Carpal Tunnel Syndrome

WHAT IS CARPAL TUNNEL?

The carpal tunnel is a passageway in the wrist formed by the eight carpal (wrist) bones, which make up the floor and sides of the tunnel, and the transverse carpal ligament, a strong ligament stretching across the roof of the tunnel. Running through the carpal tunnel is the median nerve, a structure about the size of a pencil containing thousands of nerve fibers supplying sensation (feeling) to your thumb, index and middle fingers, and half of the ring finger. The median nerve lies directly beneath the transverse carpal ligament. Carpal tunnel syndrome is caused by increased pressure in the carpal tunnel resulting in compression of the median nerve. When the median nerve is pushed up against the ligament, blood flow to the nerve is restricted, causing a sensation often described as “pins and needles” to the fingers. In severe or chronic cases, numbness can be constant.

WHAT ARE THE CAUSES?

Carpal tunnel syndrome can be caused by a variety of problems. Certain medical conditions that may lead to compression of the median nerve include:

  • Inflammation or swelling about the tendons
  • Fluid retention
  • Wrist fractures and dislocations
  • Crushing injuries to the wrist
  • Rheumatoid/ degenerative arthritis
  • Diabetes
  • Hypothyroidism
  • Pregnancy

There is considerable debate as to whether specific work activities may lead to carpal tunnel syndrome. Certain occupational activities which involve repeated flexing of the fingers or wrist, or prolonged use of vibrating tools may contribute to the development of carpal tunnel syndrome. Determining whether or not carpal tunnel syndrome is a work-related condition can be very difficult. Each case must be considered individually and must be based on documentation of specific work-related activities which may contribute to this condition. Non-work related activities of daily living and leisure may also provoke symptoms of carpal tunnel syndrome. Lawn mowing, long distance driving, or hobbies such as knitting or wood carving may elicit symptoms of carpal tunnel syndrome.

WHAT ARE THE SIGNS AND SYMPTOMS?

Numbness, burning, or tingling of one or more fingers (excluding the little finger) is the most common symptom of carpal tunnel syndrome. This numbness can happen at any time: often these symptoms occur at night and may awaken the individual from sleep. Partial relief can sometimes by gained by shaking, massaging, or elevating the hands. At times, the numbness may extend up the arm, into the elbow, and as far up as the shoulder and neck.

A decrease in sensation may result in weakness of the affected hand. Patients may find themselves dropping objects and less capable of performing tasks requiring gripping or pinching strength. Some of the muscles in the thumb are controlled by the median nerve. With advanced carpal tunnel, these muscles may begin to waste away, giving a flattened appearance to the palm when compared to the other hand.

HOW IS IT TREATED?

Conservative treatment of patients with mild symptoms usually involves avoidance of activities that may provoke further symptoms. Your physician may prescribe a splint to be worn to restrict movement of the wrist. Depending of the severity of the condition, the splint may be worn during the day and or night. The length of time the splint is needed varies, but can be for approximately 4-6 weeks. In some instances, a cortisone injection may be administered into the carpal tunnel to decrease swelling. This may greatly reduce the patient’s discomfort.

When conservative treatment does not achieve the desired results, or in cases involving more severe symptoms, surgery may be recommended.

 Surgery involves releasing the ligament forming the roof of the tunnel. This relieves the pressure of the median nerve. With the blood flow to the median nerve restored, the symptoms of burning and tingling are usually relieved soon after surgery. Patients can expect soreness from the incision for 2-6 weeks.  Improvement in strength and sensation depend on the extent of the nerve damage prior to treatment.