What causes numbness in fingers while sleeping

Carpal tunnel syndrome: when fingers fall asleep at night

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DEFAULT: How is carpal tunnel syndrome noticeable?

Karle: Many adults have one without first realizing it. It usually starts with the fingers falling asleep mainly at night. There is an uncomfortable tingling sensation in all fingers with the exception of the little finger. As the disease progresses, numbness of the fingers and paralysis of the ball of the thumb may occur.

DEFAULT: What is the cause of this?

Karle: The metacarpal nerve runs in the area of ​​the wrist through a canal formed by the carpal bones and a tight ligament. There are also nine tendons in this canal. If, for example, the tendon sheaths swell, the nerve constricts.

DEFAULT: And does that cause pain?

Karle: Yes, because nerves don't give up easily when they are under pressure or when they are not well supplied with blood. You know that from toothache. The nerve repeatedly sends signals to the brain that are felt as tingling or pain.

DEFAULT: How does the tendon sheath swell?

Karle: There are different reasons for this. It often occurs in rheumatism or gout patients, with thyroid diseases or after heavy hand strain. But other causes, such as a ganglion in the course of the carpal canal or a poorly healed bone fracture in the area of ​​the wrist, can lead to a narrowing in the carpal canal. Even during pregnancy, more fluid is often stored, which can lead to swelling of the tendon sheaths.

DEFAULT: Are certain professional groups or athletes more affected?

Karle: Yes, carpal tunnel syndrome occurs more frequently in patients with high levels of strain or pressure in the palm of the hand, such as construction workers who work with jackhammers. Mountain bikers also experience this typical strain. Anyone who generally works a lot with their hands, puts a lot of strain on them, e.g. works a lot in the garden, can suffer from carpal tunnel syndrome - but they don't have to.

DEFAULT: How common is carpal tunnel syndrome?

Karle: Carpal tunnel syndrome is the most common nerve compression syndrome. About ten to 15 percent of the population are affected, women three times more often than men. Around three out of 1,000 people develop it anew each year.

DEFAULT: Does the syndrome affect both hands?

Karle: Both hands are affected in around half of the patients. Sometimes the problem is only with the dominant hand, as this is where the burden is greater.

DEFAULT: How is therapy carried out?

Karle: The first step is conservative therapy with a night positioning splint that keeps the wrist in a neutral position. In this position the width of the carpal tunnel is greatest. This splint should be worn for at least six weeks. This often provides initial relief for the patient, the tendon sheaths become swollen and the nerve is relieved.

DEFAULT: And that always helps?

Karle: No, only if the cause was temporary exposure. For many patients, conservative therapy is insufficient and the symptoms return after a while.

DEFAULT: And what happens then?

Karle: Patients with tingling sensations and pain at night should see a doctor early. They measure the nerve conduction velocity and, in some cases, do an ultrasound to see how narrow the nerve is and what could be the cause. An operation is then necessary in around two thirds of the cases.

DEFAULT: How does the operation work?

Karle: The procedure is usually carried out on an outpatient basis with local anesthesia. The bony floor of the canal is on the side of the back of the hand, a thick band of connective tissue on the side of the palm at the level of the wrist. During the operation, this ligament, which runs over the canal, is split using a small incision about one to two centimeters long. Sometimes an additional small incision is needed at wrist level or part of it is removed to prevent scarring. The procedure relieves the carpal canal and creates more space for the nerve. The actual operation time is 15 to 20 minutes. The costs are covered by the health insurance companies.

DEFAULT: What is the prognosis after the operation?

Karle: The prognosis after such a carpal roof split is very good. By relieving pressure on the nerve, patients are usually symptom-free from the first night. After two weeks the strings are pulled, and from this point on the hand can be used again in everyday life. The procedure should always be performed by an experienced hand surgeon. It is important that the operation is carried out early so that the nerve does not have permanent damage.

DEFAULT: When does permanent damage occur?

Karle: Permanent pressure on the nerve can damage it irreversibly. This often affects older patients or diabetics who have waited too long before the operation.

DEFAULT: What exactly happens if the operation is not performed or is operated too late?

Karle: This can lead to permanent numbness in the fingers or muscle paralysis, because the metacarpal nerve supplies the ball of the thumb, among other things, which is responsible for moving the thumb to the little finger. If you wait too long before the operation, this muscle shrinks and usually does not recover completely. This is why early detection of carpal tunnel syndrome is so important. (Bernadette Redl, 9.6.2019)