Carpal tunnel syndrome usually presents as numbness +/- pain in the hand and forearm. The symptoms usually occur at night but as the disease progresses may give symptoms during the day.
The problem is due to compression of the median nerve as it passes across the wrist into the hand. The nerve passes through a tight tunnel formed by bones on the back and a strong ligament on the front. If the tunnel is too tight, for whatever reason, the nerve becomes unhappy and starts to complain. This nerve usually supplies movement to the thumb muscles and feeling to the thumb, index, middle and half of the ring finger. The symptoms usually start with numbness in this distribution followed by weakness in the thumb. Patients may complain of difficulty gripping wide objects or frequently dropping things. The muscles at the base of the thumb may also start to appear wasted.
The diagnosis is often confirmed by a nerve conduction test. This measures how well the median nerve is working and also confirms at what level is the problem.
Mild carpal tunnel syndrome can be managed with a wrist splint worn at night or via injections into the wrist. Surgery is indicated for more severe symptoms or for those that have failed the more conservative measures.
Surgery is performed as a day case procedure under local anaesthetic +/- sedation. An incision is hidden in one of the creases that runs in the palm of the hand and the tight ligament compressing the nerve is divided. The skin is then closed with dissolving sutures and the hand wrapped in a bandage. It is important to keep the hand elevated for the following week, keep the bandage dry and avoid strenuous use.
This operation allows the nerve more room to breathe and usually relieves the symptoms very quickly. Most people describe the previous aching and pain disappears immediately. If there was permanent numbness in the hand, it takes much longer for this to recover as it implies more significant damage to the median nerve.
Side effects and complications
There will be a permanent scar on the palm of the hand. This usually fades to a faint white line over the first 12 months. The scar may feel sensitive when pressed. The heel of the hand will also feel uncomfortable for several months. This is known as "pillar pain" and typically aches when putting force through the area (eg pushing yourself out of an armchair).
Rarely a nerve may be injured during the surgery, resulting in numbness or weakness in the hand.
Recurrence of the symptoms may occasionally occur due to scar tissue forming over the cut ligament.
2-3% of patients may develop pain and stiffness in the hand know as chronic regional pain syndrome (CRPS), following any type of hand surgery.