Carpal Tunnel Syndrome
What is Carpal Tunnel Syndrome?
Carpal tunnel syndrome is a painful disorder of the hand caused by pressure on your median nerve as it runs through the carpal tunnel of the wrist. Symptoms include numbness, pins and needles, and pain (particularly at night). Anything that causes swelling inside the wrist can cause carpal tunnel syndrome, including repetitive hand movements, pregnancy and arthritis.
What is Your Carpal Tunnel?
Your carpal tunnel protects vital structures such as the median nerve, blood vessels and tendons as they pass to and from your hand. The palm side of your wrist has a band of strong ligaments (flexor retinaculum) that attach to the carpal (wrist) bones at either side. The rear of the tunnel is a curved compilation of the wrist bones.
What's the Cause of Carpal Tunnel Syndrome?
Carpal Tunnel Syndrome symptoms begin when the pressure inside the tunnel becomes too high. This results in your median nerve becoming compressed as it passes through the small tunnel.
The carpal tunnel pressure increase occurs when either of two things happens:
Both of these situations increase the pressure on the nerve, leading to the carpal tunnel symptoms.
Other Common Causes of Carpal Tunnel Syndrome
Frequently, the median nerve is compressed elsewhere along its path - not in the carpal tunnel - and replicates carpal tunnel symptoms. Most often compression occurs in your neck but can occur anywhere along the nerve path as it travels to your hand. This entrapment predisposes the nerve to develop carpal tunnel symptoms.
How does this occur?
Healthy nerves have a supply of fluid called axoplasmic fluid, which provides the nerve with nutrients. Normally, a pressure of about 70 mmHg propels this fluid slowly along the length of the nerve. However, if the nerve is slightly squashed (e.g. by a bulging neck disc) then the flow of this fluid is interrupted. Your nerve will starve and you may experience carpal tunnel symptoms.
It is important to confirm the site of your nerve compression. There are many patients over the years who have had carpal tunnel surgery performed without benefit because the carpal tunnel symptoms originated from nerve compression elsewhere. This condition is known as “double crush syndrome”.
Potential Compression Sources
Your symptoms can originate from elsewhere along the median nerve. This source is frequently overlooked and could save you from unsuccessful surgery. Your lower cervical spine especially C6, C7, C8 and T1 should be thoroughly examined by your physiotherapist. This is version “double crush syndrome” and there is an increased likelihood of carpal tunnel syndrome in these patients. Kwon et al (2006).
Your nerves should freely travel along their pathways between your spine and your fingers. Any interference of their slide mobility could cause symptoms eg scar tissue, tight muscles. Your physiotherapist can assess your neurodynamics for abnormalities. Tal-Akabi & Rushton (2000).
Hormone imbalances can cause swelling of the hands and feet, as evidenced by the condition's prevalence in middle-aged or pregnant women.
Gripping, Repetition and Microvibration
Occupations associated with repetitive wrist flexion and extension activities, vibratory tools, and gripping have a high incidence of carpal tunnel syndrome.
What're the Symptoms of Carpal Tunnel Syndrome?
Carpal Tunnel Syndrome (CTS) sufferers will usually experience the following symptoms in their hand or fingers:
The symptoms are usually worse at night and your grip will weaken as the condition progresses. Eventually you will notice muscle atrophy of the thenar (thumb) muscles and loss of hand function or clumsiness. If this sounds like you, suspect carpal tunnel syndrome.
Shaking the wrist may ease symptoms temporarily. Zhao & Burke (2008).
How is Carpal Tunnel Syndrome Diagnosed?
Your physiotherapist or doctor will generally diagnose carpal tunnel syndrome based on your symptoms. They use various tests such as Phalen’s test, Tinel’s test or the wrist flexion/median nerve compression test that compress the carpal tunnel. It is also important to thoroughly examine your lower neck and upper back joints, plus your nerve tissue mobility - neurodynamics.
Your doctor may refer you for nerve conduction studies or EMG studies to quantify if your nerve electrical impulses are slowed by compression of the carpal tunnel or further up the arm. Craig & Richardson (2011).
Ultrasound may reveal median nerve enlargement. X-ray may identify coexisting pathologies. MRI, CT scans are not normally required. Hobson-Webb & Padua (2009).
Carpal Tunnel Syndrome Treatment
Rest & Patient Education
Resting from the aggravating cause is important. Education and awareness about what the symptoms and what positions or activities potentially cause carpal tunnel syndrome is important. Sim et al (2011).
Night Wrist Splint
A nighttime wrist splint is beneficial to eliminate wrist bending and therefore carpal tunnel symptoms. Muller et al (2004). Your physiotherapist may recommend a splint. A suitable carpal tunnel wrist splint can be found here: carpal tunnel brace
Physiotherapy is beneficial for most carpal tunnel sufferers especially in mild to moderate cases.
Your physiotherapist will address:
Ultrasound Therapy, Acupuncture, Massage & Yoga
Ultrasound therapy has been shown to assist carpal tunnel syndrome. Huisstede et al (2010). Acupuncture has been shown to decrease carpal tunnel pain. Sim et al (2011), Kumnerddee & Kaewtong (2010), Yang et al (2011).
Targeted massage has been shown to assist grip strength in CTS sufferers. Moraska (2008).
Yoga focusing on upper body flexibility has been shown to improve grip strength quicker than wrist splints. Garfinkel et al (1998).
If the carpal tunnel has been caused at work, then an ergonomic assessment of the workplace and work practices may be worthwhile to prevent a recurrence. Activity modification may be required. Larson & Ellexson (2000).
A TENS machine (transcutaneous electrical muscle stimulation) has been shown to ease the pain associated with carpal tunnel syndrome. Kara et al (2010). More information about TENS machines can be found here: Tens Machine
Carpal Tunnel Surgery
The American Academy of Orthopaedic Surgeons (AAOS) recommends that conservative treatment is attempted initially. Keith et al (2009).
Before you undertake carpal tunnel surgery it is important that you have checked all the other possible sources. As mentioned earlier, the resolution of carpal tunnel syndrome after surgery is often temporary or incomplete if the symptoms originate elsewhere. As a general rule carpal surgery will normally occur after 6 to 12 months of conservative treatment such as physiotherapy and wrist splints. However, surgery may be considered within a few months if neurological symptoms deteriorate quickly.
Even if your symptoms are relieved at the carpal tunnel - either with splints or with surgery - it may only be a temporary solution, if there is another location where the nerve has “double crush syndrome”. Obviously, in these cases, treatment of the whole nerve path is extremely important to alleviate symptoms.
Carpal Tunnel Syndrome Prognosis?
Mild to moderate sufferers of carpal tunnel syndrome have a favourable prognosis from conservative treatment. The best results occur within the first three months of treatment. Severe cases, especially those with thenar muscle atrophy, are more likely to require surgical release of the carpal tunnel. Shi & MacDermid (2011).
Chronic carpal tunnel syndrome can in neural fibrosis, resulting in permanent nerve damage that will not respond to conservative or surgical treatment. Boscheinen-Morrin & Conolly (2001).
For more specific advice please consult your physiotherapist or doctor.
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