Carpal Tunnel Syndrome

What is it?

Carpal tunnel syndrome (CTS) is a condition where the median nerve is compressed at the wrist in a location called the carpal tunnel. Conditions like this are frequently referred to as "trapped" nerves. The compression of the nerve affects the blood supply to the nerve and also the flow of nutrients and structural elements within the nerve. This results in symptoms.

The carpal tunnel is formed by a broad ligament and the bones of the wrist on the palm side of the wrist. The median nerve provides for sensation to the thumb, index, middle and half the ring finger. It also provides function to the muscles of the fleshy pad at the base of the thumb. These muscles control the dexterity and mobility of the thumb.

Cause

In most cases there is no specific cause for the compression of the nerve . In a small proportion of cases the following causes may be underlying:-

• hypothyroidism (under active thyroid gland)
• fracture or ligament injury of the wrist recent or previously
• tenosynovitis (inflammation and swelling of the lining of the tendons at the wrist) such as occurs in rheumatoid arthritis
• pregnancy
• diabetes
• swellings within the carpal tunnel such as a ganglion.
• along with hand-arm vibration syndrome (HAVS)

Symptoms

There are typical symptoms of carpal tunnel syndrome, however not everybody with carpal tunnel syndrome gets all these symptoms.

Tingling of the fingers

Tingling of the fingers is experienced by some people as "pins & needles" or a "buzzing" or warmth of the affected fingers. The fingers affected  in carpal tunnel syndrome are commonly the middle and  index fingers. The thumb and ring finger can also be affected. The little finger does not get these symptoms as it is supplied by a different nerve.

The tingling may not be there all the time. It may occur after use of the hand or may also occur when the hand is not moved for sometime, such as when driving or holding a newspaper. It is also frequently experienced at night when asleep, and waking the person up. Patients with this frequently describe either having to hang the hand out of bed or shaking the hand to get the feeling back to normal.

If the tingling is constantly present, you should see your GP for a referral to a hand surgeon sooner as potentially the function of the nerve is at risk for permanent damage.

Numbness of the fingers

This affects the same fingers as the tingling. The numbness result in difficulty with manipulating small objects such as doing up buttons. Typically it tends to be also at night along with the tingling. It may also be on waking first thing in the morning.

The numbness may not be there all the time. If the numbness is constantly present, you should see your GP for a referral to a hand surgeon sooner as potentially the function of the nerve is at risk for permanent damage.

Pain

Pain in the hand and wrist is also frequently present. 

Muscle wasting

Loss of bulk in the fleshy pad at the base of the thumb may be noted in late stages. If you have tingling or numbness with this muscle wasting you should seek urgent referral from your GP to a hand surgeon.

Other symptoms

Frequently dropping objects when you think you have a grip of them is seen in CTS. Cramps of the muscles in the fleshy pad at the base of the thumb may also be described. Aching pain or discomfort in the forearm from the wrist upwards is also experienced.

Diagnosis

In the majority of cases the history of symptoms and an examination is sufficient to make the diagnosis. In some cases, additional investigations may be required such as an electrodiagnostic test (nerve conduction study with electromyography/EMG). The need for this test is usually decided by Mr Miranda once he has seen you. It is done when there are atypical symptoms or if there is a possibility of another nerve compression. Blood tests or X-rays may also be required if underlying causes are suspected.

Treatments

Non-surgical Treatment

In some cases a wrist splint for night time use may be helpful in reducing or abolishing the night time symptoms.

A steroid injection may also used to treat or make a diagnosis of carpal tunnel syndrome. Many GP's do perform steroid injections for CTS. However, if your symptoms of numbness or tingling are permanently present it may NOT be advisable to have a steroid injection, as a delay in surgical treatment could result in permanent nerve damage. Research studies have shown that in the majority of cases the effectiveness of steroid injections do not last more than a year.

If CTS occurs during pregnancy, simply waiting for the completion of the pregnancy or temporary use of a splint is all that may be required. 

When there are underlying causes such as rheumatoid arthritis, diabetes or hypothyroidism, the treatment or optimal control of these conditions may itself relieve the symptoms of CTS.

Surgical Treatment

The operation for this condition is carpal tunnel decompression (CTD). It is a long established operation first described in 1933. However in the 1950's a surgeon called Phalen raised the awareness of this condition and it's treatment with CTD  among the medical community. It is the most commonly performed operation that a hand surgeon does.

The operation is done under local anaesthetic in the majority of cases. To release the compression of the nerve the ligament of the carpal tunnel is cut. This ligament will heal in a few months.

If the symptoms are intermittent before the operation, the symptoms may be relieved within a few weeks of the operation. In other cases, it may take a few months for relief of the symptoms after the operation. The scar may take a about 6 to 8 weeks to stop being tender. Return to full grip strength may also take a similar time. In some cases, the symptoms never completely go away due to permanent damage to the median nerve present before the operation. 

Mr Miranda will go through in detail with you about the return to your usual recreation and occupation duties as everyone's circumstances are different.