Carpal Tunnel Syndrome
Carpal tunnel syndrome (CTS) is one of the most common types of nerve compression syndrome that manifests as a progressively worsening numbness or “tingling” sensation felt in the thumb, index finger, middle finger, and the thumb side of the ring finger that may be accompanied by pain.
This condition may also result in weakness when attempting to grip objects and is caused by excessive pressure being placed on the median nerve as it passes through the wrist into the hand.
The carpal tunnel and median nerve
The carpal tunnel (carpal canal) is formed by the carpal bones and the transverse carpal ligament, it is a narrow passageway across the wrist that the median nerve and tendons pass through to enter the hand.
The median nerve is a peripheral nerve that provides sensation to the thumb, index finger, middle finger and the thumb side of the ring finger. Unlike tendonitis that is caused by inflammation of the tendons/tendon sheath, the pain experienced when suffering from CTS is caused by the compression of the median nerve as it passes through the carpal tunnel.
Causes and Risk Factors
Carpal tunnel syndrome typically does not occur due to a single specific cause, it is instead, usually caused by a combination/culmination of contributing factors that result in the narrowing of the carpal tunnel such as:
- Repetitive movement of the wrist/hands
- Extreme or unnatural wrist movements that force the wrist into awkward positions
- Arthritic diseases
- Injury/trauma to the wrist
- Pre-existing medical conditions (Diabetes and obesity)
- Old age
- Fluid retention in the wrist due to pregnancy or menopause (hormonal changes)
Job/hobby related risk – Individuals with jobs that require frequent and repetitive movement of their wrist and/or grasping movement with their hands (athletes who participate sports like tennis or rock-climbing), or individuals with jobs that frequently require them to carry out high-force and physically intensive actions with their hands (construction workers who use power tools or do hammering), have the highest risk of developing CTS. Such repetitive wrist motions over a prolonged period may cause aggravation to the tendons in their wrist, resulting in swelling that puts pressure on the median nerve.
Carpal tunnel syndrome in desk bound workers – CTS is also common in individuals who spend a great amount of time using the keyboard or texting. Small but frequent and repetitive movements of the wrist and hands can also stress the tendons and cause pressure on the median nerve; CTS is known to be a notoriously prevalent medical condition among office workers, writers, and digital artists.
Arthritis – Arthritis is a disorder that causes inflammation or swelling of the joints. Inflammation of the tendons passing through the carpal tunnel of the wrist can squeeze the median nerve, leading to the development of carpal tunnel syndrome. Arthritis is a common contributing factor of CTS development in older individuals.
Diabetes and obesity – Certain pre-existing medical conditions can increase the risk of developing CTS. In individuals with diabetes, blood sugar may attach to the tendon proteins to cause inflammation of the tendons. Obesity may increase the risk of diabetes in addition to increasing the risk of CTS due to the build up of excess fat tissue within the carpal tunnel, gradually narrowing the tunnel and squeezing the median nerve.
Acute carpal tunnel syndrome
Acute CTS is primarily caused by blunt trauma to the wrist; examples of blunt trauma injuries include dislocation or factures to the wrist. Unlike chronic CTS which is caused gradually by constant exposure to risk factors, acute CTS usually has a know cause (for example, a wrist fracture) and develops spontaneously as a direct result of the cause (the wrist fracture).
Trauma to the wrist can deform the carpal bones and/or cause inflammation to the tendons and tissue running through the carpal tunnel, reducing the space inside the carpal tunnel and putting pressure on the median nerve. Depending on how severe the injury to the wrist is, acute CTS may require surgical decompression or release of the carpal tunnel to resolve.
Carpal tunnel syndrome in women
Carpal tunnel syndrome is more common in women compared to men due to the relatively smaller carpal tunnel area in women. Similarly, individuals with the genetic predisposition for having smaller wrists are also more likely to suffer from CTS.
Hormonal changes during pregnancy and menopause may also affect fluid retention; build-up of fluid can increase the pressure in the carpal tunnel, leading to median nerve irritation. While pregnant women are unfortunately more susceptible to CTS, CTS associated with pregnancy typically resolves on its own after pregnancy.
Carpal tunnel syndrome can also develop postpartum in a similar manner to de Quervain tenosynovitis due to and frequent stress being placed on the wrist and hands when supporting the weight of the baby during breastfeeding or bonding.
Signs And Symptoms Of Carpal Tunnel Syndrome
Numbness or tingling (pins and needles) in the thumb, index finger, middle finger, and the thumb side of the ring finger of one or both hands is the main symptom of carpal tunnel syndrome. Symptom of CTS typically start gradually but can worsen and travel up the arm from the wrist in some cases. Pain or a “burning” sensation can also accompany the numbness felt, with the pain often being reported to be worse at night and interrupting the sleep of patients.
Weakness in the hand and wrist, resulting in weakness or difficulty when attempting to grip objects with one or both hands, is another symptom of CTS. If left untreated CTS, can lead to muscle atrophy (shrinkage) of the muscles at the base of the thumb.
