Carpal tunnel syndrome (CTS) is a disorder that affects the hand and wrist. It occurs when the median nerve hich runs through the wrist is compressed, causing such symptoms as changes in sensation, pain, and restricted use of the hand.
Carpal tunnel syndrome most commonly occurs in women, with those aged between 30 and 60 years having the highest rates of the condition. Initial treatment aims to reduce and manage symptoms without surgery but if this is unsuccessful, surgery may be recommended.
Signs and symptoms
The onset of CTS symptoms is usually gradual and can affect 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
- Wasting of the muscles in the hand can occur in long-term (chronic) cases
- 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; radiate from the hand to the forearm or shoulder.
The carpal tunnel is a narrow passageway in the wrist that is surrounded by bones and ligaments. Through it run tendons that move the fingers and the median nerve, which is responsible for both sensation and movement in the hand, thumb, index finger, middle finger and ring finger.
Any condition that causes swelling of the membranes or other contents of the carpal tunnel can lead to CTS. When the tissues of the carpal tunnel become swollen, pressure inside the carpal tunnel is increased. This causes the median nerve to be compressed, known as nerve entrapment.
Factors that increase the likelohood of developing CTS include:
- Female gender
- Being overweight or obese
- Certain medical conditions such as rheumatoid arthritis, diabetes and hypothyroidism
- A wrist injury such as a fracture
- A family history of the condition.
The risk of developing CTS can be increased by activities or occupations that involve prolonged and highly repetitious flexion or extension of the wrist, especially when a forceful grip is required. Hand-transmitted vibration is also thought to increase risk. However there is no conclusive evidence to link keyboard and computer work with the development of CTS. In the majority of cases the cause will be unknown (idiopathic).
If carpal tunnel syndrome is suspected, a doctor should be consulted so that an accurate diagnosis can be made and appropriate treatment recommended.
The doctor will take a full medical history, discussing symptoms and the activities/situations that worsen them. The affected hand will be examined and an assessment of the ways in which the hand is used will be made. The doctor may also perform several simple tests on the affected hand to see if the symptoms can be induced.
If the initial examination clearly indicates the presence of CTS then further tests may not be required. However, if there is doubt about the diagnosis then nerve conduction tests may be required. These tests measure how quickly nerves can transmit electrical impulses. CTS may be indicated if impulses along the median nerve are slowed in the carpal tunnel. This is a specialised test and a referral to a specialist will be required in order for this test to be performed.
Ultrasound or MRI scans may be recommended in some cases to confirm compression of the median nerve. Blood tests may also be performed to rule out other possible causes for the symptoms.
Treatment will depend on the nature and severity of the symptoms. Initial treatment will aim to reduce and manage symptoms without surgery.
- Wearing a splint to support the wrist and prevent it moving into a position that further increases compression of the median nerve.
- Modifying techniques and practices
- Avoiding activities that worsen symptoms
- Anti-inflammatory medications and/or cortisone injections
If non-surgical treatment is unsuccessful, surgery may be recommended.
Surgery is normally performed on a day stay basis and can usually be carried out using a local anaesthetic and/or a nerve block. The surgery is commonly referred to as a carpal tunnel release.
There are two main techniques used for carpal tunnel release. The decision as to which is used will be decided largely by the surgeon.
Open Release Surgery
An incision is made in the wrist and palm and the surgeon locates the flexor retinaculum (a strong band of tissue within the carpal tunnel that wraps the median nerve and the tendons that move the fingers). The flexor retinaculum is cut and released, thereby relieving the pressure on the median nerve. The skin is stitched back together and a dressing is applied.
This technique uses a narrow telescope called an arthroscope to view the structures of the carpal tunnel from the inside. Usually, two small incisions are made – one in the wrist and one in the palm. The arthroscope is passed through one incision and the surgical instruments through the other. The surgeon is able to see the structures of the carpal tunnel on a television monitor whilst using the surgical instruments to release the flexor retinaculum. The incisions are closed with either stitches or small paper tapes (steristrips) and a dressing is applied.
Endoscopic carpal tunnel release usually has a quicker recovery time, produces less postoperative pain and causes less scaring than open release surgery. However, this type of surgery is not suitable for all people.
Post Operative Recovery
Recovery from carpal tunnel release surgery is usually quick and complications are unusual. Approximately 95% of those who undergo carpal tunnel release surgery will have complete relief of symptoms.
It is important to follow post operative recovery and activity guidelines. Some surgeons will recommend the use of a splint. This helps to restrict movement and promote healing. Gentle hand exercises or physiotherapy may also be recommended.
If CTS has been present long-term (chronic), it may take longer for symptoms to disappear and normal function to return to the hand. Also, some muscle wasting may remain even though a complete relief of CTS symptoms has been achieved.
Although rare, CTS can recur, even after carpal tunnel release surgery. A doctor should be consulted if recurrence of CTS is suspected.
Accident Compensation Corporation. Carpal Tunnel Syndrome Fact Sheet (2009).
Anderson, K.N., Anderson, L.E. & Glanze, W.D. (eds.) (2006) Mosby’s medical, nursing, & allied health dictionary (6th ed.) St. Louis: Mosby-Year Book, Inc.
Carson-DeWitt, R (2006) Carpal Tunnel Syndrome. The Gale Encyclopaedia of Medicine. Third Edition. Jacqueline L. Longe, Editor. Farmington Mills MI. Thompson Gale.
Dr David Beaumont, Occupational Medicine Specialist, www.fitforwork.co.nz
Last reviewed – 19 April 2013