Carpal Tunnel Syndrome

What is carpal tunnel syndrome?

Carpal tunnel syndrome is a condition that affects the hands. It commonly occurs in those between the ages of 45 – 60 years of age or those over 80. It can however affect individuals at almost any age.

The carpal tunnel is an anatomical structure in the base of the hand where it connects with the wrist. The floor of the tunnel is formed by an arch of bone and the roof by a ligament (transverse carpal ligament) creating a true tunnel. Through this tunnel travels nine of the tendons that bend the fingers and thumb and the median nerve.

Carpal tunnel syndrome occurs when the median nerve becomes compressed (squashed) within the carpal tunnel.

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What is the function of the median nerve?

The median nerve is an important peripheral nerve that passes through the carpal tunnel in the hand. There are two functions to this nerve.

1. To supply sensation to the palm side of the thumb, index, middle and half of the ring finger.

2. To supply some of the small muscles within your hand, particularly the thenar muscles. This group of muscles at the base of the thumb are responsible for the ability to oppose the thumb onto the other digits.

What causes carpal tunnel syndrome?

In most cases there is no specific cause. We do however know that there is a maximum volume within the carpal tunnel and it cannot expand. If any structure gets bigger or takes up more room in the tunnel then the median nerve will be put under pressure causing symptoms.

Conditions that can increase pressure within the tunnel include;

Obesity (increased fat within the tunnel)
Pregnancy (increase fluid within the tunnel)
Tenosynovitis (inflammation of tendon linings). This can occur on its own or part of another condition such as rheumatoid arthritis.
Trauma or injury.
Arthritis (loss of volume within the tunnel due to inflammation and new bone formation).
There are also associations with other conditions for example diabetes and thyroid disease.

What are the symptoms of carpal tunnel syndrome?

The symptoms of carpal tunnel syndrome can vary between individuals however symptoms can be broken down into mild or severe. Please note it is possible to skip early stages and present with late changes initially.

Mild: In this stage symptoms often include;

Intermittent tingling, pins and needles, burning or a loss of feeling classically affecting the thumb, index, middle and half of the ring finger on the palm side of the hand.
Symptoms often occur at night and can disturb sleep. Patients waking in the night often describe having to shake their hand or hang their hand over the side of the bed to to try and relieve their symptoms.
Symptoms can also occur during the day particularly with certain activities such as driving, reading or repetitive manual tasks.
In the early stages the sensation to the hand is well preserved despite the occasional loss of feeling. One may wake with loss of feeling for example, but this will quickly return to normal once the hand is moved.
In the early stages the thenar muscles (those at the base of the thumb) are still working. They have a normal amount of muscle and strength is preserved.

Severe: In this stage symptoms often include;

All of the above but the symptoms may become more constant to the point where they are always present.
The fingers and thumb may have a loss of feeling all or most of the time and as a result one may have difficulty with fine tasks for example doing up shirt buttons, being able to correctly identify objects in one’s pocket or threading a needle.
As a result of the longstanding nerve compression the thenar muscles (those at the base of the thumb) which are supplied by the median nerve may begin to waste away. You may notice a loss of muscle size at the base of the thumb and a reduced ability to squeeze the thumb against the other fingers.

Diagnosis and investigations

The diagnosis of carpal tunnel syndrome is usually made simply by asking the right questions and examining the patient correctly.

Occasionally, investigations such as nerve conduction or electromyography studies are required.

These are performed at a second visit to the clinic and are simple and reliable tests which will help determine the correct diagnosis and treatment for you.

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Treatment of carpal tunnel syndrome

In some cases of mild carpal tunnel syndrome, for example where the condition has been present for less than 3 months or has an obvious reversible cause (e.g. pregnancy), the symptoms may resolve spontaneously by themselves.

If this does not occur in mild cases, non-surgical measures such as wrists splints and/or steroid injections can be considered.

