Carpal Tunnel Syndrome

Carpal tunnel syndrome develops when anything reduces the space in the tunnel or increases the volume of its contents, raising the pressure on the median nerve. Often no single cause is found. Recognised associations include being female, increasing age, obesity, pregnancy, diabetes, an underactive thyroid, rheumatoid arthritis, and previous wrist injury. Work or activities involving forceful, repetitive or vibrating hand use may contribute in some people. Fluid retention, such as in pregnancy, can bring it on temporarily.

The typical symptoms are tingling, pins-and-needles and numbness in the thumb, index and middle fingers, and often part of the ring finger. A very characteristic feature is that symptoms are worst at night and can wake people from sleep, who then shake or dangle the hand to relieve them. Some people feel clumsy, drop things, or struggle with fine tasks such as buttons. In more advanced cases there can be constant numbness and wasting and weakness of the muscles at the base of the thumb.

The diagnosis is usually made from the pattern of symptoms and a clinical examination, and validated clinical assessment tools are reliable for this. Nerve conduction studies — tests that measure how well the median nerve is working — are used in some cases to confirm the diagnosis, judge severity, or where the picture is unclear or surgery is planned. An ultrasound scan can also be helpful. Together these establish the diagnosis and how severe the nerve compression is, which guides treatment.

For mild to moderate symptoms, non-surgical treatment is often effective. A wrist splint worn at night keeps the wrist straight and relieves night-time symptoms for many people. A corticosteroid injection into the carpal tunnel can reduce swelling and give relief, sometimes for a prolonged period. Activity modification helps where specific tasks aggravate symptoms, and any contributing condition, such as an underactive thyroid, is treated. Symptoms that come on in pregnancy often settle after delivery.

When symptoms are severe, persistent despite non-surgical measures, or where there is nerve damage with numbness or muscle wasting, surgery to release the pressure is recommended. Carpal tunnel release is a common, usually short operation, most often performed under local anaesthetic, in which the transverse carpal ligament is divided to enlarge the tunnel and take the pressure off the nerve. It can be done through a small open incision or with an endoscope; good-quality evidence shows both approaches give similar long-term results. Tingling and night symptoms often improve quickly, while numbness and strength recover more gradually.

Most people do very well after carpal tunnel release, particularly when it is carried out before the nerve has been severely or long-term damaged. Night symptoms and tingling frequently improve within days to weeks; where there has been long-standing numbness or muscle wasting, recovery is slower and may be incomplete. The wound heals over a couple of weeks, with grip strength continuing to recover over the following weeks to months. Recurrence after a properly performed release is uncommon.

Carpal tunnel release is generally safe, but, as with any operation, there are small risks, including scar tenderness, temporary weakness of grip, wound problems, and, rarely, incomplete relief or injury to nearby structures. Where the nerve has been severely damaged before surgery, some numbness or weakness can persist despite a successful release, which is one reason not to delay treatment of severe cases.

Myth: "Carpal tunnel syndrome is just from typing." Fact: It has many causes and associations; heavy repetitive use may contribute in some, but many people have no clear occupational cause.

Myth: "Surgery means a long recovery and a big scar." Fact: Release is usually a short operation, often under local anaesthetic, with night symptoms frequently improving within days to weeks.

Myth: "It will always go away on its own." Fact: Mild cases may settle, but severe or long-standing compression can cause lasting numbness and weakness if not treated.

This page is for general education and does not replace an individual assessment. Treatment depends on a person's specific symptoms, examination findings, imaging findings and overall health, and should always be discussed with a suitably qualified healthcare professional.

Carpal tunnel syndrome is the commonest of all the nerve entrapment conditions. It occurs when the median nerve — one of the main nerves to the hand — is squeezed as it passes through the carpal tunnel, a narrow passage at the front of the wrist bounded by the wrist bones and a tough band of tissue called the transverse carpal ligament. The median nerve supplies feeling to the thumb, index, middle and part of the ring finger, and powers some of the small muscles at the base of the thumb, so pressure on it produces a characteristic pattern of symptoms. Although it can be uncomfortable and, if severe, cause lasting weakness, carpal tunnel syndrome is very treatable. This page explains why it develops, how it is assessed, and how it is managed.

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• —Guideline note (place near references): The AAOS Clinical Practice Guideline on the Management of Carpal Tunnel Syndrome (2016, updated 2024) was the principal guideline source.

This information is for general patient education and is not a substitute for an individual consultation. Always seek personalised advice from a qualified spinal specialist.