Carpal tunnel syndrome (CTS) is a label commonly given to anyone experiencing pain, numbness and/or tingling in their hands. While carpal tunnel syndrome is one cause of hand symptoms it is not the only cause. Carpal tunnel syndrome occurs when the median nerve, which runs from a point near the shoulder through the forearm and into the hand, becomes compressed at the wrist. The median nerve controls sensations to the palm side of the thumb, first two fingers and half of the third finger (but not the little finger), as well as small muscles in the hand. The carpal tunnel is a narrow, rigid passageway of ligament and bones at the crease of the hand. It houses the median nerve and finger flexor tendons. Sometimes, thickening from irritated tendons or other swelling, narrows the tunnel compressing the median nerve. The result may be pain, weakness, or numbness in the hand and wrist, radiating into the fingers or up the arm. Although painful sensations may indicate other conditions, CTS is the most common and widely known of the nerve entrapments in which the body’s peripheral nerves are compressed or traumatized.
Symptoms usually start gradually, with frequent burning, tingling, or itching numbness in the palm of the hand and the fingers, especially the thumb and the index and middle fingers. Some carpal tunnel sufferers say their fingers feel useless and swollen, even though little or no swelling is visible. The symptoms often first appear in one or both hands during the night, since many people sleep in a fetal type position with their wrists and fingers flexed. A person with CTS may wake up feeling the need to “shake out” the hand or wrist. As symptoms worsen, tingling becomes present during the day. Decreased grip strength may make it difficult to form a fist, grasp small objects, or perform other fine movements. In chronic cases, the muscles at the base of the thumb may atrophy. Some people are unable to feel the difference between hot and cold by touch.
Carpal tunnel syndrome is often the result of a combination of factors that increase pressure on the median nerve in the carpal tunnel, rather than a problem with the nerve itself. Contributing factors include trauma or injury to the wrist that cause swelling, such as sprain or fracture; overactivity of the pituitary gland; hypothyroidism; rheumatoid arthritis; mechanical problems in the wrist joint; work stress; repeated use of vibrating hand tools; fluid retention during pregnancy or menopause; or the development of a cyst or tumor in the canal. In some cases no structural cause can be identified. In these cases the cause is entrapment at another site along the path of the median nerve through the arm. Numbness and tingling in all five fingers is not usually caused by a problem in the carpal tunnel and is more commonly associated with a disorder at or near the shoulder such as shoulder instability or thoracic outlet syndrome.
There is little clinical data to prove whether repetitive computer work can cause CTS. Repeated motions performed in the course of normal work or other daily activities can result in repetitive motion disorders such as bursitis and tendonitis. Women are three times more likely than men to develop CTS, perhaps because the carpal tunnel itself may be smaller in women than in men. The dominant hand is usually affected first and produces the most severe pain. Carpal tunnel syndrome usually occurs only in adults.
The risk of developing CTS is not confined to people in a single industry or job, but is especially common in those performing assembly line work – manufacturing, sewing, finishing, cleaning, and meat, poultry, or fish packing. In fact, carpal tunnel syndrome is three times more common among assemblers than among data-entry personnel. A 2001 study by the Mayo Clinic found heavy computer use (up to 7 hours a day) did not increase a person’s risk of developing carpal tunnel syndrome (National Institute of Neurological Disorders and Stroke (NINDS).
The non-surgical treatment of CTS involves manual therapy along the course of the median nerve from its formation in the upper arm to it’s path through the carpal tunnel at the wrist and flexibility training for the wrist and finger flexor muscles in the forearm. A 2007 research study documented the clinical efficacy of manual therapy for mild to moderate CTS. Strengthening of the wrist extensor, neck and upper back muscles for improved strength and posture also help to decrease tension along the path of the median nerve. Early in the treatment splints may be used at night to help reduce symptoms allowing for uninterrupted sleep. Once the symptoms reduce the brace should be abandoned as long term use of bracing increases the tightness that contributed to the problem in the first place.