CARPAL TUNNEL SYNDROME (CTS)
This condition results from excessive pressure on the median nerve as it passes through the carpal tunnel at the front of your wrist. This ‘tunnel’ is composed of the small bones of your wrist (the carpus) forming a C-shaped trench, and a layer of thick connective tissue as a roof over the top. Passing through this space is not only the median nerve, but also the long tendons allowing you to control your fingers. As the space is limited, and the tendons essentially non-compressible, anything that causes swelling within the space, or anything that grows into and occupies the space, will lead to squashing of the median nerve. Classically the median nerve supplies the sensation to your thumb, index and middle fingers, with a variable contribution to the ring finger. When a nerve is squashed, much like a computer cable, the outer casing is damaged and the outer fibres begin to fail. The symptoms tend to develop gradually and follow a common course of presentation, as follows:
- initially there are intermittent episodes of numbness and tingling, often described as pins and needles, or the feeling you get when you lay on a limb too long.
- these initial symptoms are often worse at night or with any activity putting a lot of pressure on the front of the wrist, such as gripping for long periods (driving, keyboard typing, or working with tools).
- initial symptoms usually resolve spontaneously, and are often helped by shaking the hand or letting it hang low.
- these episodes eventually become more frequent and last longer, until the numbers is permanent.
- pain fibres in the nerve can be triggered, and in some pain is a dominant feature. This pain is not always restricted to the hand – often your brain interprets a problem with the whole nerve and symptoms can refer up the arm.
- the deeper fibres, and those more resistant to compression, are that part of the median nerve that gives motor control to the small muscles of the hand. With persistent compression, these also gradually fail, and this presents as weakness of the hand and wasting, particularly of the muscle bulk to the base of the thumb (thenar eminence).
The median nerve starts in your body where your arm joins your torso, and with such a long path, there are other locations that it can be compressed and cause problems. As a general rule, if you maintain the sensation of your palm on the thumb side, but have lost sensation of the thumb and index on the palm side, the compression is likely at the wrist. Nerves and how the brain interprets them is not exact however, and the clinical picture can be confusing.
What can cause CTS?
There are many causes of CTS, but in most no specific pathology is identified. It is put down to overuse of the area in a patient whose normal anatomy means they are at increased risk of developing the problem. It can run in families, both due to common anatomy and inherited conditions. Some of the specific causes include:
- a ganglion in the carpal tunnel
- a benign tumour in the carpal tunnel
- synovitis or inflammation in the tunnel, as with rheumatoid arthritis, infection or trauma
- a fracture of the carpal bones that reduces the volume of the tunnel
- thickening of the carpal ligament roof, due to trauma, previous surgery, Dupuytren’s disease or other connective tissue disorder.
Are there any tests that can confirm that my problem is CTS?
Dr Host will take a thorough history and perform a focused clinical examination in order to identify where in the path of the nerve the problem is arising. In order to confirm the diagnosis, nerve conduction studies are often performed. This test will confirm the location within the nerve of the defect, and occasionally identifies those who have compression in multiple locations, where a single treatment may have yielded little benefit. An MRI may also be required if there is concern that other pathology may be present, such as a ganglion or benign tumour. An MRI is also of use if the problem is recurrent, or there has been any surgery or trauma to the area.
Are there any non-surgical treatment options for CTS?
Absolutely, and these should always be exhausted prior to considering surgery. It all depends on the exact cause of the nerve compression, but some treatments that can be trailed are:
- rest from aggravating activities such as typing, using pneumatic tools and prolonged gripping/driving.
- night time splints are used to hold the wrist straight. If the wrist flexes forward, this further compresses the already tight space and puts extra stress on the nerve. Holding the wrist straight for long periods can allow the nerve to recover, but as this is not always possible in the day, these tend to be worn at night.
– anti-inflammatory medications can be trialled, but often have little long term impact.
– corticosteroid injections of the carpal tunnel can alleviate symptoms in those where inflammation is a key
- component, and are often used as a measure to delay the need for surgery.
If the non-operative treatments are not working, what surgery is available?
The surgical solution to CTS is quite quick and simple – it involves dividing the thick layer of connective tissue forming the roof of the tunnel, and allowing the C-shape of the bony elements to spring outwards. The roof does re-form with scar tissue, but with an overall increased space in the tunnel. As such, the nerve compression is relieved.
Will my symptoms resolve quickly?
A lot of patients do report quite rapid resolution of their pain and numbness, but this depends on the amount of damage done to the nerve whilst it was squashed. Generally, if there has been numbness alone, the symptoms will resolve with time. If there has been weakness or wasting, then the recovery is less predictable, and often some deficit remains permanently.
How long will I need to take off work?
It is recommended that you take at least 2 weeks off work, as this allows for healing of the wound on your palm. It is not a great location to have a wound as you can imagine, and though it will heal over 2 weeks, like many scars, it can remain quite tender for many more weeks. If your work requires you to grip a lot or use your palm for pushing or lifting, you may require a longer period off work.
Can the problem happen again?
Unfortunately yes – as the divided connective tissue heals, it can again restrict the space in the tunnel and lead to further symptoms of CTS. Thankfully, this is quite uncommon, with the vast majority of patients having no ongoing or recurrent symptoms.
What should I be concerned about following surgery?
If you have any of the following signs or symptoms, please contact Dr Host or your local GP for review:
- Increased redness, heat or swelling around your wounds.
- Raised temperature/fever.
- Persistent ooze from your wounds.
Where can I gain more information on carpal tunnel syndrome?