Carpal tunnel syndrome (CTS) is the most common nerve entrapment condition in the upper limb, affecting between 7 and 19% of the UK population. It occurs when the median nerve becomes compressed as it passes through the carpal tunnel at the wrist. The median nerve is one of the main nerves supplying feeling and movement to the hand.
If you have been experiencing tingling, numbness or pain in your hand and fingers - particularly at night - carpal tunnel syndrome may be the cause. The good news is that it is a highly treatable condition, especially when caught early.
What is the carpal tunnel?
The carpal tunnel is a narrow channel on the palm side of your wrist, formed by the wrist bones (carpals) on three sides and a thick ligament (the flexor retinaculum) across the top. Nine flexor tendons and the median nerve pass through this tunnel into the hand.
When the contents of the tunnel become compressed due to swelling, inflammation or a change in the tunnel’s shape, the median nerve is squeezed and the characteristic symptoms of carpal tunnel syndrome follow.
What causes carpal tunnel syndrome?
CTS does not always have a single clear cause. It is usually the result of a combination of factors that increase pressure within the carpal tunnel:
- Repetitive hand and wrist use: repeated wrist flexion or the use of vibrating hand tools at work or at home.
- Sustained wrist positions: sleeping with bent wrists or prolonged keyboard and mouse use.
- Medical conditions: diabetes, thyroid disorders, rheumatoid arthritis and kidney disease are all associated with CTS.
- Hormonal changes: fluid retention during pregnancy or the menopause can increase pressure within the tunnel.
- Wrist anatomy: previous wrist fractures, dislocations or a naturally narrow tunnel.
- Age and sex: CTS is more common in women aged 40 to 60, though it can affect anyone.
What are the symptoms?
The median nerve supplies sensation to the thumb, index finger, middle finger and half of the ring finger. Symptoms of CTS typically affect these fingers and may include:
- Tingling and numbness in the thumb, index, middle and ring fingers - often described as pins and needles.
- Pain in the hand, wrist or forearm, sometimes radiating up the arm.
- Night symptoms: waking at night with tingling or pain, often relieved by shaking or hanging the hand over the side of the bed.
- Weakness in grip or pinch making fine tasks such as doing up buttons, holding a cup or turning a key more difficult.
- Dropping objects due to reduced strength or sensation in the hand.
- Clumsiness: a general sense of the hand not working as well as it should.
Symptoms are often worse at night and during activities that involve holding the wrist in a flexed position such as driving, reading or using a phone.
What happens if carpal tunnel syndrome is left untreated?
Without treatment, CTS tends to progress. Mild symptoms that begin as intermittent tingling can worsen to constant numbness and significant hand weakness. In severe or longstanding cases, the muscles at the base of the thumb (the thenar muscles) can waste away. This is a change that may be difficult or impossible to reverse even with successful treatment.
Early intervention is important. Treatment started within the first six weeks of symptoms can produce significant improvement and prevent progression to more severe disease.
How is carpal tunnel syndrome diagnosed?
Diagnosis is primarily clinical, based on your history and a physical examination. A Hand Therapist or doctor will assess your symptoms and perform a number of clinical tests:
- Phalen’s test: holding the wrist in a flexed position for up to 60 seconds to reproduce symptoms.
- Durkan’s test: applying direct pressure over the carpal tunnel for up to 30 seconds.
- Tinel’s sign: tapping over the carpal tunnel to produce tingling in the fingers.
These tests combined with a detailed symptom history are usually sufficient to confirm the diagnosis. In some cases, further investigations may be recommended:
- Nerve conduction studies (NCS): the most objective test, measuring the speed of electrical signals through the median nerve.
- Ultrasound: can assess the size of the median nerve and identify swelling.
- MRI: used in complex or atypical cases to examine the tunnel contents in detail.
What are the treatment options?
Non-surgical treatment
For mild to moderate CTS, non-operative treatment is the recommended first approach. The majority of patients respond well without the need for surgery.
Splinting is one of the most effective non-operative treatments. A custom-made or off-the-shelf splint holds the wrist in a neutral position, preventing the compression of the nerve that occurs with wrist flexion. Splints are typically worn at night. A Hand Therapist can fabricate a custom orthoses shaped precisely to your wrist for optimal comfort and effectiveness.
Therapeutic exercises including tendon gliding and nerve gliding techniques help to improve the movement of the flexor tendons and median nerve through the carpal tunnel, reducing friction and neural tension. Ms Razo will prescribe a specific exercise programme tailored to your presentation.
Activity modification & ergonomic advice forms an important part of management. This includes identifying and reducing the activities and postures that aggravate your symptoms, advice on workstation setup and keyboard positioning and guidance on how to modify daily tasks to protect the wrist.
Corticosteroid injection into the carpal tunnel can provide significant temporary relief by reducing inflammation. This is typically performed by a doctor and can be a useful treatment in its own right or as a bridge to other management.
Surgical treatment
If conservative treatment has not provided sufficient relief, or in cases of severe CTS with significant muscle weakness or wasting, surgical decompression (carpal tunnel release) may be recommended. This is a common and generally very effective procedure, performed as day surgery under local anaesthetic.
The surgery involves dividing the flexor retinaculum, the ligament forming the roof of the carpal tunnel, to relieve pressure on the median nerve. It can be performed as an open procedure or endoscopically. Post-surgical Hand Therapy is important to optimise recovery of strength and function following the operation.
How can Hand Therapy help?
A Hand Therapist plays a central role in both the non-operataive management of CTS and post-surgical rehabilitation. Treatment may include:
- Custom splint fabrication for night use
- A tailored exercise programme including nerve and tendon gliding
- Activity modification and ergonomic advice
- Scar management and desensitisation following surgery
- Grip and pinch strength rehabilitation
- Guidance on returning to work and daily activities
If you are experiencing symptoms of carpal tunnel syndrome, early specialist assessment is important. Ms Razo offers prompt appointments with no waiting list. You can book a consultation or contact the clinic to discuss your symptoms.