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Carpal tunnel syndrome
The median nerve runs through the carpal tunnel, a canal in the wrist that is surrounded by bone on three sides, and a fibrous sheath (the flexor retinaculum) on the other. As well as the nerve, many of the hand's tendons pass through this canal. The median nerve can be compressed by swelling of the contents of the canal, or by direct pressure from part of a broken or dislocated bone.
The syndrome is much more common in women than it is in men.
The first symptoms usually appear at night. Symptoms range from a burning, tingling numbness in the fingers (especially the thumb and the index and middle fingers) to difficulty gripping, making a fist, or dropping things.
Some cases of carpal tunnel syndrome are due to work-related cumulative trauma of the wrist. It is commonly caused by strain placed on the hand, for instance gripping and typing, which are usually performed repetitively in a person's occupation.
There are a number of causes of carpal tunnel syndrome. They can be either traumatic, or non-traumatic.
Traumatic causes include:
- Fractures of one of the arm bones, particularly a Colles' fracture.
- Dislocation of one of the carpal bones of the wrist.
- Hematoma forming inside the wrist, because of internal haemorrhaging.
- Deformities due to abnormal healing of old bone fractures.
Non-traumatic causes, generally happen over a period of time, and are not triggered by one certain event. Examples include:
- Tenosynovitis, which is inflammation of the joint. Part of the process of inflammation is swelling, and this compresses the nerve.
- With pregnancy and hypothyroidism, fluid is retained in tissues, which swells the joint.
- Acromegaly, a disorder of growth hormones, compresses the nerve by the abnormal growth of bones around the hand and wrist.
- Tumours (though not necessarily cancer), such as a ganglion or a lipoma, can protrude into the carpal tunnel, reducing the amount of space.
- Diabetes, rheumatoid arthritis, and obesity tend to cause swelling, thus decreasing the amount of space in the carpal tunnel.
- Idiopathic causes, which no-one can explain, can also cause this disease.
Carpal tunnel syndrome can be caused by improper posture during repetitive activities such as:
- Motorcycle riding (too much pressure on palms)
- Playing of musical instruments
Proper attention to ergonomic considerations can reduce or eliminate these kinds of injuries.
Tinel's sign is a way to detect irritated nerves. It is performed by lightly banging (percussing) over the nerve to elicit a sensation of tingling or "pins and needles" in the distribution of the nerve. In a person with carpal tunnel syndrome where the median nerve is compressed at the wrist, Tinel's sign is often "positive" and causes tingling in the thumb, index, and middle fingers. Tinel's sign is sometimes referred to as "distal tingling on percussion" or DTP.
Phalen's maneuver is another test for carpal tunnel syndrome. The patient is asked to keep their wrist at the extremity of flexion for 30 seconds. The aim is to compress the carpal tunnel and thus elicit the characteristic symptoms of the carpal tunnel syndrome. If the patient experiences a burning, tingling or numb sensation over the thumb, index, middle and ring fingers, then the test is positive. Phalen's maneuver is more sensitive than Tinel's sign.
In general, if a specific action or movement (such as typing on a keyboard, or gripping a hammer) is causing pain, then simply avoiding this action may be enough to alleviate symptoms. Unfortunately, this doesn't always work and a person's job may preclude simply stopping.
Carpal tunnel syndrome is treated by immobilizing the wrist in a splint to minimize or prevent pressure on the nerves (the use of splints for anything other than a short time is considered by many to be non productive).
If that fails, patients are sometimes given anti-inflammatory drugs or injections of cortisone in the wrist to reduce the swelling.
Carpal tunnel syndrome can also be treated non-surgically through the use of Active Release Techniques . The purpose of this treatment is to reduce the scar tissue adhesions, increase muscle elasticity, and increase strength.
There is also a surgical procedure in which doctors can open the wrist and cut the ligament (the flexor retinaculum ) at the bottom of the wrist to relieve the pressure. However, only a small percentage of patients require surgery. The surgery itself is very brief, and only a local anaesthetic is needed. Full recovery however, can take up to three months. This surgery can also be done endoscopically.
Long Term Recovery
Approximately 1 percent of individuals with carpal tunnel syndrome develop permanent injury. The majority recover completely and can avoid reinjury by changing the way they do repetitive movements, the frequency with which they do the movements, and the amount of time they rest between periods when they perform the movements.
- Carpal Tunnel Syndrome treatment treatment with Active Release Techniques
- Conquering Carpal Tunnel Syndrome book review
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