Carpal Tunnel Syndrome
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 a major nerve called the median nerve, which is responsible for both sensation and movement in the hand, thumb, index finger, middle finger and ring finger.
Carpal tunnel syndrome (CTS) is a common disorder that affects the hand and wrist. It occurs when the median nerve is compressed, causing changes in sensation, pain, and limiting the full use of the hand. It most commonly occurs in women, with women aged between 30 and 60 years having the highest rates of the condition. CTS can affect either one or both hands.
Signs and Symptoms
The most common symptoms of carpal syndrome 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:
- radiate from the hand to the forearm or shoulder
- be intermittent or constant
- worsen at night
- worsen with increased use of the hand.
Causes
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.
This is known as nerve entrapment. It is more common in obesity (BMI greater than 30), and pregnancy as well as certain medical conditions such as rheumatoid arthritis, diabetes, acromegaly and hypothyroidism. Those with a family history of CTS may have a greater predisposition to the condition.
It has previously been theorised that CTS was associated with occupations or activity that involves repetitive and / or forceful movements of the hand and wrist. However, more recent studies have found that the link between occupational tasks and the development of CTS to be uncertain with considerable controversy surrounding what if any link, CTS has with occupation. It has been suggested that the only factors conclusively linked to an increased risk of CTS are female gender and greater relative body weight, although the majority of cases are idiopathic (of unknown cause).
Diagnosis
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.
Blood tests and x-rays may also be performed to rule out other possible causes for the symptoms.
Treatment
Non Surgical Treatment:
- 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
- Use of an ergonomically designed wrist support for keyboard operators
- Frequent rest breaks
- Avoiding activities that worsen symptoms
- Anti-inflammatory medications and/or cortisone injections
- Physiotherapy
If non-surgical treatment is unsuccessful, surgery may be recommended.
Surgical Treatment:
Surgery is normally performed on a day stay basis and can usually be carried out using a local anaesthetic or a nerve block (injection of anaesthetics directly into the nerve). The surgery is commonly referred to as a carpal tunnel release.
There are two main techniques used for carpal tunnel release.
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.
Endoscopic Surgery
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. However this type of surgery is not suitable for all people. The decision as to which surgical technique is to be used for the carpal tunnel release will be decided by the surgeon prior to surgery.
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 the relief of symptoms and a return of normal function. Also, some muscle wasting may remain even though a complete relief of CTS symptoms has been achieved.
Recurrence
Although rare, CTS can recur, even after carpal tunnel release surgery. A doctor should be consulted if recurrence of CTS is suspected.
References
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.
Everybody (1999) Carpal Tunnel Syndrome. CMPMedica (NZ) Ltd. http://www.everybody.co.nz/page-5e26ba70-ec51-40be-a083-d5c2c9dfd8b1.aspx
Last Reviewed – 10/12/2009