Carpal Tunnel Syndrome
Carpal tunnel syndrome is disorder of the hand and wrist caused by swollen tendons in the wrist, resulting from repeated and / or forceful motion of the hands and wrists.
The median nerve extends to the hand through a tunnel of bones and tendons in the wrist. When a person repeats the same hand and wrist movements day in and day out, the excess strain causes the tendons to swell and become inflamed. The swollen tendons press on the median nerve, which causes pain, numbness, tingling, or clumsiness in the hand. This is called carpal tunnel syndrome.
Carpal tunnel syndrome is relatively common. It may occur in one or both hands, and is more common in women. Some of the common causes and other medical conditions that may cause the syndrome are:
Repeated and forceful grasping or pinching with the hands Repeated use of vibrating tools or machinery Repeated bending of the wrist Broken or dislocated bones in the wrist, which can cause swelling. Arthritis Thyroid gland imbalance Diabetes Hormonal changes of menopause Pregnancy
Examples of people at risk for repetitive motion injury are typists, carpenters, grocery checkers, assembly line workers, meat packers, and mechanics.
Hobbies / activities such as sewing, gardening, racquet sports, and piano playing may also cause a repetitive motion injury.
Signs and Symptoms
A person may have symptoms in one or both of the hands, but the hand used most often will usually show symptoms first. A person may experience some or all of the following signs and symptoms:
Numbness or tingling in the hand and fingers (thumb, index and middle) Pain in the wrist, palm or forearm, or even in the shoulder More numbness or pain at night than during the day More pain as the hand or wrist is used Trouble gripping objects Dropping objects Weakness in the thumb
Detection and Diagnosis
The doctor will examine the wrist for limited movement (called the Phalen=s sign test), and gently tap on the wrist to check for the "pins and needles" sensation and pain (called the Tinel's sign test). The doctor will have the person hold their wrists in a downward position for about one minute to see if the symptoms occur.
In some cases, the doctor may order tests of the median nerve or muscles of the hand and forearm. Nerve conduction velocity (NCV): a test that measures how fast nerve impulses move through the nerve. The doctor gives a mild electrical shock to stimulate a particular nerve. The shock is administered through the skin and underlying tissue. After each shock, a recording electrode that=s placed a set distance from the site of the shock detects the response from the stimulated nerve. The time between the shock and the response is measured.
Electro myography (EMG): a test in which the electrical activity in a muscle is analysed. By placing small electrodes on the skin over the muscle or inserting needle electrodes into the muscle the electrical activity of the muscle as it contracts and rests are recorded.
Mild cases are usually treated by applying a wrist splint or brace, especially at night. This rests the wrist and allows the swollen and inflamed tendons to shrink (taking pressure off the median nerve).
The doctor may also prescribe an anti-inflammatory medication such as ibuprofen (Advil, Medipren, Motrin, Nuprin), naproxen (Aleve) or aspirin to reduce the swelling.
If the swelling, inflammation, or pain is not relieved with resting the wrist and an anti-inflammatory medication, the doctor may inject cortisone into the carpal tunnel.
This medicine spreads around the swollen tendon, shrinking it and relieving pressure on the median nerve. The dose of cortisone is very small and usually has no side effects.
Surgery is usually recommended if any of the following conditions are present:
Conservative treatments do not work, and the person is still having symptoms Thenar atrophy (weakness of the thumb muscles) Carpal tunnel syndrome with trauma Carpal tunnel syndrome mass (tumour)
There are different surgical procedures designed to relieve pressure on the median nerve:
Open carpal tunnel release:
A small incision is made in the palm of the hand and the palmar fascia (a membrane in the palm). The transverse carpal ligament is cut, thus taking pressure off of the median nerve.
Endoscopic carpal tunnel release: This procedure can also be done using a small lighted tube called an endoscope. With endoscopic carpal tunnel release a small fiberoptic scope is used to find the transverse carpal ligament, thus the palmar fascia is not cut.
Balloon carpal tunnel-plasty:
The procedure utilizes a balloon catheter (a small tube for passage into a structure), a pressure gauge, and a custom designed nerve protector that protects the median nerve and tunnel contents during the inflation. The balloon catheter is inserted into the carpal tunnel through an incision in the wrist and is inflated. This stretches the ligament and makes more room for the median nerve.
Possible surgical complications include postoperative infection, acute haematoma, arterial injury, direct injury to the median nerve, postoperative pain, stiffness, reflex sympathetic dystrophy, and recurrent carpal tunnel syndrome from incomplete transection of the transverse carpal ligament.
The surgery is usually done in an outpatient facility and the person can usually go home the same day.
The site of the operation is made numb with an anaesthetic injected either into the wrist and hand, or higher up the arm. Symptoms are usually relieved immediately or over a short period of time. The wrist is likely to be somewhat uncomfortable, and there may be some pain, but this should not last more than a day or two. If non-absorbable nylon stitches were used to close the incision, they will be removed once the incision is healed; absorbable stitches are not removed and will generally disappear in 2-4 weeks.
After surgery, use of the hand will be limited for a week or so. Usually, full use of the hand is achieved six weeks after surgery. The patient may need wrist splints to support the wrist for a short time after surgery.
The doctor will give exercises that are done to strengthen the fingers and keep the joints from becoming too stiff. These exercises should be started as soon as possible. Results from surgery are generally quite good if severe weakness had not already developed. Most people are able to resume normal activities after surgery. Avoid re?injuring the wrist by changing the way and how often repetitive movements are done, and by not putting too much strain on the wrist.
Exercise the wrists and hands before beginning repetitive shift work and after each break. A team of orthopaedic surgeons has developed the following exercises to help in preventing and controlling carpal tunnel syndrome:
1. Extend and stretch both wrists and fingers as if they are in a hand stand position. Hold for a count of 5.
2. Straighten both wrists and relax fingers
3. Make a tight fist with both hands. Then bend both wrists down while keeping the fist. Hold for a count of 5.
4. Straighten both wrists and relax fingers, for a count of 5.
Repeat exercises 10 times, then hang arms loosely at side and shake them for a couple of seconds.
Type with arms parallel to the floor and wrists in neutral, "floating" above the keyboard. Adjust the height of the keyboard, desktop or chair to eliminate any cocking of the hands.
Don't rest wrists on the edge of the desk as this compresses the carpal area.
If you have a detachable keyboard with a long cord, change your position occasionally. For instance, rest the keyboard on your lap.
Consider a wrist rest, a soft pad that extends toward you from under the keyboard.
Switch from a conventional computer mouse to a track ball, which looks like a pool ball resting in a cup.
Use larger tool handles. Buy soft covers that enlarge tool handles, or make your own with duct tape and foam rubber.
Avoid working in the cold, when tendons are less flexible and more likely to become irritated and swollen.
Avoid repetition. Take a break lasting 5 to 10 minutes every hour and shorter pauses every 5 to 10 minutes.
Use power tools (e.g., screwdriver, drill) rather than manual whenever possible.
Glossary of Medical Terms
Phalen=s test: A physical test involving flexing a fully extended hand at the wrist Repetitive motion injury: tissue damage caused by repeated trauma to a particular area of soft tissue, including tendons and synovial sheaths. Tinel=s sign: tingling of the skin produced by pressing on or tapping a nerve that has been damaged or is healing after trauma.