Carpal Tunnel Syndrome
Introduction
Carpal Tunnel Syndrome is more common in women and people between the ages of 30 and 60 years old. It is the most common nerve entrapment syndrome and affects up to 10% of the population. Individuals with Carpal Tunnel Syndrome may feel numbness, pain, and a “tingly” sensation in their fingers, wrists, and arms. They may have difficulty performing grasping and gripping activities because of discomfort or weakness.
Anatomy
The Median Nerve supplies the sense of feeling to our thumb, index finger, middle finger, and half of the ring finger. It also sends messages to the Thenar Muscles that move the thumb. We use the Thenar Muscles when we position our thumb to grasp and hold objects. If the Median Nerve is compressed in the Carpal Tunnel, it will send faulty messages as it travels into the hand and fingers.
Causes
Usually, the cause of Carpal Tunnel Syndrome is unknown. However, there are several circumstances that can create pressure on the Median Nerve.
Pressure may develop from prolonged wrist positioning that compromises the position of the median nerve. The median nerve may become irritated when our wrists are bent downward or flexed for long periods of time. Irritation may occur when the wrist is flexed and the hand is turned towards the side of the little finger. We position our hands like this when we hold on to the handlebars on a bicycle or the handles used to push a wheelchair or a lawnmower. These hand positions are also used when we grasp carpentry tools, such as the handle on a hammer or a paint roller. Other factors that appear to contribute to the development of Carpal Tunnel Syndrome include cold temperature and repetitive, forceful, vibratory, and fast movements, such as those used in the meat packing industry.
Some medical conditions, such as diabetes and thyroid disease, are associated with Carpal Tunnel Syndrome. Rheumatoid arthritis, joint dislocation, and fractures can cause the space in the tunnel to narrow. Some women develop Carpal Tunnel Syndrome because of swelling from fluid retention caused by hormonal changes. This may occur during pregnancy, premenstrual syndrome, or menopause.
Symptoms
Diagnosis
Your doctor may ask you to perform a couple of simple tests to determine if there is pressure on the Median Nerve. For the Phalen’s Test, you will firmly flex your wrist for 60 seconds. The test is positive if you feel numbness, tingling, or weakness. To test for the Tinel’s Sign, your doctor will tap on the Median Nerve at the wrist. The test is positive if you feel tingling or numbness in the distribution of the median nerve. Lab tests may be ordered if your doctor suspects a medical condition that is associated with Carpal Tunnel Syndrome. Your doctor may take an X-ray to identify arthritis or fractures.
In some cases, physicians use nerve conduction studies to measure how well the Median Nerve works and to help specify the site of compression. Physicians commonly use a test called a Nerve Conduction Velocity (NCV) test. During the study, a nerve is stimulated in one place and the amount of time it takes for the message or impulse to travel to a second place is measured. Your doctor will place sticky patches with electrodes on your skin that covers the Median Nerve. The NCV may feel uncomfortable, but only during the time that the test is conducted.
An Electromyography (EMG) test is often done at the same time as the NCV test. An EMG measures the impulses in the muscles to identify poor nerve input. Healthy muscles need impulses to perform movements. Your doctor will place fine needles through your skin and into the muscles that the Median Nerve controls. Your doctor will be able to determine the amount of impulses conducted when you contract your muscles. The EMG may be uncomfortable and your muscles may remain a bit sore following the test.
Surgery
The standard surgery for Carpal Tunnel Syndrome is called an Open Release. The surgeon will use a local or regional anesthetic to numb the hand area. For this procedure, the surgeon makes a two to three inch opening along the palm. This allows the surgeon access to the Transverse Carpal Ligament, the roof of the Carpal Tunnel. The surgeon makes an incision in the Transverse Carpal Ligament to open the tunnel and make it larger. By doing so, pressure is taken off of the median nerve. The surgery time for an Open Release is short, only about fifteen minutes.
Another surgical option is called Endoscopic Carpal Tunnel Release. This type of surgery is done using an endoscope placed in a small incision. An endoscope is small device with a light and a lens that allows the surgeon to view the Carpal Tunnel without disturbing the nearby tissues. It may be used in conjunction with a camera or video system.
Endoscopic Carpal Tunnel Release most often uses a local or regional anesthetic to numb the wrist and hand area. In some cases, individuals are sedated for the surgery. The surgeon makes a small opening below the crease of the wrist and inserts the endoscope to view the Carpal Tunnel. Some surgeons make a second incision in the palm of the hand. Guided by the endoscope, the surgeon places a tube called a cannula along the side of the Median Nerve. A special surgical instrument is inserted through the cannula that makes an incision in the Transverse Carpal Ligament. This surgery also opens the Carpal Tunnel and makes it larger to take pressure off of the Median Nerve. Because Endoscopic Carpal Tunnel Release spares some of the tissue in the palm, individuals may heal faster and experience less discomfort.
Treatment
Recovery
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This information is intended for educational and informational purposes only. It should not be used in place of an individual consultation or examination or replace the advice of your health care professional and should not be relied upon to determine diagnosis or course of treatment.
The iHealthSpot patient education library was written collaboratively by the iHealthSpot editorial team which includes Senior Medical Authors Dr. Mary Car-Blanchard, OTD/OTR/L and Valerie K. Clark, and the following editorial advisors: Steve Meadows, MD, Ernie F. Soto, DDS, Ronald J. Glatzer, MD, Jonathan Rosenberg, MD, Christopher M. Nolte, MD, David Applebaum, MD, Jonathan M. Tarrash, MD, and Paula Soto, RN/BSN. This content complies with the HONcode standard for trustworthy health information. The library commenced development on September 1, 2005 with the latest update/addition on February 16, 2022. For information on iHealthSpot’s other services including medical website design, visit www.iHealthSpot.com.