Carpal tunnel syndrome (CTS) is one of the most common issues seen by hand surgeons. The median nerve runs through your forearm, wrist, and hand and supplies sensation to the thumb, index finger, long finger, and half of the ring finger. It also is responsible for innervating most muscles that control the thumb. At the level of the wrist, it runs through the "carpal canal" or "carpal tunnel" with all nine tendons that allow you to bend your fingers. If there is swelling in this area or otherwise pressure on the nerve, you might feel numbness, tingling, or even pain in your fingers, hand, and sometimes forearm.
Most CTS is "idiopathic," meaning that the cause is unknown. It can be associated with traumatic injuries like fractures (which cause narrowing of or swelling in the canal), "fluid retaining" states (such as pregnancy), hypothyroidism, rheumatoid arthritis, and diabetes.
The most common symptoms include pain, numbness, and tingling in the thumb, index, long, and ring fingers. Night symptoms are common because we often sleep with our wrists curled (or "flexed"), which compresses the nerve more. You might feel symptoms while driving, reading a newspaper, or holding a telephone, or during gripping activities. Some people actually start dropping objects or feeling clumsy with their hands. In severe cases, you could lose sensation or control of your thumb permanently.
Diagnosis is made by history and examination by your doctor. X-rays can determine if there are any bony reasons for the symptoms. A nerve conduction study (NCV) and/or electromyogram (EMG) might be performed to confirm the diagnosis and to check for other nerve problems.
Conservative treatment includes eliminating contributory factors, whether medical or behavioral. Activity modification can be helpful. Contrary to popular belief, the latest research suggests that people who type more actually have a lower incidence of carpal tunnel syndrome! Your positioning at your desk, however, can make a big difference. You want to make sure that your wrists are in "neutral" and that you are not leaning your palm (or forearm) on anything while you type.
Wearing wrist splints at night can help relieve night symptoms. Corticosteroid injections that decrease inflammation around the nerve can help your hand surgeon with the diagnosis or, in limited situations, can treat symptoms.
Surgical release of the carpal tunnel by cutting the ligament overlying the nerve and tendons in the palm of the hand enlarges the tunnel and decreases the pressure on the nerve. Soreness in the palm can last for weeks to a few months. Numbness and tingling can disappear quickly or slowly, but resolution of night symptoms usually occurs first. Strength in the hand and wrist can take a few months to return to normal. It can take a year to know how much symptom resolution you will get. Symptoms might not go away completely after surgery, especially in severe cases.
On a personal note, I often see patients who are afraid of having their carpal tunnel released because of horror stories they have heard. Although every surgery has its risks, carpal tunnel release usually is a very effective surgery with a relatively low complication rate. This actually is my hand during my own carpal tunnel release in 2008; my symptoms persisted despite splinting and a steroid injection, so I opted to have surgery. I am symptom-free and still operating (in both senses of the word)! You can see my story told on ABC News here...
Carpal tunnel syndrome is much more common in women than in men; we currently are studying the genetic and molecular basis for this with the help of the Ruth Jackson Orthopaedic Society-Zimmer Research Grant.