Carpal tunnel syndrome: how can a plug help us understand it better?
Carpal tunnel syndrome is a very common condition, but one that is often poorly understood. We asked specialist hand surgeon, Mr Zulfi Rahimtoola, to explain what it is and how we can understand the condition better.
Using an analogy, let’s think about the wiring in a wall plug. When you open up the back of the plug you’ll find several wires, underneath a rubber bridge to keep everything neatly in place. Think of the plug as your hand, the wires as nerves running to your fingers and the rubber bridge as your carpal tunnel bridge (ligament) holding the wires in place.
A classic symptom of carpal tunnel is pins and needles in the thumb, index finger and middle finger of the hand. Going back to the plug analogy, if the bridge is too thick this presses down on the wires causing the electricity running through the wires to flicker. This is what is causing the pins and needles to occur. It becomes a syndrome when you get these symptoms more frequently. In carpal tunnel it is a “main wire” (the median nerve which runs underneath the carpal tunnel ligament) becoming irritated, giving you the same pins and needles sensation.
For most patients, they actually won’t notice any loss of function with their hands. In carpal tunnel syndrome the pins and needles will often be on the inside fingers of the hand. If there are sensations in the fourth finger or little finger, this is a sign it may be another “wire” (the ulnar nerve) or the so-called cubital tunnel syndrome instead.
Another classic symptom of carpal tunnel is difficulty sleeping at night. You may wake up needing to shake your hand down by your side to relieve the pins and needles. This is an instinctive reaction to try to increase the blood flow to the wrist, which helps to relieve the symptoms.
Patients have also described feeling pain, having a burning sensation and also numbness. Persistent numbness or lack of sensation usually means the symptoms are more serious and require quicker treatment. Patients with numbness often describe not being able to feel the buttons on their shirt or their earrings, so they may feel a bit clumsy. In these cases, it’s important to see a specialist as quickly as possible to prevent the symptoms from getting worse.
There has been lots of research around the causes and why people develop the condition. However, in more than 90% of cases it is simply unknown. The nerve may have become irritated or the carpal tunnel may have thickened, although it is unclear why this might be.
However, there are certain risk factors associated with the condition. For instance, those who are diabetic or have rheumatoid arthritis are more at risk. It can also be caused by a sudden change in activity or by trauma from a fall for example. Anything that leads to a forceful bending of the wrist can cause bruising on your nerve, which can in turn cause symptoms to occur.
For instance, if you’ve just started a new fitness regime and suddenly go to the gym every day, then lots of press-ups could increase the pressure on your nerve and you may develop signs of this condition. Even simply changing your car can mean you rest your elbow in a different position on your side panel door which may lead to symptoms.
Carpal tunnel syndrome is more common in patients over 30 years of age, particularly those in their 40s and 50s. However it can also affect between 15-20% of women during pregnancy. This is usually due to hormonal changes and the fact that fluids accumulate naturally in tighter areas such as the wrists, leading to compression of the nerves.
The treatments offered will very much depend on the patient’s history and severity of symptoms. Those with what we call ‘short onset symptoms’ may have only had issues for the last few months. They might have pins and needles and some difficulty sleeping for instance. In these cases, it’s a case of a quick consultation and trying non-surgical techniques first. For instance, wearing a splint at night can reduce symptoms as can simple recommendations for improving your posture during the day. Other treatments include physiotherapy and sometimes injections, although your consultant will recommend the best option for you.
If a patient is experiencing regular pins and needles, but also numbness in their fingers, then this indicates a more severe case. In addition, I will look out for any muscle weakness and reduced grip strength in the hand as this can be a classic sign of a chronic issue too. In these cases it may be more appropriate to recommend an operation, which we call “carpal tunnel release surgery”.
It’s important to note that regrettably there is a point of no return with carpal tunnel syndrome. If you experience numbness and weakness for a longer period of time, there is a point where irreversible damage is caused which surgery cannot fix. However, most patients will seek help before this point and there are lots of effective treatments to fully cure the condition.
The purpose of the operation is to make a small incision (usually around 1cm) into the wrist in order to open the carpal tunnel ligament, which releases the pressure on the nerves. Using another analogy, the surgery is much like permanently opening a drawbridge over a river – the boats will then be able to pass freely underneath. Or, in the case of the wall plug, so that the wires can fire off again.
The operation itself usually lasts less than 10 minutes and is done under a local anaesthetic. You’ll therefore be able to leave hospital on the same day. The wound will need to fully dry over the next 10-14 days, so it’s important the wound doesn’t get wet during this time. You will also wear a compression bandage after the operation and your stitches will then be removed at your follow-up appointment. I expect most patients to make a full recovery from surgery after approximately six weeks, returning to normal activities like they did before.
Quite simply, the main difference in symptoms is that pins and needles are present with carpal tunnel syndrome, but not with arthritis. There are rare cases where severe arthritis can put pressure on nerves to mimic the symptoms, but this is only in severe longstanding cases or if the patient has fractured their wrist for instance.
Arthritis is characterised by aching and pain, but not usually pins and needles. It is usually worse first thing in the morning, but symptoms will often wear off as your hands warm up during the day.