David S. Klein, M.D.

Carpal Tunnel Syndrome

CARPAL TUNNEL SYNDROME AND VARIANTS

Carpal Tunnel Syndrome is a condition that results from irritation and possible compression of the median nerve as it passes into the wrist. The largest nerve that passes from the forearm into the hand is called the "Median Nerve" and nerve impulses that permit sensation to portions of the hands and allow motor use (motion) of many muscles within the hand.

Damage to the Median Nerve can result from a variety of causes, including repetitive use, trauma, tendinitis, and can commonly result from undiagnosed thyroid conditions.

Surgery is sometimes necessary to correct a severe nerve pinch, but quite commonly, thoughtful and intelligent use of oral medications can remedy the situation without the need for surgery.

Anti-convulsant medications are generally used to treat "seizure" disorders, but these medications, if used carefully and in relatively low dosage, can lessen or eliminate the symptoms of carpal tunnel syndrome. Anti-inflammatory medications can treat inflammatory causes of nerve pinches, but often oral anti-inflammatory medications can actually worsen the problem by an interesting effect on the kidneys that enhances salt retention. The salt retention from the anti-inflammatories can worsen the "pinch," but this unwanted side-effect can be prevented with the use of low-dose diuretics (fluid pills.)

Carpal Tunnel Syndrome

Description:

Carpus is a word derived from the Greek word "karpos" which means "wrist." The wrist is surrounded by a band of fibrous tissue which normally functions as a support for the joint. The tight space between this fibrous band and the wrist bone is called the carpal tunnel. The carpal tunnel receives its name from the 8 bones in the wrist, called carpals, that form a tunnellike structure. The tunnel is filled with flexor tendons which control finger movement. It also provides a pathway for the median nerve to reach sensory cells in the hand. Repetitive flexing and extension of the wrist may cause a thickening of the protective sheaths which surround each of the tendons.

The swollen tendon sheaths, or tenosynovitis, apply increased pressure on the median nerve and produce Carpal Tunnel Syndrome (CTS).

The median nerve passes through the carpal tunnel to receive sensations from the thumb, index, and middle fingers of the hand. Any condition that causes swelling or a change in position of the tissue within the carpal tunnel can squeeze and irritate the median nerve. Irritation of the median nerve in this manner causes tingling and numbness of the thumb, index, and the middle fingers, a condition known as "carpal tunnel syndrome."Carpal tunnel syndrome is a common source of hand numbness and pain. It is more common in women than men and affects up to 10 percent of the population. It is caused by increased pressure on a nerve entering the hand through the confined space of the carpal tunnel.

The median nerve travels from the forearm into your hand through a tunnel in your wrist. The bottom and sides of this tunnel are formed by wrist bones and the top of the tunnel is covered by a strong band of connective tissue called a ligament. Your doctor may make the diagnosis by discussing your symptoms and examining you. If symptoms continue to bother you, electrical testing of the nerve function is often performed to help confirm the diagnosis and clarify the best treatment option in your case.

Symptoms:

The symptoms of CTS often first appear as painful tingling in one or both hands during the night, frequently painful enough to disturb sleep. Accompanying this is a feeling of uselessness in the fingers, which are sometimes described as feeling swollen, even though little or no swelling is apparent. As symptoms increase, tingling may develop during the day, commonly in the thumb, index, and ring fingers. A decreased ability and power to squeeze things may follow. In advanced cases, the thenar muscle at the base of the thumb atrophies, and strength is lost.

Many patients with CTS are unable to differentiate hot from cold by touch, and experience an apparent loss of strength in their fingers. They appear clumsy in that they have trouble performing simple tasks such as tying their shoes or picking up small objects.

Symptoms usually begin gradually without a specific injury. Numbness, tingling and pain in the hand are common. You may experience an electric-like shocking feeling. The thumb side of the hand is usually most involved. Symptoms at night are common and may awaken you from sleep. During the day symptoms frequently occur with holding a phone, reading or driving. Symptoms may occur at any time. Moving or shaking the hands often helps decrease symptoms. Sometimes strange feelings and pain will travel up the arm. Initially symptoms come and go, but over time they may become constant. A feeling of clumsiness or weakness can make delicate motions like buttoning buttons difficult and may cause you to drop things. If the condition is very severe, muscles in the palm may become visibly wasted.

Pain

• Episodic
• Temporal: Worse at night initially; Later during day also
• Location: Arm, forearm, wrist, hand & fingers
• Repetitive or sustained activity: Exacerbates pain
• Paresthesias
  • Palmar thumb, 2nd & 3rd fingers
  • Finger tips
• Weakness: After sensory
  • Abductor pollicis brevis (APB): Most common
  • Opponens pollicis

Diagnostic testing:

• Electrodiagnostic
  • Slow sensory conduction across transverse carpal ligament: Most sensitive
  • Later changes: Long motor latency; Low CMAP; Denervation in APB Systemic work-up: Thyroid; Blood sugar; Sed rate; CBC
• Electromyogram. Electromyography measures the tiny electrical discharges produced in muscles. A thin-needle electrode is inserted into the muscles your doctor wants to study. An instrument records the electrical activity in your muscle at rest and as you contract the muscle. This test can help determine if muscle damage has occurred.
• Nerve conduction study. In a variation of electromyography, two electrodes are taped to your skin. A small shock is passed through the median nerve to see if electrical impulses are slowed in the carpal tunnel.

