Carpal Tunnel Syndrome – Holding the steering wheel tight during a car crash or falling down on your outstretched palms can cause injury to your wrist resulting in a carpal tunnel injury. Carpal Tunnel Syndrome is caused when fluid, bone, or stressed tendons press on the nerves within the carpal tunnel of the wrist. The result is generally wrist pain and numbness to the thumb and first two fingers.
The median nerve, which serves sensation in the palm of the hand, and movement of small muscles in the hand, is compressed at the wrist. The nerve is pinched between underlying ligaments and bones of the wrist and an overlying, tough ligament, the transverse carpel ligament. Symptoms may include tingling in the palm, and sometimes aching and burning. Characteristically the numbness awakes the patient at night, or is present with repetitive use of the hand. Pain may radiate up the arm toward the shoulder.
Often the symptoms are more gradual in onset. As the condition worsens, daytime paresthesias become common and often are aggravated by daily activities like driving, holding a book or the phone, and combing the hair. Weakness can be present. With long-standing or severe cases of carpal tunnel syndrome, thenar atrophy is frequently observed. Because of the motor and sensory disturbances, manual dexterity is diminished, and difficulty with daily activities (e.g. buttoning clothes, holding small objects) often is encountered. Pain and paresthesias also can occur proximally in the forearm, elbow, shoulder, and neck in up to one third of patients. Pain and paresthesias in the hand are not always isolated to median nerve distribution but can involve the ulnar aspect or the entire hand.
Diagnosis is made by the findings of three cardinal signs:
- Numbness in the distribution of the median nerve in the hand: palm, thumb, index, middle and lateral half of the ring finger.
- Tingling sensation radiating into the hand by tapping over the nerve.
- Reproduction of symptoms by marked wrist flexion for 30 to 60 seconds.
- Weakness in the small muscles of the hand controlled by the median nerve is found rarely.
- Sampling the electrical activity in the muscles and nerves (EMG) can aid in the diagnosis.
Conservative treatment of carpal tunnel syndrome can be done by immobilizing the wrist in a splint to minimize or prevent pressure on the nerves or the prescription of oral steroids. If that fails, patients are sometimes given anti-inflammatory drugs or injections of cortisone in the wrist to reduce the swelling.
When these efforts fail or when there is weakness, surgery, known as a carpal tunnel release, may be needed where the wrist is opened and the ligament is cut at the bottom of the wrist to relieve the pressure. However, only a small percentage of patients require surgery. The goal of operation is simply to divide the ligament, which decompresses the nerve. This division of the ligament can be done through a short incision with local anesthesia, in an outpatient surgery center. The operation only takes a few minutes and patients can return to normal activities afterwards, limited only by tenderness in the hand. Complications include a very low rate of infection and injury to the nerve. The vast majority of sufferers are relieved of their tingling, burning pain, but many have ongoing symptoms or can be made worse by complications.