Carpal tunnel syndrome

Carpal tunnel syndrome is a disorder of the hand and wrist. It occurs when a nerve that runs through the wrist is squeezed or compressed, causing symptoms such as numbness, tingling, pain, and weakness of the hand.

Initial treatment aims to reduce and manage symptoms without surgery but if this is unsuccessful, a surgical procedure called carpal tunnel release may be recommended.

Signs and symptoms

The onset of carpal tunnel syndrome symptoms is usually gradual and can involve either one or both hands. The most common symptoms are numbness and tingling of the hand and fingers. Other symptoms may include:

• Burning, prickly, pin-like sensations in the hand and fingers
• Hand stiffness – particularly in the morning
• A feeling of swelling in the fingers – even though they may not be visibly swollen
• Weakened grip
• Pain in the hand and fingers. The pain may be intermittent or constant, worsen at night, worsen with increased use of the hand, and run up to the forearm or shoulder.

Causes

The carpal tunnel is a narrow passageway in the wrist that is surrounded by bones and ligaments. Running through the carpal tunnel are tendons that move the fingers and the median nerve, which is responsible for both sensation and movement in the hand, thumb, and fingers (excluding the little finger).

When the tissues in the carpal tunnel become swollen, the median nerve becomes compressed or “entrapped”.

Factors that increase the likelihood of developing carpal tunnel syndrome include:

• Certain conditions such as rheumatoid arthritis, diabetes, underactive thyroid and obesity
• A wrist injury such as a fracture or dislocation
• Pregnancy and menopause (fluid retention may increase pressure within the carpal tunnel)
• A family history of the condition.

The risk of developing carpal tunnel syndrome can be increased by activities or occupations that involve prolonged and highly repetitious movements of the wrist, especially when a forceful grip is required. Currently, there is no conclusive evidence to link keyboard and computer work with the development of carpal tunnel syndrome.

In the majority of cases the cause will be unknown.

Diagnosis

Doctors can normally diagnose carpal tunnel syndrome based on a discussion about the nature and circumstances associated with the symptoms, a physical examination and nerve conduction tests.

These tests measure how quickly nerves can transmit electrical impulses. Carpal tunnel syndrome may be indicated if impulses along the median nerve are slowed in the carpal tunnel.

Ultrasound or MRI scans may be recommended in some cases to confirm compression of the median nerve. MRI scans, x-rays and blood tests may be performed to rule out other possible causes for the symptoms, such as arthritis or a fracture.

Treatment

Treatment will depend on the nature and severity of the symptoms. Initial treatment will aim to reduce and manage symptoms without surgery.

Non-surgical treatment:

• Taking frequent breaks to rest the hands
• Applying a cold pack to reduce swelling
• Wearing a splint to support the wrist and prevent it moving into a position that further increases compression of the median nerve.
• Modifying how you do certain tasks or activities, or avoiding them altogether
• Non-steroidal anti-inflammatory drugs (NSAIDs) and/or corticosteroids (eg: cortisone injections)
• Physiotherapy.

If non-surgical treatment is unsuccessful, surgery may be recommended.

Surgical treatment:

The surgery is commonly referred to as a carpal tunnel release. It involves locating and cutting (releasing) ligaments around the carpal tunnel, relieving pressure on the median nerve.

The procedure may be done endoscopically (where instruments are passed into the wrist through small incisions) or using the open technique (where a larger incision is made to enable access to the surgical area).

Both surgeries are normally performed on a day-stay basis and can usually be carried out using a local anaesthetic. Endoscopic carpal tunnel release usually has a quicker recovery time, produces less post-operative pain and causes less scaring than open release surgery. However, this type of surgery is not suitable for all people.

Post-operative recovery

Symptom improvement after carpal tunnel release surgery is usually quick and complications are unusual. Most people who undergo carpal tunnel release surgery will have complete relief of symptoms although full recovery may take up to a year.

References

Accident Compensation Corporation (2010). Knowing about your carpal tunnel syndrome (Leaflet PDF). Wellington: Accident Compensation Corporation New Zealand. https://www.acc.co.nz/assets/im-injured/ea6eb431e1/acc2177-know-carpal-tunnel.pdf
Mayo Clinic (2017). Carpel tunnel syndrome (Web Page). Rochester, MN: Mayo Foundation for Medical Education and Research. https://www.mayoclinic.org/diseases-conditions/carpal-tunnel-syndrome/symptoms-causes/syc-20355603 [Accessed: 24/01/20]
OrthoInfo (2016). Carpal tunnel syndrome (Web Page). Rosemont, IL: American Academy of Orthopaedic Surgeons. https://orthoinfo.aaos.org/en/diseases--conditions/carpal-tunnel-syndrome/ [Accessed: 24/01/20]
O’Toole, M.T. (Ed.) (2017). Carpal tunnel syndrome. Mosby’s Dictionary of Medicine, Nursing & Health Professions (10th ed.). St Louis, MI: Elsevier.

Last reviewed – January 2020

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