Carpal Tunnel Decompression

What is carpal tunnel syndrome?

There are three main nerves travelling down the arm to the hand.  One of these, the median nerve, is responsible for most feeling in the hand (apart from the little finger).  The median nerve travels through a narrow tunnel, the carpal tunnel, as it passes from the wrist into the palm of the hand.  If the carpal tunnel becomes too narrow, then pressure develops on the nerve.

Why does the carpal tunnel become narrow?

The carpal tunnel is naturally narrow.  As well as the nerve, a dozen or so tendons to the fingers of the hand pass through the same tunnel.  Any injury or inflammation to the tendons causes them to swell slightly. This can be enough to cause pressure on the nerve.  Most people with carpal tunnel syndrome are perfectly normal and healthy, but some medical conditions can cause swelling of the tissues in the carpal tunnel.  Pregnancy can offer trigger symptoms. 

What are the symptoms of carpal tunnel syndrome?

Usually the symptoms consist of either strong tingling in the hands, or pain in the hands, or both.  Sometimes the problem is numbness.  Often, only one hand is affected, or if both are affected, one is much worse than the other.  The symptoms are frequently intermittent, and typically bad at night.  It is not uncommon for sleep to be disturbed regularly, with little or no trouble during the day.  Often there is an ache in the forearm as well as the symptoms in the hands themselves.

How is carpal tunnel syndrome diagnosed?

The diagnosis is made on the basis of clinical findings, that is, what you report to your doctor.  Nerve conduction studies (often called EMG) are special electrical tests that study the function of the median nerve and other nerves.  This test is used to confirm the diagnosis and to give an indication of the severity of the effects on the nerve.

Why do I need surgery?

The main reason for surgery is to relieve the troublesome symptoms in your hands.  This is usually necessary if your sleep is being disturbed regularly.  Sometimes, surgery is needed because of wasting of the small muscles in the hand, which can cause loss of fine movement.  Surgery might also be needed to prevent permanent nerve damage, which can lead to permanent numbness and loss of function.

What happens during the operation?

The operation usually involves a local anaesthetic.  You will not be able to see the surgery.  A tourniquet is placed around your arm to prevent bleeding.  A short incision is made at the base of the palm.  The surgeon opens the carpal tunnel fully, through this incision, by cutting the ligament which forms the roof of the tunnel.  This does not weaken your hand.  Three or four stitches are then inserted and a padded dressing is applied.  The anaesthetic wears off after about four hours.

What is the success rate?

The success rate is well over 90 per cent.  Failure to adequately or fully relieve symptoms occurs in four-to-five-per cent of cases.  Less than one per cent of cases are made worse by surgery.  Complications are uncommon, but can occur.  Wound infection is an occasional problem and needs immediate attention.  Damage to the median nerve itself, causing severe numbness or some weakness in the hand, is very rare but possible.  Some people find the surgery effective in relieving the original symptoms but are troubled by a painful wound.  The scar can be quite tender for as long as several months.  If there is some degree of permanent numbness prior to surgery, then it is unlikely that surgery will completely relieve the symptoms.  In other words, some degree of numbness will remain.  As long as the numbness is intermittent, surgery will usually relieve the symptoms.

How long will I be in hospital?

Carpal tunnel decompression is a day procedure.  Admission to hospital is in the early morning with discharge by late morning or early afternoon.  Because of changes to health insurance rules, it is only appropriate to stay overnight if there is a specific medical need.

What can I expect after the operation?

Naturally, your wrist and hand will be sore for a few days, especially in the first 48 hours.  Keeping your hand elevated (on a pillow or two during the first night at home) will help. If you have been given a sling, you should only need it for a day or two, three at the most.  After that, it is better to discard the sling and use your arm naturally. You should keep your wrist straight as much as you can, until the stitches are removed.  You will have been given an appointment from 7 to 10 days after the operation, when the stitches will be removed and progress reviewed.  You can flex your fingers regularly (though not forcibly) even while your hand is still bandaged, but you should avoid getting your hand wet and avoid using it for heavy work until you have been reviewed.

Home