If you suffer from pins and needles or numbness affecting the thumb, index or middle fingers you are probably suffering from carpal tunnel syndrome. It affects about 5% of the population and women are affected more often than men. The first time it happens is usually at night when you wake up with an uncomfortable tingly feeling in your fingers.
The carpal tunnel is a narrow passage in the wrist through which the tendons that move the fingers and a major nerve (median nerve) passes through. The nerve innervates a few small muscles in the hand and is also responsible for sensation of the thumb, index, middle and half of the ring finger. The tunnel is made up of wrist bones on one side bridged by a tough ligament for the roof on the other. When the space in the tunnel occupied by the tendons and nerve is reduced from any cause, the nerve gets squeezed and carpal tunnel syndrome results.
Incidence: It often affects people who indulge in continuous repetitive work involving the hands and wrist. Among people involved with manual labour, it affects those who use a pneumatic drill or a jack hammer at work. Among office workers, secretaries, clerks and software engineers, it may affect those who constantly use a key board. It can also occur after an injury to the wrist. Symptoms may also appear when excessive fluid collects in the body as during pregnancy or when you suffer from diabetes.
Symptoms: When mild, symptoms are noticed during the night. People usually wake up with numbness and a feeling of pins and needles in the fingers. Symptoms may ease when you shake your hand vigorously or let your hand hang by the side of the bed. With increased pressure on the nerve symptoms become constant and often noticed during the daytime while at work. When it progresses further the small muscles that move the thumb become weak and appear wasted. Pain may sometimes radiate in to the forearm.
Diagnosing Carpal Tunnel Syndrome: It is usually diagnosed by clinical examination. Tapping the nerve at the wrist may produce pins and needles shooting to the fingers. Similarly bending the wrist to its extreme position can cause numbness in any of the fingers supplied by the nerve.
Electromyogram and nerve conduction study are tests that will confirm increased pressure on the nerve. They are simple tests done in the outpatient clinic.
Treatment: Treatment can vary from simple measures when symptoms are mild to surgery when they are severe affecting ones daily activities. If possible, the person affected must be advised to rest the hand and wrist and avoid any activity causing repetitive strain on the wrist.
Wrist Splint: The splint usually worn at night, will support the wrist. It will prevent the wrist from bending that normally increases the pressure on the nerve. You may be able to purchase it from a chemist or an online supplier. The splint is useful when symptoms are mild.
Steroid Injection: Injecting steroid in to the carpal tunnel may reduce the inflammation and thereby the swelling relieving the symptom
s. Care must be taken not to inject the drug in to the nerve or the tendons.
Oral anti-inflammatory medication only rarely helps.
Surgery: Surgery is recommended when other treatments have failed.
Surgery is usually done as an outpatient procedure under a local anaesthetic. The procedure is fairly simple where the tough ligament forming the roof of the tunnel is divided completely. The nerve is protected when the ligament is divided and the surgeon will make sure that the pressure on the nerve is completely relieved.
Following surgery the wound will be protected for about 10 days. It may take about a month to six weeks before any strenuous activity can be undertaken using the operated hand.
Complications of Carpal Tunnel Syndrome: When the pressure on the nerve is severe and unrelieved for a long time, it will result in permanent numbness of the fingers with poorly functioning thumb muscles. This indicates permanent damage of the nerve. It is therefore vital that you do not delay treatment if the fingers are continuously numb.
K. Badrinath, FRCS (Edin), MSc Orthopaedics (Lond)