I will discuss what carpal tunnel syndrome is and what the examination of a carpal tunnel patient is like. At the end of the article is a description of a new method for releasing the carpal tunnel that doesn't involve an operating room or scalpel or endoscope.

The carpal tunnel is located on the palm side of the wrist.

It is called the carpal tunnel because the tendons, nerves, and blood vessels that enter the hand do so through a “tunnel” consisting of a floor formed by eight wrist bones with a roof composed of soft tissues. The major soft tissue structure is a ligament called the flexor retinaculum. This ligament stretches over the top of the tunnel.

The median nerve along with nine tendons that allow flexion (closing the hand) pass through the carpal tunnel. When the median nerve in the wrist is pinched, there is slowing of normal nerve impulses going through the nerve.

Since the median nerve carries fibers that provide the ability to feel and the ability to move the fingers, pressure or injury to the median nerve leads to symptoms such as numbness and tingling in the hand (primarily the thumb, index, and middle fingers... and possibly the middle part of the fourth finger) as well as hand weakness and loss of hand function.

Carpal tunnel syndrome may affect one or both hands. In addition to numbness, a person with CTS may experience pins and needle sensations or burning of the hand. Symptoms may radiate into the forearm and even up to the shoulder.

Symptoms often occur at night or early in the morning. Symptoms can also happen with activities such as driving, holding a book or repetitive motion activities involving the hands. In particular, actions requiring prolonged grasping or bending of the wrist can lead to CTS.

A person with CTS may note that fine motor activities like buttoning a shirt are difficult. Also, they may begin to drop things because of weakness in the hands.

One clue to CTS is that people who have it will often shake their hands to get relief. They also may complain of swelling in the fingers even though the fingers are not swollen.

Mild numbness and tingling are usually the first signs of CTS. CTS progresses to more persistent numbness and burning. In chronic cases, atrophy (loss of muscle) occurs at the base of the thumb in the palm. Once CTS progresses to severe muscle atrophy, it may not be reversible with treatment.

CTS can be associated with conditions such as pregnancy, obesity, thyroid disease, acromegaly (too much growth hormone), diabetes, arthritis, gout, and injuries. Repetitive motion involving the hand and wrist, particularly those that involve vibration, can aggravate the symptoms.

The diagnosis is not always easy because other conditions also cause symptoms of pain, swelling, numbness or weakness in the hands. For example, a pinched nerve in the neck or the forearm often can cause numbness and tingling in the hands. CTS may also coexist with a pinched nerve in the neck. This is called “double crush” syndrome.

Arthritis at the base of the thumb can cause pain and be mistaken for carpal tunnel syndrome.

Tendonitis, which is inflammation of the tendons, can lead to pain, swelling, and limited use of the hand or wrist and also be confused with CTS.

Obviously, these other conditions must be excluded before diagnosing carpal tunnel syndrome.

Most cases of CTS have no identifiable cause.

CTS is most common in middle aged or older people and women are three times more likely than men to get CTS.

Diagnosis of carpal tunnel syndrome is often made by extracting a careful history and doing an equally careful physical examination.

There may be diminished ability to feel pin prick or light touch. Tapping on the wrist with a reflex hammer may cause an electric shock-like sensation. This is referred to as a Tinel's sign. Flexing the wrist for a minute or so may reproduce the symptoms. This is called Phelan's sign.

Also, placing the palms of the hands together, then extending the wrists can also reproduce symptoms. This is called Palmer's prayer sign.

If CTS has been present for an extended period of time there may be muscle atrophy at the base of the thumb.

The diagnosis of carpal tunnel syndrome can be confirmed by electrical nerve conduction testing. Nerve conduction is measured by testing how fast an impulse is transmitted from the forearm to the palm of the hand along the median nerve. With CTS, the time it takes for an impulse to travel this distance is prolonged. The worse the CTS, the slower the rate of conduction.

Another electrical test is called the EMG or electromyography. A small needle is placed in the muscles supplied by the median nerve in the forearm and hand. Muscle cells carry an electrical charge. The type of electrical charge will change depending on whether the muscle is resting or contracting. Normal muscle has a typical electromyographic appearance. If the nerve supply to the muscle is compromised, as it is with carpal tunnel syndrome, then the electrical impulse pattern seen on EMG will exhibit abnormalities.

More recently, diagnostic ultrasound (DUS) and magnetic resonance imaging (MRI) have been used to help diagnose CTS and as well as other causes of hand and wrist symptoms. Using DUS or MRI, swelling of the median nerve and abnormalities of the carpal tunnel such as synovitis (inflammation of the lining of the wrist joint) or inflammation of the tendons can be identified.

Treatment of CTS depends on the causes and severity of the condition.

In cases of CTS where an underlying disease is causing the CTS, the disease needs to be treated. Examples include hypothyroidism (underactive thyroid gland) or rheumatoid arthritis.

For CTS, where the cause is not an underlying disease, then the treatment, at least initially, can be symptomatic. Non-steroidal anti-inflammatory drugs can be used to treat the pain. Splinting of the wrists, particularly at night can also reduce symptoms in mild CTS.

Injection of glucocorticoid (cortisone) into the carpal tunnel area can relieve symptoms for several weeks to months. If there is a good response- meaning at least 3 months or longer- the procedure can be repeated.

Conventional wisdom states that if the above measures fail, then surgery is required- either open or endoscopically (using a small telescope).

Unfortunately, surgery has the drawbacks of significant pain and extended recovery, sometimes taking 2 months or longer before full recovery.

However, there is another newer option that is much less invasive, less expensive, and requires a minimal amount of down time for the patient.

Using diagnostic ultrasound to identify the structures within the carpal tunnel, a small needle is inserted into the carpal tunnel using careful ultrasound guidance.

The needle, connected to a syringe, can be used to inject a small amount of fluid to free up the median nerve from nearby structures, then the needle is used to carefully perforate the flexor retinaculum while also using further fluid dissection to separate the fibers of the retinaculum. Once this has been done, the wrist is flexed and the weakened perforated retinaculum “pops” open.

All of this is accomplished under direct ultrasound visualization and guidance.

A small band aid is placed over the needle hole.

This method is well-tolerated and the patient may resume normal activities within a day.