Wrist splints and steroid injections

Most cases of carpal tunnel syndrome are mild or have been present for a short period of time (less than 3 months). In this situation we can provide you with simple wrist splints to wear on the affected hands at night for a trial period of 3 months or administer a steroid injection.

How do wrist splints work?

When we bend our wrists, we know that the pressure is increased within the carpal tunnel and therefore causes pressure on the median nerve. At night most of us sleep with bent elbows and curled wrists hence why nocturnal symptoms are so common.

Splints are designed to keep the wrists straight at night thereby preventing this problem.

There are very few side effects from splint use but it is important to ensure the right type is used and that they are fitted correctly. The most common problem with wrist splints is that they cause discomfort.

In mild cases of carpal tunnel syndrome wearing night time wrist splints may cure the problem.

What are steroid injections?

Steroids are an anti-inflammatory medication which are used for a variety of medical conditions. In carpal tunnel syndrome a specific type of steroid is injected using a small needle directly into the carpal tunnel at the base of the hand where it meets the wrist. Local anaesthetic is used to reduce discomfort.

The steroid helps to decrease inflammation and therefore increase the space in the tunnel taking pressure off the nerve. This then allows the nerve to recover and the symptoms to improve.

Symptom improvement may take some weeks but in mild cases of short duration steroids can cure the problem with a single injection.

Small doses of locally administered steroids given under supervision are considered safe during pregnancy and breastfeeding.

There are some specific risks to be aware of.

Loss of pigment. The steroid can cause a loss of normal skin pigment (change in skin colour) at the injection site which may be temporary or permanent.
Fat atrophy. The injection can lead to some loss of fat under the skin which may alter the skin's contour.
Infection. There is a very small risk (around 1%) of introducing infection into the soft tissues of the carpal tunnel. This might lead to pain, redness and swelling around the injection site. Mild infections may need antibiotics but more severe infections which are very rare may need admission to hospital for treatment.
Nerve injury. There is an extremely small risk of injury to the median nerve. If the needle or steroid is injected directly into the nerve in error rather than into the space within the tunnel it could cause temporary or permanent damage leading to a loss of sensation and/ or function.
Tendon rupture. This is again a very rare complication which could occur if steroid is injected within a tendon. This would require surgical correction.
Erratic diabetic control. As with any other steroid medication some patients with diabetes, particularly those on insulin may find that their blood sugar levels fluctuate following the steroid injection. Close blood sugar monitoring is therefore advised following the procedure.

Surgery

Surgery for carpal tunnel syndrome is indicated for;

Those who have failed conservative treatment with splints or injections.
Those with severe carpal tunnel syndrome where there are signs of muscle wasting at the base of the thumb or where there is any permanent loss of sensation.

Surgery can be performed in two ways.

1. Open carpal tunnel release.

2. Endoscopic carpal tunnel decompression.

Open carpal tunnel release

This is the gold standard treatment for carpal tunnel syndrome that has failed first line treatments (including night splints and steroid injections) or for severe cases.

It is performed as a local anaesthetic procedure and as a day case (this means you do not need to stay in hospital overnight).

The actual operation takes around 10 minutes to perform but the whole process takes approximately an hour and includes the safety checks, administration of anaesthetic, actual surgery and dressing application.

You should not feel any pain during the procedure but you may be aware of some light touch or pressure, the surgeon will communicate with you throughout the surgery.

You are welcome to use headphones to listen to music to help distract you if you would like (please remember to bring an audio device and headphones with you).

The procedure: A small incision roughly 2.5cm in length is made in the palm and the ligament that forms the roof of the carpal tunnel is released. This increases the volume within the tunnel taking pressure off the nerve. The skin is then stitched with dissolvable sutures and dressings applied.

Following the surgery, you will be given a sling, encouraged to elevate the hand to prevent swelling and instructed to move the fingers immediately. The hand may be more numb than before the surgery due to the local anaesthetic which should wear off within 24 hours. Most patients find that their night symptoms improve from day 1 post-surgery.

