Hand numbness and pain is a frequent problem. Many people attribute those symptoms to carpal tunnel syndrome. Carpal tunnel is a specific entity and is only one of many causes of hand pain and numbness. Carpal tunnel syndrome occurs when the median nerve is irritated within the carpal tunnel. The carpal tunnel is a canal in the wrist. The floor and walls of this canal are comprised of bone. A ligament (the deep transverse ligament) forms the roof of this canal. The tendons that bend the fingers (finger flexor tendons) also course through the carpal tunnel along with the median nerve.
The median nerve may be irritated or injured by pressure within the carpal tunnel, by external pressure or vibration transmitted to the nerve, and by traction stress (pulling) on the nerve.
Classical carpal tunnel syndrome symptoms include pain, numbness, and tingling involving the thumb-half of the palm, the thumb, index, long fingers, and the half of the ring finger facing the long finger. The small finger side of the hand is supplied by another nerve (the ulnar nerve). Pain may radiate up the forearm, elbow, upper arm, and even to the shoulder. Pain and numbness is often worse at night making sleep difficult. People often wake up with hand pain and numbness and describe having to hang their hand off the edge of the bed or shaking their hand to relieve their symptoms. More advanced carpal tunnel syndrome may be associated with grip weakness to the point that people drop objects from their hand. The muscles at the base of the thumb may shrink (thenar atrophy) due to dysfunction of the recurrent motor branch of the median nerve.
Some simple physical exam tests can be done to help determine if a person has carpal tunnel syndrome. Tinel's sign is performed by tapping a finger tip over the carpal tunnel. The carpal tunnel compression test is performed by placing finger pressure over the carpal tunnel with the wrist slightly flexed (bent). Phalen's sign is performed by flexing the wrist downwards. All of these tests are considered positive for carpal tunnel syndrome if they result in precipitation or aggravation of pain and numbness radiating into the thumb, index, long, and/or ring fingers.
More specialized tests to confirm the diagnosis of carpal tunnel syndrome include the use of a carpal tunnel steroid injection in which steroid and a local anesthetic (xylocaine) is injected into the carpal tunnel. Symptom relief after a carpal tunnel steroid injection supports a diagnosis of carpal tunnel syndrome.
Nerve conduction tests are a diagnostic test where an electrical stimulus is administered to the forearm above the carpal tunnel. An electrode is placed around a finger of the hand, usually the index finger. The nerve conduction instrument measures the time it takes for the electrical stimulus to travel from the stimulating electrode in the forearm to the recording electrode attached to the finger. The electrical stimulus travels very fast through a normal nerve. However, the electrical stimulus travels more slowly though injured segments of nerve tissue. The magnitude and location of the conduction slowing allows determination of the severity and site of nerve injury.
Initial treatment for carpal tunnel syndrome includes the use of a wrist splint that serves to limit wrist bending and also holds the wrist in a relatively straight position minimizing pressure on the median nerve. Wrist splints can be worn during daytime activity and also at night while sleeping. Activity modification may be necessary if there is some activity that is causing or aggravating the carpal tunnel syndrome. Medical problems such as diabetes and hypothyroidism may be associated with carpal tunnel syndrome and treatment of these conditions may help relieve carpal tunnel syndrome symptoms. Nonsteroidal anti-inflammatory medications (NSAIDs) are often prescribed. Carpal tunnel steroid injections are often effective.
Carpal tunnel release surgery can be done when nonsurgical measures are unsuccessful. Surgery involves releasing the transverse carpal ligament thereby taking pressure off of the median nerve. Surgery takes about twenty minutes and is done on an outpatient basis. A person should not use their hand for strenuous activities for six weeks after surgery. The results of surgery are good if the carpal tunnel syndrome is treated early in its course. There may be residual symptoms when treatment is delayed since some degree of permanent nerve damage may have occurred by the time of surgery. Surgery is beneficial even in these delayed cases since decompression of the median nerve helps to prevent additional pressure related nerve injury and it also allows the nerve a chance to heal.
Surgery eliminates intrinsic pressure (ie, pressure inside the hand) on the median nerve caused by the overlying ligament since the ligament is cut at surgery. But, surgery does not prevent injury to the median nerve from extrinsic (ie, pressure on the outside of the hand) pressure caused by activities such as gripping. QwiTM Nerve Protection Gloves can help to prevent extrinsic pressure and vibration injury to the median nerve.
Carpal tunnel syndrome is a common, treatable problem. Successful treatment depends upon prompt recognition of the diagnosis and treatment early in the course of the condition in order to avoid permanent median nerve damage.
