Carpal tunnel decompression

Carpal Tunnel surgery is a routine short procedure that involves decompressing the median nerve, which supplies sensation to the thumb, index and middle fingers and half of the ring finger. The motor branch of the nerve also activates some of the muscles at the base of the thumb.


Carpal tunnel decompression can be carried out under general anaesthetic or with local anaesthetic and sedation. The procedure is performed in a sterile theatre setting. A tourniquet is applied to the arm to stop blood flow in and out of the arm. This provides a very dry operating field with virtually no blood loss.

The carpal tunnel is formed by the small bones in the wrist which make up a concave shape. There is a strong ligament over the top of this concavity which creates the tunnel. The median nerve and all flexor tendons to the thumb and fingers pass through this tunnel.

The aim of surgery is to release the ligament over the top of the carpal tunnel in order to take the pressure off the nerve.

A small incision is made at the base of the palm. The ligament is identified and divided. This removes the pressure from the nerve and in most cases patients will experience a rapid improvement in their nerve pain and irritation.

In cases where patients may have had prolonged compression of the nerve, it may take some time for sensation to recover.


The wounds are closed with sutures which stay in place for the first two weeks. During this two week period, the wounds need to be kept clean and dry. Once the sutures have been removed, patients can start using the hand for lightweight day-to-day activities. It is still recommended that patients avoid strenuous gripping / lifting tasks for a further four weeks.

Some patients will experience tenderness around the surgical site and there may be some discomfort felt at the base of the thumb region. This usually settles over time but it may be a little uncomfortable for the patient to push against in the early stages.


Every operation has some element of risk associated with it. The anaesthetist will be happy to discuss the specific risks associated with the anaesthetic. There is always a potential for infection when the skin is opened. This risk is in the order of 1%.

Some patients may experience swelling around the median nerve which can result in some altered quality of  sensation in the early post-operative phase. The tourniquet is very tight during the operation, and some patients may experience a sensation of heaviness or a feeling of bruising in the upper arm after the procedure.

In appropriate patients, the surgery has a high success rate in relieving carpal tunnel symptoms.  

Related Information

Carpal Tunnel Syndrome