Stages of carpal tunnel syndrome
Carpal tunnel syndrome can be classified into three stages of general clinical severity: Mild, Moderate, and Severe.
Mild – Sporadic numbness and tingling sensation felt. Mild CTS is associated with the overexertion of the wrist, symptoms can usually be improved by resting the wrist/hand.
Moderate – Constant/chronic numbness and tingling sensation felt, the patient may start experiencing weakness or difficulty when attempting to grip objects.
Severe – Numbness to the point of extreme loss of sensation in the wrist/hand accompanied by possible atrophy of the muscles at the base of the thumb.
Symptoms of carpal tunnel syndrome can seem similar to the symptoms of de Quervain tenosynovitis or trigger finger due to all three conditions affecting similar areas of the hand/wrist and having similar root causes. For an accurate diagnosis, it is advisable to consult a trained medical professional from a reputable aesthetic clinic.
Carpal tunnel syndrome can be diagnosed via physical examination or medical scans. During a physical examination, the doctor may perform the following tests:
Tinel’s sign test – The doctor will tap the median nerve to observe if the patient feels a tingling sensation in their fingers.
Wrist flexion test – Also known as a Phalen test. During this test, the doctor will ask the patient to rest their elbow(s) on a table and allow their wrist to fall forward naturally. If the patient suffers from CTS, numbness and a tingling sensation should be felt by the patient within a minute of the wrist falling naturally forward.
In addition to performing a physical examination, the doctor may also order for medical scans to be ran on the patient to solidify the diagnosis. Common scans used to diagnose CTS include:
- X-ray – Determines if arthritis or trauma is a possible cause
- Ultrasound – Visualises the bones and nerve to determine if the nerve is being compressed
- Electromyography (EMG) – Nerve conduction study involving passing a mall shock through the median nerve to determine if electrical impulses are delayed in the carpal tunnel
Depending on the severity and probable cause of carpal tunnel syndrome, the condition can be treated non-surgically or surgically. Non-surgical treatment typically works to reduce the strain place on the wrist/hand to alleviate the symptoms of CTS or alleviate the symptoms via reducing swelling and irritation in the carpal tunnel to stop the nerve from being compressed, while surgical treatment directly stops the median nerve from being compressed by releasing the ligament that is pressing on the nerve.
Non-surgical treatment can be effective for treating mild to moderate CTS. If a patient is not responsive to non-surgical treatment, surgical treatment can be considered.
Splints – A removeable splint holding the wrist still during sleep can be worn to relieve nighttime symptoms of numbness, tingling, and pain. Wearing the splint during the day when performing tasks like using the keyboard, writing, or drawing can also reduce the strain placed on the wrist and alleviate symptoms of CTS.
This method has the additional benefit of being friendly towards pregnant women or nursing mothers who might not be able to take oral medication.
Lifestyle change – For mild cases of CTS, a change in activity level (for example, reducing the time spent on a hobby) can be enough alleviate symptoms without any further medical intervention.
Medication – Non-steroidal anti-inflammatory drugs (NSAIDs) can be prescribed by the doctor to reduce inflammation and relieve pain. However, NSAIDs are often a short-term solution to relieving the symptoms of CTS.
Corticosteroids – Corticosteroids can be administered orally or via an injection into the carpal tunnel to reduce swelling and inflammation, and thus, reduce the pressure on the median nerve. Non-surgical treatment that targets inflammations is usually more effective when treating CTS caused by inflammatory arthritis.
Surgical treatment may be appropriate for patients suffering from severe CTS, or for patients who do not get adequate relief from non-surgical treatment options.
Carpal tunnel syndrome is caused by the compression of the median nerve as it passes through the carpal tunnel. The aim of carpal tunnel release surgery is thus to cut through the ligament that is pressing on the median nerve to relieve pressure or increase size of the wrist tunnel.
During the procedure, the surgeon will make an incision in the palm of the affected hand and subsequently cut/release the transverse carpal ligament (the ligament that forms the roof of the carpal tunnel) to increases the size of the carpal tunnel and relieve pressure on the median nerve.
Carpal tunnel release surgery can be done under general anaesthesia or under local anaesthesia, and are two types of carpal tunnel release surgery: open carpal tunnel release and endoscopic carpal tunnel release.
Open Carpal Tunnel Release (OCTR) – OCTR is the most common type of carpal tunnel release surgery and medical studies show that it has a high success rate of up to 90%.
During an OCTR surgery the surgeon will make an incision in the palm of the affected hand directly above the transverse carpal ligament to expose it, the transverse carpal ligament is then cut to make more room for the median nerve.
Endoscopic Carpal Tunnel Release (ECTR) – During an ECTR surgery, the transverse carpal ligament is not exposed. The surgeon will instead make a small incision at the crease of the wrist to insert an endoscope (small flexible device with a camera head and light) and cutting instrument, the transverse carpal ligament is then released using the cutting instrument under the visual guidance of the endoscope.
This type of carpal tunnel release surgery is know to be more comfortable as it produces less wound pain during recovery.