Carpal Tunnel Syndrome (CTS)
What is Carpal Tunnel Syndrome?
Carpal Tunnel Syndrome (CTS) is a painful and sometimes disabling condition involving the compression of the median nerve as it passes through the carpal tunnel, a rigid compartment formed by the carpal bones of the hand at the base of the palm. The tunnel is bounded on the top by a sheath-like or fibrous structure called the flexor retinaculum and the transverse carpel ligament. The tunnel itself is approximately the diameter of the index finger and must accommodate the passage of nine flexor tendons, the median nerve, arteries and lymphatic vessels. Normally, these structures glide past each other to provide function to the fingers and wrist.
What are the Symptoms of Carpal Tunnel Syndrome?
The condition usually comes on gradually, with a vague aching of the wrist, and some times above and below the wrist. There may also be a tingling into the area supplied by the median verve. This includes the thumb, the first two fingers and half of the third finger. If the condition is not resolved the long-term effects can be permanent nerve damage resulting in numbness and weakness in the hand with atrophy or wasting of the muscles below the wrist.
The patient may initially experience the symptoms during sleeping hours when fluid builds up while the hand is resting causing pressure on the nerve. Flexed wrist postures while sleeping will also bring on the symptoms. As the condition worsens the symptoms are likely to occur during the day. At this point there could be permanent nerve damage and a buildup of scar tissue around the nerve.
What are the Causes of Carpal Tunnel Syndrome?
The condition is caused by anything that increases pressure on the median nerve as it passes through the tunnel. As a work-related disorder CTS is the most common form of repetitive strain injury (RSI) otherwise known as cumulative trauma disorder (CTD) and is usually brought on by repetitive specialized movements involving excessive forces. The work may require awkward postures particularly flexion and extension of the wrist.
A key factor is the lack of sufficient rest periods to allow for a sufficient recovery of the muscles and tendons. The prolonged static contraction of the forearm muscles constricts the small blood vessels thereby inhibiting blood flow. The result is the destruction of tissue and the infiltration of inflammatory substances into the area. There is then a concomitant increase in fluid pressure and a resultant decrease in blood flow to the nerve. The effect is a recurrent injury to the nerve.
Women tend to have a higher incidence than men possibly due to the fact that they have smaller carpel bones and a resulting decreased tunnel space. Women also tend to have a tendency toward tissue fluid build-up due to fluctuations in hormone levels. The condition is also associated with certain medical conditions such as wrist fractures and other traumas, rheumatoid arthritis, diabetes, hypothyroidism, pregnancy, obesity and sarcoidosis.
How is Carpel Tunnel Syndrome Prevented and Treated?
Conventional treatments include anti-inflammatory medications, cortisone injections, heat and cold therapy, wrist splints (during sleeping and waking hours), ultrasound therapy, stretching and strengthening exercises. When symptoms persist surgery is usually considered especially when atrophy is evident and there is persistent loss of sensation.
Prevention is most desirable before the problem begins. Activities involving repetitious hand movements done with significant force or awkward postures including vibrating and impact tools should not be performed more than two to four hours. Preventative measures include vitamin B6 (not over 100 mgs per day) for those who have a propensity for developing edema. Workers should take frequent planned breaks for rest and stretching exercises. They should use ergonomically designed tools and split-keyboards that maintain neutral hand posture.
1) Davies MD, John A. K. “Carpal Tunnel Syndrome.”
2) Miller, Karl E. “Wrist Splinting in Patients with Carpal Tunnel Syndrome.” American Family Physician, Oct 1, 2000
3) Sequeira, Winston. “Yoga in Treatment of Carpal Tunnel Syndrome.” Lancet, February 27, 1999
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