What is carpal tunnel syndrome?

Carpal tunnel syndrome is one of the most common musculoskeletal disorders (MSDs). According to figures from Ameli.fr, each year in France, it is the source of 130,000 surgical operations.

SUMMARY :

What is carpal tunnel syndrome?
What are the causes and risk factors of carpal tunnel syndrome?
What are the symptoms of carpal tunnel syndrome?
How is the diagnosis made?
Treatments for carpal tunnel syndrome
How to relieve the symptoms?
Who and when to consult?

What is carpal tunnel syndrome?

THE carpal tunnel is a tunnel located at the base of the hand, on the side of the palm, at the level of the wrist. It contains the flexor tendons of the fingers and the median nerve of the hand.

Carpal tunnel syndrome refers to the set of symptoms resulting from compression of the median nerve inside the tunnel.

What are the causes and risk factors of carpal tunnel syndrome?

Mechanical causes

“Carpal tunnel syndrome occurs in people who use their hand a lot. The tendons swell, which reduces the place of the median nerve inside the tunnel. The problem in this case is mechanical, there is no longer enough room for tendons and nerves”, explains Dr. Frédérique Mazodier, orthopedic surgeon.

Due to repetitive tasks, intensive use of the hands, carpal tunnel syndrome is recognized as an occupational disease. According to public health France, “it is the 2nd pathology recognized as an occupational disease with, for the general social security scheme, 12,289 recognitions as an occupational disease having given rise to a first compensation in 2019. However, the under-declaration of an occupational disease was estimated in 2015 at 43%”.

Hormonal causes

“Hormonal variations can also be the cause of carpal tunnel syndrome. In this frequent case in women, it occurs during pregnancy, postpartum, before, during and after menopause. It is also found in the context of hormonal diseases, such as hyper or hypothyroidism”, details Frédérique Mazodier.

Very often finally, the carpal tunnel syndrome is idiopathic – no cause is identified.

Much more rarely, constitutional or acquired abnormalities are involved, such as a naturally narrow carpal tunnel, notes the Ameli.fr health insurance site.

What are the symptoms of carpal tunnel syndrome?

Tingling, numbness, pain, sensory disturbances and decreased strength are all symptoms of carpal tunnel syndrome.

“When a nerve is crushed, any nerve, it sends back to the brain erroneous information: pain, a burning sensation, the feeling of having your hand in a vice… The most classic symptom is numbness in the the first three fingers of the hand, the thumb, the index and the middle finger. At the beginning of the disease, these symptoms appear especially in the second part of the night and on waking”, says the orthopedist.

Evolution of carpal tunnel syndrome. Symptoms get worse except in the case of acute carpal tunnel syndrome. “After a very intense manual activity, you can have pain for several days and it disappears spontaneously. But in the vast majority of cases, it is a chronic pathology with symptoms that intensify”, notes Frédérique Mazodier. From unpleasant sensations in the morning, to nocturnal awakenings, people end up have symptoms all the time.

How is the diagnosis made?

The diagnosis is primarily clinical. “We examine the patients and during the interrogation we find tingling, numbness, pain, arm fatigue, reduced strength… So many symptoms that wake patients up at night”, explains the professional.

“L’electromyogram confirms that the compression is indeed at the wrist and not in the neck, on the cervical spine, which gives exactly the same symptoms at the level of the fingers”, explains Frédérique Mazoyer. This examination also makes it possible to know more precisely the level of damage to the nerve, by measuring the speed of the nerve impulse at the level of the carpal tunnel. It is also the result of this examination that will make it possible to choose the appropriate treatment.

Treatments for carpal tunnel syndrome

Carpal tunnel syndrome, how is it treated? In which cases are infiltrations indicated? If there is not too much damage to the electromyogram, for the beginning forms of the pathology, an infiltration can be proposed: “It’s about a injection of corticosteroid derivative above the wrist to deflate the tendons. This can be very effective but for a non-predefined duration. Some patients are relieved permanently, others very temporarily. For still others, it will have no effect.

The infiltrations can be carried out two to three times maximum “provided that the delays between each infiltration are long enough”.

When is surgery indicated? Surgical intervention is indicated when the damage to the nerve is too great and/or the infiltrations have not been effective. “It is a question of enlarging the carpal tunnel by opening the roof of the tunnel to make room for the tendons and the nerve. Several techniques exist: the tunnel can be opened from the outside by incising the palm of the hand. endoscopic technique consists of passing a camera through the tunnel and opening the roof of the tunnel from the inside. With this technique, you recover more quickly, there is no longer a scar in the palm of the hand, which is an area of ‘support”, develops the surgeon.

Tingling, numbness, pain… After the operation, which generally requires only local anesthesia, the vast majority of symptoms disappear instantly. “But you can always lack strength at the start for a variable time. Some nerves regenerate quickly and others more slowly”, explains Frédérique Mazodier.

According to Ameli.fr, the work stoppage after an operation can range from 15 days for a sedentary activity to 45 days for a position that requires significant physical commitment, in particular of the hand.

In the case of an infiltration, recurrence is possible but not after an operation. “Once we have made room, there is no risk of recurrence. But this pathology is often bilateral and does not appear at the same time on each hand”.

How to relieve the symptoms?

“Wearing a straight wrist splint avoids sleeping in positions where the wrist is hyperflexed or hypertensive. This relieves but obviously does not treat the syndrome”, notes the doctor.

Put the ailing hand to rest is also a good way to relieve symptoms but it is difficult to observe when the cause of the syndrome is related to the patient’s professional activity.

Who and when to consult?

“If there are no reasons that explain the occurrence of symptoms, you should consult as soon as possible because the pathology becomes chronic and worsens”, recommends Frédérique Mazoyer. Several specialists can be consulted, the general practitioner first, then the rheumatologist for the infiltrations and the orthopedic surgeon for the operation.

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