Carpal Tunnel Syndrome

What is carpal tunnel syndrome?

Carpal tunnel syndrome (CTS) is the commonest form of nerve entrapment and occurs when the median nerve is compressed at the wrist in the carpal tunnel. It needs timely treatment to prevent avoidable, irreversible and disabling loss of feeling and power in the hand.

The median nerve and finger bending tendons pass through a tunnel across the front of the wrist. The tunnel is made of wrist bones covering the floor and walls and the roof is made of a strong fibrous ligament. Normally the pressure in the canal is very low. The increase in pressure in the tunnel could compromise the blood supply to the nerve and cause pain/numbness and tingling.



What are the symptoms of CTS?

This is usually felt as pain, tingling or numbness in part of the hand, usually the thumb, index and middle fingers. Sometimes the symptoms are felt in the whole hand. The intensity of pain, tingling and numbness are often quite variable in severity. The symptoms are typically worse at night and with certain daytime activities such as driving, cycling and reading. Shaking the hand may relieve the symptoms. One or both hands can be affected.


Why does it occur?

In most cases, it's not known what causes the median nerve to become compressed, although the following increase the risk of developing CTS.

  1. Family history
  2. Health conditions - diabetes, an underactive thyroid gland or rheumatoid arthritis and obesity
  3. Pregnancy - Many cases resolve after the baby is born.
  4. Injuries to the wrist
  5. Certain activities
    • Playing a musical instrument
    • Assembly packing
    • Work that involves manual labour
    • Work with vibrating tools, such as chainsaws

6. Other

    • Cysts, growths or swellings in the carpal tunnel
    • some drugs used to treat breast cancer – such as exemestane (Aromasin)
    • Menopause.


What happens if nothing is done?

As carpal tunnel syndrome progresses, you may feel you are losing coordinated movement of your fingers. You may notice weakness in your fingers that makes it hard to do daily tasks, such as buttoning buttons. The symptoms of pain/numbness will increase and most people are particularly troubled by night waking often in the early hours of the morning. If left for too long permanent numbness and muscle weakness could reduce the hand function considerably.



How is it diagnosed?

Carpal tunnel syndrome is diagnosed by a hand specialist based on an evaluation of your symptoms, physical examination and if needed an electrophysiologic test. The surgeon will also examine the patient‘s neck as this can give numbness and tingling in the hands similar to CTS.




  • Nerve conduction study/Neurophysiology/EMG - This is performed at a later date by a specialist (Neurophysiologist). Mild electric shocks are sent up and down the arm and the strength and speed of their conduction is measured. The test measures the electrical signals passing through the median nerve and how the muscles that are supplied by the nerve are being affected. It can show if the nerve is compressed. Like all tests it is not completely reliable so it can be normal although the patient has CTS and it can be abnormal when the patient does not have CTS. Your Hand specialist will interpret the results in the light of the previous description of symptoms and examination and advise you accordingly.
  • Rarely X-rays, Ultrasound/MRI scans, blood tests are performed to rule out other causes of CTS




What are the non-operative treatments?

  1. Wrist splint is often the first step in treatment. A splint can be particularly helpful for people whose symptoms are bothering them at night. Wearing a splint during the night can keep the wrist from bending or being extended while you sleep. That often relieves the nerve pressure and eliminates nighttime discomfort. Wearing a splint during the day also can be useful if symptoms persist during waking hours. Some people don't like wearing a splint during the day, though, because moving the wrist naturally may be difficult.
  2. Corticosteroid injection into the carpal tunnel may help reduce symptoms. Corticosteroids lower inflammation and swelling within the carpal tunnel, which can relieve pressure on the median nerve.
    • Benefit may be temporary.
    • Rarely more than two injections are beneficial
    • If the symptoms are marked and established, surgery may be appropriate
    • Where the clinical picture is unclear a positive response to an injection helps confirm the diagnosis.


What does the operation involve?

The operation is called a carpal tunnel release (CTR) or decompression (CTD). The operation is usually performed as a day case surgery (means, you won't have to stay in hospital overnight.) under local anaesthetic.

