: Pain initially only occurs after a special strain on the wrist. These include, for example, gardening, renovation or cleaning. At a later stage, the symptoms also occur quite suddenly without apparent cause (“spontaneous”).

Deteriorated touch, awkwardness: The sense of touch and sensation of the fingers worsen in a carpal tunnel syndrome. For example, sufferers may have difficulty buttoning a garment or picking up small items.

Carpal tunnel syndrome: symptoms in the later stages

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

Muscle loss on the thumb: A muscle of the thumb, which is controlled by this nerve, then gradually forms back. The result is a visible dent on the thumb pad (thumb ball atrophy).

Due to the muscle wasting of the thumb, its function is severely limited. This can restrict those involved in everyday work. For example, if the thumb can no longer be splayed, it is difficult for the patient to pick something up or grab a bottle.

At this stage, the nerve is already severely damaged. If therapy is started now, it is often too late – damage to the nerve can not be undone. Lifelong numbness in the palm and paralysis of the thumb can be the consequences.

Carpal tunnel syndrome: Symptoms on both hands?

Most of the symptoms develop sequentially on both hands. In between, however, may be months or even years.

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

Carpal tunnel syndrome: examinations and diagnosis

First step for diagnosing carpal tunnel syndrome is obtaining personal medical history (anamnesis). Among other things, the doctor interviews the patient about his symptoms and any risk factors such as physical work, previous illnesses and illnesses in the family.

Physical examination

As part of the physical examination of the doctor initially scans the artery of the ball of the thumb. So he checks whether the muscle has already regressed.

Daum function: The function of the thumb is also tested. The doctor asks the patient, for example, to include a bottle. Typical of a carpal tunnel syndrome is that the patient can not spread the thumb well or not at all.

Sensitivity: The doctor tests the sense of sensation by stroking the patient with a cotton ball over the palm of his hand. If it 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: This carpal tunnel syndrome test taps the skin over the carpal tunnel. If this causes pain and discomfort to the patient, this is a sign of a carpal tunnel syndrome.

Phalen maneuver: For this test, the patient has to put his hands together with the backs of his hands. The wrist is strongly bent. This intensifies the pain, which also speaks for a carpal tunnel syndrome.

Neurological carpal tunnel syndrome test

Of course, a carpal tunnel syndrome can only be diagnosed on the basis of a neurological examination.

In order to rule out other illnesses with similar symptoms, the doctor often also examines the elbow region and the neck and shoulder area. Also in these places, the middle arm nerve can be narrowed.

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

In some cases, an exact measurement with a surface ENG is not possible. This can be the case, for example, when the nerve is different than normal. For a needle ENG, small needles are then pricked directly into the vicinity of the nerve, with the aid of which the measurement takes place. That can hurt a bit. The investigation is relatively short. Subsequently, usually no further complaints occur.

Ultrasound, X-ray, MRI:Imaging procedures provide clues about the condition of the carpal tunnel and possible causes

• Ultrasound (ultrasonography): The ultrasound examination shows how narrow the carpal tunnel is.
• X-ray: With an X-ray examination, the doctor can check whether arthritic changes narrow the wrist.
• Magnetic resonance imaging (MRI): If the doctor suspects that a tumor could cause the symptoms, magnetic resonance imaging can provide information.

Carpal tunnel syndrome: treatment

Easier cases of carpal tunnel syndrome can be alleviated without surgery. For example, by restraining the affected hand overnight with a splint. If inflammation is the cause of the narrowing of the carpal tunnel, cortisone can help – in the form of tablets, sometimes as an injection.

When to operate

In some cases, a carpal tunnel syndrome requires surgery:

• if conservative treatment does not improve significantly within four weeks

• if the patient has severe pain at night
• if the numbness stops in the affected hand
• when the conduction velocity of the nerve is significantly reduced.

What happens during a carpal tunnel syndrome operation?

During surgery, the surgeon cuts the carpal ligament. This is a tight connective tissue structure that tightens over the lower part of the carpal via the carpal tunnel. He also removes tissue from the tendon compartment, which restricts the nerve. As a result, the nerve and tendons have more space again.

Endoscopic or open surgery?

The procedure can be performed endoscopically, ie by “keyhole surgery”. Then the cut runs discretely in the inner fold of the wrist. If this is not possible for anatomical reasons, surgery is open. The cut then runs in the longitudinal line of the hollow hand. Again, he is hardly noticeable later.

Carpal tunnel syndrome: disease course and prognosis

A carpal tunnel syndrome can develop in any human. Usually both hands are affected sooner or later. It is estimated that up to ten percent of the population has symptoms of a carpal tunnel syndrome. But not all cases require treatment.

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

In general, the symptoms progressively worsen over the course of the disease. In particular, they increase after heavy work such as gardening, renovations, machine work, but also during pregnancy and after injuries to the arm.

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

Early surgery, complete healing

If operated on time and successfully, the carpal tunnel syndrome can be completely cured. The pain usually disappears the day after the procedure. Mobility, the sense of touch and sensation, the patient must first train again.

Exercise hands after surgery

Be sure to do the recommended exercises regularly and have a neurologist monitor the healing process after surgery.

The healing process may take several months, depending on the severity of the condition.

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

Unable to work in case of 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 area of ​​the thumb. This can severely limit everyday and professional life and even lead to occupational disability in individual cases.

Be sure to consult a doctor at the first sign of a carpal tunnel syndrome. The sooner the treatment starts, the better the chances of recovery!

Additional information

Guideline

Guideline “Diagnosis and Therapy of the Carpal Tunnel Syndrome” of the German Society for Hand Surgery and the German Society of Neurosurgery e.V. (2012)