Carpal tunnel syndrome – causes and treatment

Carpal tunnel syndrome may require surgery if establishedCarpal tunnel syndrome (CTS) is one of the most common orthopaedic conditions affecting the hands. It is a condition which causes pain, paraesthesias (“pins and needles”) or even weakness in the hand. It specifically affects the thumb, index, middle and ring fingers although not all fingers are always affected. Both hands may be affected at the same time, and if established, may require surgery…

The Cause of Carpal Tunnel Syndrome

The median nerve is one of the main nerves to supply the hand and fingers. It is formed near the neck, and passes through the arm, forearm and then finally into the hand. In the hand it passes through a tight passage called the carpal tunnel before dividing into its final branches in the fingers. Anything which causes the space in this tunnel to become tighter may result in a squeezing of the nerve. This produces the symptoms of CTS. Sensation is usually affected first, resulting in the pain and altered sensation in the fingers. Power can also be affected, result in wasting of the muscles and weakness in the hand. This may become permanent if left untreated.

CTS is often associated with occupations that involve a lot of typing. it may also be caused by other activities that involve prolonged or repetitive flexion of the wrist.It may affect pregnant women due to fluid retention. Certain medical conditions such as diabetes affect the nervous system and may play a role in the development of the condition. Inflammation involving the wrist, (e.g. in rheumatoid arthritis), may cause a mechanical compression of the median nerve. Other conditions may also increase the risk. These include menopause, being overweight, thyroid disorders or kidney failure. In many instances, however, the cause is not established. Women are affected up to ten times more commonly than men. The condition is most prevalent between 45 to 60 years of age.

Symptoms and Signs

People with CTS commonly report numbness and tingling which affects the palm-side of the thumb, index, middle and ring fingers. Involvement of the little finger is not usual, and may point to a different or additional problem. The hand may “fall asleep” and there may be a tendency to lose grip or drop things.

The symptoms may come and go and are classically worse at night. It occasionally wakes a person from sleep, and is relieved by shaking the hand or wrist. Pain may be the main feature, usually felt at the wrist but may radiate to the fingers or even towards the elbow.

A person may report weakness or clumsiness of the hand. It is also possible to get a sensation of tightness, swelling or even changes in temperature and skin colour. These symptoms, however,  are not as common.

A thorough examination of the hand is performed but often there may be no abnormal findings. Sensation may be altered in the palm side of the thumb, index, middle and thumb-side of the ring finger. In severe and long-standing cases, the small muscles in the hand and thumb may be weak when power is tested. The muscle bulk may also be diminished.

The elbow, shoulder and especially the neck are usually examined. It is possible that conditions in these areas may cause symptoms similar to CTS.

Special Tests for Carpal Tunnel Syndrome

A number of special tests may be performed during the examination. These are used to aid the diagnosis although they are not always completely diagnostic. A tingling in the affected fingers with gentle tapping on the palm-side of the wrist over the nerve is a positive Tinel sign. A similar tingling or numbness may be reproduced after bending the wrist as much as possible for at least 60 seconds (positive Phalen sign). This may be positive even after simply applying direct pressure on the wrist over the nerve for at least 30 seconds.

Further Investigations

The diagnosis of carpal tunnel syndrome is often made clinically and without the need for further tests. This is the case if the history and examination are highly suggestive and the Tinel and/or Phalen signs are positive. Blood tests and X-rays are usually not needed, unless another diagnosis is being considered. On occasion, an ultrasound scan or MRI may be necessary if it is thought that there may be a “space-occupying lesion” in the carpal tunnel causing the symptoms. An example of this is a ganglion (fluid-filled cyst),

The most commonly requested test in doubtful or atypical cases is a nerve conduction study (electrophysiologic testing). This investigation may confirm the diagnosis and categorise the condition as mild, moderate or severe. This test also helps to ascertain if the symptoms might be present as a result of a compression at the level of the neck, as opposed to the wrist.

Treatment

The first steps to curing CTS would naturally involve correcting any contributing factors and making certain lifestyle modifications. This includes losing excess weight and increasing aerobic exercise. Anti-inflammatories may be used in those in whom wrist inflammation is causing the symptoms. The use of a splint worn mainly at night which keeps the wrist slightly extended for a period of at least three weeks may provide benefit in mild cases.

If the symptoms persist, consideration can be given to an injection of cortisone (a strong anti-inflammatory) into the carpal tunnel. This is useful in a pregnant woman where the CTS is expected to resolve after the pregnancy. The injection can be done in the doctor’s rooms and does not require admission to hospital.

Surgery for Carpal Tunnel Syndrome

If conservative interventions fail or if the CTS is severe, surgery is indicated. The operation is done as a day case – the patient does not need to spend the night in hospital. Modern anaesthetic techniques allow for the procedure to be done safely and comfortably under local anaesthetic and sedation to avoid having a general anaesthetic.

The operation itself involves a small cut on the palm of the hand, just beyond the wrist, although some surgeons prefer to perform the procedure endoscopically (through “keyhole surgery”). The tight ligament over the nerve is cut through. The tension on the nerve is thereby released. A splint may be applied for a few weeks after surgery. In most instances it is not necessary to take extended leave from work. Driving and writing is possible even while wearing a splint.

Most activities can be resumed soon after the operation. Strenuous exercise and heavy lifting should be avoided for at least six weeks.

For an in-depth description on what carpal tunnel surgery involves, please read: Performing surgery for carpal tunnel syndrome.

The success rate of the procedure is high and often patients experience resolution of symptoms immediately after surgery. The potential risks involved are small. Injury to the median nerve is possible, as is infection and excessive bleeding. In the majority of patients the condition does not recur, but this is certainly possible. If it recurs the patient may require another operation.

Summary

Carpal tunnel syndrome is a common but very treatable condition. The results of surgery are good and complications are low.

As an orthopaedic surgeon, I see and treat many patients who have carpal tunnel syndrome. I treat patients at Waterfall Hospital in Waterfall/Midrand and Morningside Mediclinic in Sandton. I also treat patients from many other areas as well, including Rosebank, Sunninghill and Fourways.

Yours in good health,

Dr Warren Matthee

MB BCh (Wits), MRCS (England), MMed (Ortho Surg), FC Orth (SA)

Orthopaedic Surgeon

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