carpal tunnel syndrome
what is it?
The carpal tunnel is a narrow passage that lies at the front of the wrist and contains tendons,
and the median nerve. This nerve controls muscles which move the thumb and also carries
the “feeling” from the thumb and index, middle and half of the ring finger. In Carpal Tunnel
Syndrome (CTS) the median nerve is squeezed as it runs through the carpal tunnel; the
typical symptoms are described below.
who gets it?
Between 1 and 10% of the population will have some symptoms of CTS at some time in their
lives. CTS may occur at any age, but half of all cases appear in the fifth and sixth decade.
Females are affected more frequently than males.
what causes it?
CTS is caused by pressure on the median nerve. This pressure may be due to the carpal
tunnel being too small or its contents too swollen. In most the cause is unknown. Sometimes a
cause can be identified eg. rheumatoid arthritis; fluid retention (associated with periods and
pregnancy); underactive thyroid; diabetes and following wrist fractures. Certain activities, due
to the position the wrist is placed in, are associated with CTS; examples include: finger motion
with the wrist extended - eg. typing; playing certain musical instruments; weight-bearing with
the wrist extended - eg. individuals who are wheel-chair bound & cycling; wrist held bent
(flexed) for prolonged periods of time (awkward sleeping position).
what are the symptoms?
Typical symptoms of CTS are pain/aching and tingling or numbness in the hand. The
thumb,index and middle finger are usually affected; although the whole hand may feel dead.
Both hands may be affected. Weakness & clumsiness may be present, especially in long
standing cases. Symptoms waking from sleep are typical; hanging the hand out of bed;
massaging or shaking it may bring relief. Symptoms may be brought on by certain activities,
eg. driving, reading, typing, knitting. If the nerve is severely squeezed the hand or fingers may
feel continuously numb and weak. Objects may be dropped and tasks requiring fine finger
movements may be difficult.
what happens if it is not treated?
If CTS is untreated the pressure on the median nerve can result in damage to the nerve.
Numbness of the thumb and fingers and weakness of the thumb may be permanent. In
advanced CTS the muscles at the base of the thumb may shrink. In long-standing CTS
symptoms may not improve even if CTS is treated. It can however eventually get better even
without treatment, so a decision to have an operation should be taken slowly.
what tests can be done?
The diagnosis of carpal tunnel syndrome can usually be made from the symptoms and by the
findings of a medical examination. Nerve conduction tests can be used to confirm the
diagnosis if there is doubt, or unusual or atypical symptoms- small electrodes are placed
above the wrist to stimulate the median nerve; in CTS there is a time delay before the impulse
arrives in the muscles of the thumb.
Is there any treatment other than an operation?
Wearing a wrist splint at night helps some patients. Non-steroidal anti-inflammatory tablets
(eg. Ibuprofen) may help; water tablets (diuretics) are occasionally prescribed if fluid retention
D J Bracey April 2011
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is a problem. Treatment of any underlying diseases helps. Steroid injection into the carpal
tunnel is sometimes useful but the effects are sometimes short-lived.
what about an operation?
Failure of non-operative treatment is an indication for surgical release to relieve pressure on
the median nerve. If there are severe signs and symptoms of CTS then decompression may
be recommended without a trial of non-operative treatment. Surgery is usually carried out
under local anaesthetic as a day case. Surgery leaves a 2” scar in the palm of the hand.
what is it like having an operation for CTS?
Carpal tunnel release is a very effective operation. It is done under a local anaesthetic as a
daycase. You should not have anything to eat or drink for about 4 hours before the operation.
The palm of the hand is numbed up with local anaesthetic. The local can last as long as 6 hrs
so there is no risk of it wearing off during the procedure, which only takes about 10 mins. The
local sometimes numbs the fingers as well. The ligament on the front of the wrist is divided to
relieve pressure on the nerve.
what happens after the operation?
After the operation the hand is put in a crepe bandage. It helps to use the fingers right from
the start by fully straightening and bending them to disperse any bruising. You will be given a
sling but it is best to take the arm out of this regularly to stop the elbow and shoulder from
getting stiff. You will leave hospital shortly after the operation and need someone to take you
home. You will be given tablets, which should be taken as soon as the local anaesthetic starts
wearing off. It is far easier to keep the pain at bay than it is to relieve it if it is allowed to build
up. For the first 24hrs it helps to keep the hand elevated e.g. lying down with the hand raised
up on a pile of pillows.
how long does it take to recover?
The first clinic visit is usually 2 weeks after the operation when the dressings are removed and
3 or 4 skin sutures are taken out. A bandage may still be required and the hand and wrist
must be used only cautiously. The hand feels very weak. There must be no lifting or carrying
with the operated hand for at least 4 weeks after the operation. The hand finally returns to
normal when the ligament, which has been divided at the operation, reforms. This takes 4 - 6
weeks. For the first 4 weeks the hand and wrist must be protected from too much use,
particularly bending it forward, but with plenty of movement of the fingers to prevent any
stiffness. Once 3 or 4 weeks have passed following the operation the hand and wrist can start
to be used more normally. It will take a few months for the scar in the palm of the hand to
soften up.
what are the results of surgery?
Carpal tunnel decompression is usually successful; the hand eventually can return completely
to normal. In some individuals with severe long standing compression of the nerve, the return
of feeling and the recovery of weakness may take a long time and in some may never fully
recover.
can there be complications?
Fortunately these are rare. The scar can be tender. Infection of the wound is very unusual but
will respond to antibiotics. Sometimes some of the original symptoms may persist or may
return years later. Bruising and stiffness in the hand may occasionally need to be treated by
physiotherapy. Very rarely there can be damage to the nerve itself. You can see that although
this is a quick day-case procedure the recovery can in fact be rather slow, but the long term
results are usually very good.
D J Bracey April 2011