Carpal tunnel syndrome is characterized by numbness and tingling in your fingers and thumb. It can make it difficult to chop vegetables, button a shirt, and even navigate the touch screen on your cell phone. It can also affect your ability to work. Caused by compression of a major nerve in the wrist, carpal tunnel syndrome is the most common nerve problem in the United States.

While it is not clear why some people are prone to this nerve compression, there are a number of factors associated with it, including age, diabetes, renal failure, pregnancy, menopause, and overuse. It occurs more often in women than in men.

“Carpal tunnel treatment has progressed from surgery requiring an overnight stay in the hospital to a quick minimally invasive outpatient procedure under local anesthesia,” says J. Grant Thomson, MD, director of Yale Medicine Hand & Microsurgery. “While it is important to understand the risks and benefits of any procedure, patients should not be apprehensive about the surgical treatment of carpal tunnel syndrome. If treated early, patients can enjoy a return of normal hand function, improved sleep, and less pain.” 

The carpal tunnel is actually a space in the wrist, about an inch wide, that is surrounded by several structures. Bones make up three sides of it and a ligament runs across the top.

Running through the carpal tunnel are tendons that control the fingers, the thumb, and the median nerve, a major nerve that runs from the forearm to the palm. The median nerve provides sensation in the thumb, as well as in the index, middle, and ring fingers.

If the space is too small, the median nerve is compressed. This compressed nerve is what causes the symptoms of carpal tunnel syndrome.

People with carpal tunnel syndrome commonly complain about numbness and tingling in one or both hands (symptoms can start in the dominant or nondominant hand). Many people experience these symptoms in the thumb, index, middle, and/or half of the ring fingers, but many people feel that the entire hand is involved. Often the discomfort is first noticeable at night, sometimes becoming significant enough to disrupt sleep. Daytime symptoms may also arise, though sometimes not until months later.

It may affect other parts of the hand or arm as well. Some patients report numbness or tingling in the forearm or upper arm areas, and symptoms can radiate to the shoulder or neck. As the condition worsens, patients may experience weakness or clumsiness when using the hand, especially to grasp small objects. Some also develop profound weakness of the muscles at the base of the thumb. 

It used to be thought that computer or keyboard use caused carpal tunnel syndrome, but research has not supported that theory. It is most likely that an individual’s anatomy is the determining factor (a carpal tunnel that is too small for the contents), and that carpal tunnel symptoms were going to occur at some point in that individual’s lifetime regardless of their hand activities or associated diseases. Hand activities and associated diseases are certainly linked with worse symptoms, but in most cases, doctors are not able to determine the cause of carpal tunnel syndrome (it is called “idiopathic”). However, not knowing its cause should not affect the treatment strategy.

The disorder has been linked to the following conditions:

• Diabetes
• Excessive weight
• Gout
• Pregnancy (symptoms usually resolve after birth)
• Repetitive motion
• Rheumatoid arthritis
• Scleroderma
• Trauma
• Thyroid conditions
• Tumors 
• Renal failure

Your doctor will ask you to describe your symptoms, how they started, and how they have changed. The history of your disease is the most important factor in diagnosing carpal tunnel syndrome. A physical examination may help to confirm your diagnosis, and help determine the severity of the condition. Loss of sensation, constant numbness, weakness, and muscle wasting are indicators of severe nerve compression. Doctors may also recommend a test called a electrophysiologic or nerve conduction study to help determine the severity of carpal tunnel syndrome.

When carpal tunnel syndrome is diagnosed early, it can sometimes can be treated without surgery. Over-the-counter pain medications, wrist splints (worn at night), or simply changing how you work with your hands can provide significant relief. Corticosteroid injections, while commonly performed, do not provide long-term relief of symptoms, and the underlying nerve compression persists even if symptoms improve. Prolonged nerve compression can cause permanent nerve damage, and surgery should be performed in many cases to prevent permanent disability.

Carpal tunnel surgery is a common operation. It can be performed in one of two ways. The newest method (called endoscopic carpal tunnel surgery) involves making a small incision into the wrist crease and inserting an endoscope, a small television camera with a light, into the hand. 

This allows the surgeon to see (and divide) the ligament that lies over the carpal tunnel to increase the volume of the carpal tunnel, thus relieving the compression. This technique is associated with less pain in the first month after surgery, earlier recovery, and faster return to work.  

Another approach is traditional open surgery, using a larger incision in the palm. While this involves a longer immediate recovery time, it does not require any special equipment or expertise. The risks of complications and repeat surgery are the same regardless of the technique used to release the carpal tunnel.

Carpal tunnel syndrome surgery is performed under local or regional anesthesia in an outpatient setting, and patients usually go home the same day. However, long-term recovery from carpal tunnel surgery may take months, especially in severe cases of compression. While surgery is usually curative, a small group of people may have residual symptoms, either due to permanent nerve damage, scarring, or some other complication. 

The Yale Medicine Hand and Microsurgery Program is among the most comprehensive in our area for evaluation, diagnosis and treatment of both simple and complex conditions of the hand, wrist, and forearm. Yale Medicine was an early adopter of the endoscopic carpal tunnel release surgery described above, and surgery is performed by orthopedic and plastic surgery specialists.  

Treatment can be multidisciplinary, involving hand therapists both pre- and post-operatively in some cases. Often, neurologists, spine surgeons, and thoracic surgeons can be helpful in diagnosing and treating other nerve problems that can masquerade as carpal tunnel syndrome.

Our specialists work together to determine the best approach to diagnosing and treating even the most complex injuries, abnormalities, or diseases. Many patients who come to Yale Medicine find that treatment improves their hand function dramatically.