Endoscopic carpal tunnel release

The procedure is identical to the open carpal tunnel release as described above but involves the use of a device that combines a small camera and cutting mechanism.

Through a small incision (less than 1cm) the device (endoscope) is inserted into the carpal tunnel under local anaesthetic. The roof of the tunnel is then released from within.

The main advantage of endoscopic carpal tunnel surgery over open surgery is a faster recovery and return to function.

After six months however, there is no difference in outcome between these procedures.

Risks

Infection: This is rare (less than 1%). If infection occurs it may cause redness, tenderness and swelling around the wound. Treatment is likely to require antibiotics and very occasionally surgery.
Stiffness: This can be minimised by getting the wrist and fingers moving as quickly as possible after the operation. Advice on specific exercises will be given post- operatively before you go home.
Scar sensitivity: The scar may be sensitive for around 3 months and occasionally longer although the sensitivity is rarely permanent.
Loss of grip strength: By dividing the roof of the carpal tunnel we alter the biomechanics and as a result grip strength can be reduced for up to 3 months. With time this should return to normal.
Nerve injury: This is very rare with an experienced surgeon. If it does occur, further surgery may be required and the injury may lead to permanent loss of sensation and/or power of the muscles at the base of the thumb.
Failure to improve: In the majority of cases, carpal tunnel surgery is extremely successful but for those individuals who have severe compression, the level of improvement may be suboptimal. Once a nerve has been severely compressed for long enough the nerve fibres can degenerate leading to permanent loss of function. Surgery in these situations can prevent the problem getting worse and may improve some symptoms (for example tingling) but is unlikely to reverse the poor sensation or strength. It is for this reason that we do not recommend delaying surgery when we feel it is indicated.
Complex regional pain syndrome: Fortunately this is very rare (0.2%) but can occur following any surgery to the limbs. Symptoms include swelling of the affected area, skin discolouration, abnormal sensation, pain, and abnormal hair and nail growth. It is not fully understood why it occurs but requires urgent diagnosis and treatment with painkillers and hand physiotherapy. Patients can make a full recovery but some patients will have permanent loss of function.
Recurrence: This is a rare situation where, after successful carpal tunnel release, symptoms may return some years later (typically 10 years or more). Patients are treated as if they had a new diagnosis of carpal tunnel syndrome and repeat surgery is often successful.

Recovery timeline

1 week post operation

You may experience mild discomfort.
Try to keep the hand elevated and dry.
Use the hand for essential tasks only.
Avoid using the hand to lift or grip.
Undertake the post- operative exercises given to you on the day of surgery.

2 weeks post operation

The discomfort should now be minimal.
The dressings should have been removed and the stitches should be well on their way to dropping off/dissolving.
The hand can be used for more activities of daily living such as eating and drinking, showering and tooth brushing.
If the wound is dry it can now be submerged under water.
Finger movements can now be increased. Fingers should be able to fully straighten and grip.
Non- manual based workers should be able to return to work at this stage but can return earlier if able.

6 weeks post operation

There should be significant improvement in strength and function.
The wound should be healing well.
The scar should not be painful but may be uncomfortable when pressed hard and may feel thickened.
There should be a full range of movement in the hand and wrist and you should be able to grip objects with only minor discomfort.
You can use the hand for heavier tasks including lifting, pushing and gripping.
Manual workers should be able to return to work by this stage but can return earlier if able.

3 months post operation

You should be able to do all normal activities without restriction or pain.
There should be only minimal scar sensitivity.

what is carpal tunnel

what is the function of the median

whatcauses carpal,

what ae the symptoms

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Devon Hand Surgery aims to give you an early diagnosis, rapid treatment (which can often be non-surgical) and perform any necessary surgery when required. We will also supervise your rehabilitation to ensure you have the best chance of restoring function, getting back to work and improving your quality of life.

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