Carpal tunnel release surgery

What is the carpal tunnel?

The median nerve is one of the two main nerves in the hand. It provides sensation to the thumb, index, middle and part of the ring fingers. It also supplies minor muscles in the hand.

On its way to the hand, it passes through a tunnel made by the wrist bones (the carpus) and a ligament which forms the roof (hence 'carpal' tunnel). The nerve shares this space with the flexor tendons which are the main gripping tendons of the fingers.

When the lining of the tunnel or the sheaths of the tendons thicken, the nerve, which is the softest structure, is compressed and symptoms are felt in the area it supplies.

This leads to tingling in the fingers, later loss of feeling, some pain and often night symptoms when the hand wakes the patient because of unpleasant tingling and numbness.

What does treatment involve?

In the initial stages, the lining of the tunnel can be made to thin, by injections of a small dose of steroid. This increases the available space in the tunnel.

Splints can also be worn to relieve symptoms. The nerve is more pinched when the wrist is bent, therefore a splint prevents bending and thus relieves symptoms.

When these measures fail or if the condition is severe, surgery is the next option. This is called a carpal tunnel release and involves cutting of the ligament which is compressing the nerve. This is done through a small cut in the skin of the heel of the hand, close to the wrist. This has the effect of relaxing the tunnel.

Occasionally the surgery will need to be preceded by nerve conduction study, which is an investigation to map out the nerve and identify where, and how severely, it is being compressed.

This surgery is performed under local anaesthetic injection at the wrist, and is a short operation usually performed as an outpatient procedure, meaning you may not require an overnight stay.

When will I recover?

The cut in the hand is stitched up using sutures which are removed within two weeks. After this, your hand can return to full use.

Following the surgery, it is important to elevate the hand at all times for two weeks. A sling is provided but it need not be worn all the time as long as the hand is kept above the level of the heart. You must keep the fingers moving through their full range, straightening them fully and rolling them into a fist fully, and you must not use, or dangle, the hand.

The operation usually removes all related symptoms, particularly if these are of recent onset. Those who have had compression for a long time, or diabetic patients, may not resolve all symptoms.

The scar, in the heel of the palm, usually heals to a very fine, pale line but it may be tender for some weeks after surgery.

Recurrence of carpal tunnel syndrome, after effective surgery, is rare.