On the day of surgery

  1. A local anaesthetic is used to numb your hand and wrist, but you'll remain awake throughout the operation. General anaesthetic is rarely advised (patients with needle phobia)
  2. A tourniquet, like a blood pressure cuff, is placed around the top of the arm. It is inflated (tightened) during the operation to reduce bleeding, which makes the operation easier and safer. It can be a little uncomfortable, but is almost always well tolerated by our patients. Before that the arm is painted with an antiseptic to help minimise the risk of infection.
  3. The surgeon makes a cut over the front of the wrist, and the roof over the tunnel is released, so that the nerve has more space in its tunnel. The skin is then stitched up usually with absorbable stitches. A supportive dressing is applied and the patient's arm(s) elevated.

The total time in hospital is usually 1-2 hours.

For most hand conditions surgeons avoid operating on both hands at once as it can be significantly disabling. The decision to release both sides at once, is a decision between the patient and the surgeon.



What happens after surgery?

  1. The care of the hand in the post-operative period is very important in helping to achieve a good result.
  2. The local anesthetic wears off 4-10 hrs after surgery, patients are encouraged to start taking painkillers before the pain starts i.e. on return home and for at least 24 hours from there. This way most of our patients report little or any pain.
  3. Initially the aims are comfort and elevation of the hand in a bandage for a couple of days, and you may need to wear a sling.
  4. Gently exercise your fingers, shoulder and elbow to help prevent stiffness. You may be able to start these gentle exercises on the day of your operation.
  5. After having surgery for CTS, you can use your hand to do light activities that don’t cause excessive pain or discomfort. Try to avoid using your hand for more demanding activities until it’s completely recovered, which may take several weeks.
  6. The bandage can be removed after 2-7 days, leaving a sticky dressing beneath. The patient or GP practice nurse can do this. The patient is reviewed in clinic around 2 weeks following the operation for wound check and removal of sutures.
  7. The wound should be massaged (typically after 2 weeks) using moisturising cream by the patient 3 times a day for 3 months once the wound is well healed. This reduces the scar sensitivity and scar related complications (tenderness, helps scar to mature). Hand therapy for scar management will be needed in few patients.
  8. Most patients can drive after the wound has healed (usually 2 weeks). Most patients return to work in 2-3 weeks, but this varies with occupation; heavy manual work usually takes about 6 weeks. Patients should avoid pressing heavily on the scar for 3 months following the operation as this will be quite painful.



Are there any risks?

  1. Any operation can have unforeseen consequences and leave a patient worse than before surgery. For CTD the risks are small but include:
  2. The scar may be tender in about 20% of patients. This usually improves with scar massage, over 3 months.
  3. Aching, especially on gripping. This occurs in about 4% of patients and also improves with time. Grip strength can also take some months to return to normal.
  4. Stiffness may occur in particular in the fingers. This is usually short-term and only infrequently requires physiotherapy. But it is very important that it is resolved quickly to avoid permanent stiffness. This occurs rarely but can do associated with CRPS (see below).
  5. Numbness over the base of the thumb, caused by damage to a branch of the nerve, happens in less than 4% of patients. This rarely causes any functional problems.
  6. Wound infections occur in about 1% of cases. These usually quickly resolve with antibiotics.
  7. Chronic Regional Pain Syndrome "CRPS". This is a rare but serious complication, with no known cause or proven treatment. The nerves in the hand "over-react", causing swelling, pain, discolouration and stiffness, which very slowly improve.
  8. Injury to the main median nerve can occur extremely rarely, resulting in permanent numbness and weakness in the hand.
  9. Failure to fully separate the roof of the carpal tunnel during surgery, usually resulting in persistent CTS symptoms
  10. In rare cases, the return of CTS symptoms long after apparently successful surgery



What are the results of the operation?

The overall success rate of carpal tunnel open surgery is more than 95% with a complication rate of less than 3%. Most patients have very rapid or immediate relief of their pain. Symptoms of numbness or weakness may well never resolve particularly if there was continuous numbness or weakness prior to surgery (permanent damage to the nerve even before the surgery). Nonetheless most patients gain significant benefit in these symptoms, which may improve for up to 2 years from surgery.



