Carpal Tunnel Syndrome

Mr Mike Hayton
FRCS(Trauma and Orth) FFSEM (UK)
Consultant Orthopaedic Hand Surgeon

Other common names

None

Who does it affect?

It can occur in any patient but is more common in females over the age of 40 years.

Why does it occur?

In the majority of patients, the cause is still unknown. However there are a number of medical conditions that predispose patients to Carpal Tunnel syndrome. These include pregnancy, thyroid disease, rheumatoid arthritis and wrist injuries. It is important to note that if you have one of these conditions it does not mean that you will definitely develop carpal tunnel syndrome, hwever may just be slightly more at risk.

Carpal tunnel syndrome occurs when the median nerve is compressed at the level of the wrist. The nerve and tendons that bend the fingers pass from the forearm into the hand through a narrow tunnel called the carpal tunnel. When there is a build up of pressure in this tunnel the nerve becomes squashed and causes symptoms of carpal tunnel syndrome.

Symptoms

Pins and needles in the thumb, index and middle fingers. This commonly occurs at night and the patient is often awakened from sleep and has to shake their hands to gain relief from these symptoms. Occasionally in severe cases, the muscles on the front of the palm next to the thumb can waste, causing hollowing. In such severe cases the thumb may become weak or clumsy.

Clinical Examination

Modified Phalen's test - Direct pressure over the carpal tunnel especially whilst bending the wrist forward, may reproduce the pins and needles in the thumb, index and middle fingers.

Tinel's test - Tapping the nerve in the carpal tunnel may cause tingling in these fingers.

Investigations

Nerve conduction studies are used to record the speed of the nerve across the wrist joint. This can be compared to the other hand, or in cases where both hands are affected, compared to normal population data. The test takes about 20 minutes and is slightly uncomfortable.

However if a patient has classical symptoms and physical examination of carpal tunnel syndrome, I do not routinely arrange these studies.

Non-operative treatment

Simple painkillers and resting splints can offer help. Occasionally a steroid injection into the carpal tunnel will improve symptoms. However the majority of patients who have troublesome symptoms have surgery. The last trimester of pregnancy is notorious for causing carpal tunnel syndrome, in such cases a splint of steroid injection can help. However on the birth of the baby the symptoms usually resolve over the coming months.

Operative treatment

Most patients who have troublesome carpal tunnel syndrome have surgery. The surgery is a day case procedure usually under local anaesthetic and takes about 10 minutes. A tourniquet is used; which is like a blood pressure cuff around the upper arm that prevents blood from obscuring the surgeons view. It is quite tight, but well tolerated for up to 20 minutes.

The surgery can be performed open (through a 4cm incision) or endoscopic
(Keyhole, through one or two 1cm incisions). The results are the same for both techniques, however I prefer to perform the surgery through the open technique.

Open technique

Local anaesthetic is infiltrated under the skin in line with the incision. Once numb, the skin is incised and then the underlying fat is retracted.

Care is taken not to injure sensory nerves to the palm. At the base of the wound is a thick band of tissue called the transverse carpal ligament. This structure needs to be released to allow the contents of the carpal tunnel to be decompressed.

Having released this ligament the contents of the carpal tunnel are inspected to ensure adequate release and no other conditions are present.
The skin is sutured with fine sutures and a bulky dressing is applied.

Post-operative rehabilitation

The patient is fit to go home soon after the operation. The anaesthetic will wear off after approximately 6 hours. Simple analgesia usually controls the pain and should be started before the anaesthetic has worn off. The hand should be elevated as much as possible for the first 5 days to prevent the hand and fingers swelling. Gently bend and straighten the fingers from day 1. My preference is to remove the dressing at 2 days. The wound is cleaned and redressed with a simple dressing. Avoid forced gripping or lifting heavy objects for 2-3 weeks. The sutures are removed at about 10 days. You should notice an improvement in symptoms within a week but the final result may be realised at about 3 months.

Click here to download a pdf on post operative instructions

Return to activities of daily living

It is my advice to keep the wound dry until the stitches are out at 10 days.

Return to driving : The hand needs to have full control of the steering wheel and left hand the gear stick. It is probable advisable to delay return to driving for at least 7 days or even once the sutures are removed.

Return to work : Everyone has different work environments. Return to heavy manual labour should be prevented for approximately 4-6 weeks. Early return to heavy work may cause the tendons and nerve to scar into the released ligament. Please ask your surgeon for advice on this.

Complications

Overall, greater than 95% are happy with the result. However complications can occur.
There are complications specific to Carpal Tunnel Release and also general complications associated with hand surgery.

General complications:

 - Infection (Less than 1%),
 - Neuroma (Less than 1% coiled painful nerve bundle)
 - Numbness

Reflex Sympathetic Dystrophy - RSD (2% bad reaction to surgery with painful stiff hands - this can occur with any hand surgery from a minor procedure to a complex reconstruction.)

Specific complications:

Failure to completely resolve the symptoms (approximately 5% - this may be due to chronic scarring of the nerve due to long duration of pre-operative pressure, symptoms suggesting this include muscle wasting and severe numbness.
Pillar pain (less than 2%, a poorly understood complication with pain on the front of the wrist),
Numbness in the palm (less than 1%, a small branch of the nerve passes across the skin incision, care must be taken too avoid injury to this).

New Carpal Tunnel Web Site

Mike Hayton has a new web site specifically dedicated for carpal tunnel syndrome.

Click here for the direct link.