What is Carpal Tunnel Syndrome?

Written by: Randy Luo, MD, MBA 

Carpal tunnel syndrome is a condition that causes numbness, tingling, weakness, and other symptoms in the hand. It is the most common type of compressive neuropathy in the upper extremity. Incidence in the United States has been estimated at 1 to 3 cases per 1,000 subjects per year, with a prevalence of 50 cases per 1,000 subjects per year. ¹ It occurs when the median nerve, which runs from the forearm into the palm of the hand, becomes compressed or squeezed at the wrist within the carpal tunnel. 3 sides of the carpal tunnel are made up of bone and the top (roof) of the carpal tunnel is made up of a ligament. 9 tendons run through the carpal tunnel along with the median nerve, which gives sensation to the thumb, index finger, middle finger, and half of the ring finger.

What Causes Carpal Tunnel?

The exact cause of carpal tunnel syndrome is not always clear. It is generally caused by anything that may cause compression to the nerve. CTS is associated with several factors such as:

• Trauma or injury to the wrist, such as a fracture.
• Prolonged or excessive wrist flexion.
• Certain medical conditions such as diabetes, arthritis, or thyroid disorders.
• Pregnancy – increased swelling during pregnancy.

How is Carpal Tunnel Diagnosed?

Diagnosis of CTS is largely clinical. Dr. Graham developed 6 clinical criteria (called CTS-6) for the diagnosis of CTS which is widely used today. ² They include:

• Numbness and tingling in the median nerve distribution
• Nocturnal numbness
• Weakness and/or atrophy of the thenar musculature
• Tinel sign
• Phalen’s test
• Loss of 2-point discrimination

Additional testing such as electrodiagnostic testing (EMG/NCS) and ultrasound can be used but are not necessary for diagnosis of CTS. Electrodiagnosis tests have not shown any predictive value in determining the functional status or symptom severity in patient with carpal tunnel syndrome. ³ However, they are used to help diagnose potential other reasons for the clinical findings, such as compression of nerves in the spine and generalized neuropathy.

What are the Treatment Options for Carpal Tunnel?

Treatment options for carpal tunnel syndrome can vary depending on the severity of symptoms, underlying causes, and individual circumstances. Some common treatment options include:

Conservative Treatments:

• Wrist splinting: Wearing a splint to keep the wrist in a neutral (straight) position can help alleviate pressure on the median nerve. We typically ask the patients to wear the braces at night, but it may also help during activities such as driving.
• Rest and Activity Modification: Avoiding activities that worsen symptoms and taking regular breaks from repetitive tasks can help reduce strain on the wrist.
• Nonsteroidal anti-inflammatory drugs (NSAIDs): Over-the-counter medications such as ibuprofen or naproxen can help reduce pain and inflammation.
• Steroid injections: Corticosteroid injections into the carpal tunnel can help reduce inflammation and provide temporary relief from symptoms.

Surgery (carpal tunnel release):

For cases of carpal tunnel syndrome that do not respond to conservative treatments, surgery may be recommended. Surgery can either be performed open or endoscopically.

An open carpal tunnel release involves going through the skin and cutting the tight band (transverse carpal ligament) that makes up the roof of the carpal tunnel.

Endoscopic carpal tunnel release involves going through the wrist with a small 1-2cm incision and using a camera with a blade attached at the end to cut the same transverse carpal ligament.

Studies have shown equivalent results at a year or greater between the two types of surgeries. Endoscopic surgery has an advantage earlier in the recovery process in that patients usually return to work sooner given that the incision is smaller. Results from carpal tunnel releases are also very good, with reoperation rates quoted from 1-5%.⁴

In summary, carpal tunnel syndrome is a very common condition that affects many individuals. Treatment options usually begin with non-operative treatments. Surgery remains a great option in individuals whose symptoms are persistent or in those who have failed conservative therapy.

¹ American Academy of Orthopaedic Surgeons Work Group Panel Clinical guidelines on diagnosis of carpal tunnel syndrome. www.aaos.org/research/guidelines/CTS_guideline.pdf

² Graham B, Regehr G, Naglie G, Wright JG. Development and validation of diagnostic criteria for carpal tunnel syndrome. J Hand Surg 2006;31A:919–924

³ Chan L, Turner JA, Comstock BA, Levenson LM, Hollingworth W, Heagerty PJ, et al. The relationship between electrodiagnostic findings and patient symptoms and function in carpal tunnel syndrome. Arch Phys Med Rehabil 2007;88:19–24.

⁴ Bickel KD. Carpal Tunnel Syndrome. J Hand Surg 2010;35A:147–152.