Additional information for medical professionals/GP’s:

The prevalence of Carpal Tunnel Syndrome in the UK is 7–16%. A UK General Practice Research Database found that 88 men and 193 women present as new cases per 100,000 population. In secondary care 52996 procedures are undertaken annually. The surgical decompression rate is 43–74 per 100,000. The proportion of carpal tunnel release procedures undertaken as day cases varies between 96.69% and 99%.


Urgent referral for:

Red Flags


Onset of tingling/ numbness after injury

Nerve tumour, tumour, symptoms associated with any lump in the carpal tunnel area


Yellow Flags, urgent referral (<2/52)

Neurological diseases

Inflammatory joint disease (including gout and RA)

Peripheral limb ischaemia (thoracic outlet syndrome or Raynaud’s disease)

Cervical nerve root entrapment

Only one modality of conservative treatment should be used as failure on one conservative treatment is a predictor that others will also fail.


There is no convincing evidence to support the use of non-conventional conservative treatments e.g. Laser treatment and acupuncture.



Conservative treatment:

  1. Median or ulnar nerve immobilisation techniques:Wrist splints (wrist in neutral) at night for Carpal Tunnel Syndrome. To be used as an initial treatment and not to be over-relied on, due to limited effectiveness.
  2. A single steroid + local anaesthetic injection.
  3. Patients with a potential reversible cause (pregnancy, hypothyroidism) can be considered for conservative treatment.
  4. Patients with mild carpal tunnel syndrome should be improved in up to 6 weeks of such management.



To see a surgeon: ( or use carpal tunnel questionnaire – Appendix A)

  1. Moderate to severe or deteriorating symptoms.
  2. Daily symptoms, frequent night waking.
  3. Persistent symptoms causing functional impairment not responding to up to 12 weeks of evidence based 15 non-surgical treatments; this time to include any treatment received in primary care. Note there is a growing body of evidence emphasising the need to avoid inappropriate delay in referral.
  4. Patients with moderate or severe carpal tunnel should be considered for surgery.
  5. Where conservative management has failed and surgical treatment is considered.
  6. Surgical outcomes may be poorer after long periods of persistent symptoms.
  7. Patients who are not suitable for surgery or have decided not to have surgery should be offered an appropriate care package.


To be seen by a hand surgeon:

  1. Sudden severe symptoms
  2. Marked weakness with function deficit which may need reconstructive surgery such as tendon transfers
  3. CRPS 1 not resolving in a fortnight
  4. Nerve injury
  5. Recurrent or persistent tingling after decompression
  6. After surgery




Nerve Conduction Studies (NCS) done for


Equivocal clinical examination and history

Persistent or recurrent carpal tunnel syndrome

An unclear diagnosis suggesting peripheral neuropathy

Work related, medico legal issues




As a day case in an ambulatory or in-patient facility, unless clinical or social circumstances dictate otherwise. Under local or regional anaesthetic, although general anaesthetic may be needed occasionally.

Patients will normally need around 2 outpatient follow appointments or equivalent to identify

  1. A small minority of patients who will need hand therapy.
  2. And manage early - Sensitive scar, Nerve damage and CRPS

Recurrence rates after carpal tunnel decompression are between 0.3 and 12%.



Based on BOA guidelines, RCS guidelines, NICE CKS and AAOS

Appendix A:





Has pain in the wrist woken you at night?




Has tingling and numbness in your hand woken you during the night?




Has tingling and numbness in your hand been more pronounced first thing in the morning?




Do you have/perform any trick movements to make the tingling, numbness go from your hands?




Do you have tingling and numbness in your little finger at any time?




Has tingling and numbness presented when you were reading a newspaper, steering a car or knitting?




Do you have any neck pain?




Has the tingling and numbness in your hand been severe during pregnancy?


Subtract 1


Has wearing a splint on your wrist helped the tingling and numbness?





  • A score of <3 is unlikely to be indicative of Carpal Tunnel Syndrome
  • A score of 3-4 suggests Carpal Tunnel Syndrome is possible cause of symptoms
  • A score of 5 or more is strongly suggestive of Carpal Tunnel Syndrome