These tests are also useful in checking for other conditions that might mimic carpal tunnel syndrome, such as a pinched nerve in your neck.

Risk Factors

The actual cause is unknown in most people. Carpal tunnel syndrome is more common in women. In women, the swelling that occurs during pregnancy may cause symptoms, but those will frequently go away after delivery. Carpal tunnel syndrome becomes more common as we grow older and seems to affect people with certain medical conditions such as diabetes, thyroid conditions and rheumatoid arthritis more frequently. Bending the wrist or moving the fingers brings muscles and tendons into action. For example, when a person bends a finger, the tendon moves about two inches. The tendons of the hand are encased in sheaths, or sleeves through which the tendons slide. The inner wall of the sheaths contains cells that produce a slippery fluid to lubricate the tendons. Lubrication is essential for the normal and smooth functioning of the tendons. With repetitive or excessive movement of the hand, the lubrication system may malfunction. It may not produce enough fluid or it may produce a fluid with poor lubricating qualities. Failure of the lubricating system creates friction between the tendon and its sheath causing inflammation and swelling of the tendon area. In turn, the swelling squeezes the median nerve in the wrist or carpal tunnel. Repeated episodes of inflammation cause fibrous tissue to form. The fibrous tissue thickens the tendon sheath, and hinders tendon movement.

What are the occupational factors of carpal tunnel syndrome? Carpal tunnel syndrome is particularly associated with certain tasks including:

• Repetitive hand motions awkward hand positions strong gripping mechanical stress on the palm
• Vibration

Non-occupational factors of carpal tunnel syndrome:Carpal tunnel syndrome is associated with several diseases and situations, including:

• Arthritis diabetes gout amyloidosis (infiltration of the liver, kidneys, spleen with a starch-like substance) hypothyroidism (subnormal activity of the thyroid gland) tumours of tendon sheaths wrist fractures and dislocations wrist cysts pregnancy use of oral contraceptives menopause
• Gynecological surgery

Treatment Options:

Symptoms can often be relieved without surgery. Treatment often begins with a brace or splint worn at night to keep the wrist in a natural position. Splints can also be worn during activities that aggravate symptoms. Simple medications such as Tylenol^® or Advil^® can help decrease pain. Changing patterns of hand use to avoid aggravating positions and activities may be helpful. A corticosteroid injection will often provide temporary relief, but symptoms may come back. If your carpal tunnel syndrome continues to bother you and you do not gain relief from non-surgical treatments, surgery can be effective in diminishing symptoms. Because carpal tunnel syndrome is not a dangerous problem, the decision whether to have surgery is based mostly on the severity of your symptoms.

• If your symptoms are severe and won't go away you may want to consider surgery. In more severe cases, surgery is considered sooner because other treatment options are less helpful.
• In very severe cases, surgery may be recommended to prevent irreversible damage.

Treatment Options: Surgical The strong roof of the carpal tunnel is cut during carpal tunnel surgery to increase the size of the tunnel and decrease pressure on the nerve. This is done through an incision in the palm or wrist. A small camera may be used to allow the surgery to be performed through a smaller incision. Risks of the surgery include bleeding, infection and nerve injury. Some pain, swelling and stiffness are expected, but severe problems are rare. After surgery, elevating the hand and moving the fingers helps minimize swelling and stiffness. Minor soreness in the palm is common for several months after surgery. Most patients have improvement following surgery, but recovery may be gradual. When carpal tunnel syndrome has been present longer and the nerve is more severely affected, recovery is slower and less complete.

Epidemiology

• Female: Male:: 3:1 Age peak: 40 to 60 years
• Dominant hand 1st; May become bilateral

NEW TREATMENT OPTION:

Certain medications that can be applied to the skin may provide immediate relief of the pain and numbness. Certain anti-convulsants and anti-inflammatories can be custom compounded into a new medication that can be applied DIRECTLY ONTO THE SKIN, and can minimize or eliminate the need for injections and oral medications.

CARPAL TUNNEL VARIANTS

Unfortunately, there are other, much smaller, delicate nerves in the wrist that can become damaged, and if these nerve problems are confused with Carpal Tunnel Syndrome (median nerve pathology) unnecessary surgery can occur, and the undiagnosed, underlying condition can actually worsen

Accurate diagnosis is essential if recovery is to be expexted. This requires the thoughtful use of blood tests, sensitive nerve testing by properly trained and skilled physicians, and a skillful physical examination.

Without a thorough understanding of a physical ailment, treatment is most likely to fail.

TAKE HOME MESSAGE: AVOID SURGERY, IF AT ALL POSSIBLE

David S. Klein, MD, FACA, FACPM, FACMIMS
Director, Pain Center of Orlando
www.suffernomore.com