Carpal Tunnel Syndrome
The carpal tunnel is a narrow passageway in your wrist, about an inch wide. The bottom and sides of this tunnel are formed by wrist (carpal) bones. The top of the tunnel is covered by a strong band of connective tissue called the transverse carpal ligament. The median nerve is one of the main nerves of your hand. It controls feeling in the palm side of your thumb, index, middle, and ring fingers. Along with the nine tendons that bend your fingers, the median nerve travels from your forearm into your hand through the narrow carpal tunnel.
Carpal tunnel syndrome is a condition in which the median nerve is squeezed or pinched where it passes through the wrist. The reason for this is usually unknown. Possible causes include: swelling of the tendon lining, joint dislocations, fractures, or arthritis. Fluid retention in pregnancy can also cause swelling in the tunnel. The median nerve controls some of the muscles that move the thumb and it carries information back to the brain about sensations in your thumb and fingers.
When the nerve is squeezed it can cause pain, aching, tingling or numbness in the affected hand. The symptoms tend to be worse at night and may disturb your sleep, but you may notice it most when you wake up in the morning. Hanging your hand out of bed and shaking it around will often relieve the pain and tingling.
You may not notice the problem at all during the day, though certain activities – such as writing, typing, DIY or housework – can bring on symptoms.
• Tingling of the thumb and fingers (not the little finger)
• Numbness in the thumb and fingers (not the little finger)
• Aching in the thumb, perhaps moving up as far as the neck
• Burning pain from the wrist to the fingers
• Change in touch or temperature sensation
• Clumsiness in the hands
• Weakness of grip, ability to pinch and other thumb actions
• Swelling of the hand and forearm
• Change in sweat functions of the hand (American Physical Therapy Association)
What causes Carpal Tunnel Syndrome?
The median nerve is very sensitive to pressure, and it may not be possible to say what the cause is in your particular case. However, some of the possible causes are:
• Any form of arthritis in the wrist if there is swelling of the wrist joint or the tendons that run through the carpal tunnel
• Hormonal changes during pregnancy – these can sometimes affect connective tissues and so put pressure on the nerve
• An underactive thyroid gland
• A fracture of the wrist
• Occasionally, some medications can cause it, particularly exemestane and anastrazole (treatments for breast cancer).
Your risk of developing carpal tunnel syndrome may be greater if your job places heavy demands on your wrist, or if you use vibrating tools.
Ecchymosis or abrasions on the wrists and hands suggest an acute injury to the tissue, including the median nerve, as the etiology. Bony abnormalities, such as boutonniere deformity, swan neck deformity, and ulnar deviation of the wrist, suggest rheumatoid arthritis whereas carpal or distal phalanx bossing suggests osteoarthritis. The naratrophy usually occurs only with severe, chronic carpal tunnel syndrome, and is more commonly associated with other neuropathy syndromes and carpometacarpal arthritis
Patients should be evaluated for the presence of hypalgesia (diminished ability to perceive painful stimuli) along the palmar aspect of the index finger compared with the ipsilateral little finger of the affected hand. A two-point discrimination test, in which the inability to discriminate points less than 6 mm a part is considered abnormal, can be performed with a caliper. The abductor pollicis brevis may display notable weakness on strength testing. The physician can observe this weakness by instructing the patient to raise his or her thumb perpendicular to the palm as the physician applies downward pressure on the distal phalanx, resisting thumb abduction
Phalen maneuver and Tinel sign have been used to observe for reproduction of the patient’s symptoms when the wrist is placed inflexion or when it is percussed on the volar surface, respectively. However, Phalen maneuver, Tinel sign, presence of the naratrophy, and history of nocturnal paresthesia have little diagnostic value compared with other history and examination findings.
What is the treatment?
Bracing or splinting
You may be given a splint to wear at night to prevent you from bending your wrist and compressing the nerve. Your therapist may advise you on how you position your hand when using it for prolonged activities at work or may give you some gentle exercises to do.
A steroid injection can be helpful, although the effect may wear off after weeks or months. A small quantity of steroid is injected into the carpal tunnel, which helps to reduce any swelling. The injection may rarely be uncomfortable, but it can be very effective. A steroid injection into the wrist joint itself may help if you have arthritis in your wrist.
Drugs like aspirin and ibuprofen reduce pain and swelling.
You may need surgery if there’s severe compression of the median nerve or if the numbness and pain doesn’t improve with other treatments.
Carpal tunnel release surgery relieves pain by reducing the pressure on the median nerve. Surgery usually takes place as a day case and you can expect to recover in less than a month. The operation is normally carried out under a local anaesthetic and usually leaves only a small scar.
If you’ve had carpal tunnel syndrome for a long time – especially if you have muscle-wasting or loss of sensation – the operation may not bring a complete recovery, but the pain should be greatly reduced. For most people surgery is very successful, but, as with all surgical treatments, some people will have complications
What are the risks with CTR surgery?
As with any surgery, you may be left with persistent pain, and/or stiffness following the operation, although normal use/exercise will make this less likely. There is also some risk of infection, or damage to nerves or blood vessels around the area. Please discuss this with your doctor if you would like more information.
You may have been referred to a physiotherapist for your carpal tunnel syndrome. They will provide you with some splints, teach you the following exercises, and educate you about posture. They may refer you onwards for an injection or consideration of surgery, depending on your symptoms.
Tendon gliding exercises
Start with a straight hand (1), move into position (2), hold for 2 seconds, then return to position (1). Repeat 10 times. Repeat the same process for positions (3), (4) and (5). Repeat five times daily.