WHAT IS IT?
Carpal tunnel syndrome (CTS) is the popular name for a complex of signs and symptoms that results from compression of the median nerve as it passes through the wrist in a narrow, rigid tunnel which is surrounded by the bones of the wrist, filled with tendons, and covered with a tight ligament called the transverse ligament. In the carpal tunnel, the nerve is accompanied by the nine tendons that flex the fingers and thumb. The most common cause of CTS is swelling of the membranes (tendon sheaths or bursae) that normally surround and lubricate the tendons as they glide in the tunnel. The signs and symptoms may be mild, moderate, or severe and usually worsen without treatment.
Figure 1: Cross Section of Left Hand - Palm Facing Up
WHO GETS IT?
The syndrome occurs more often in women, typically after age 30. A non-specific inflammatory swelling of tendon bursae (tenosynovitis) is the common cause. Tasks that require rapid, repetitive bending of the fingers, the use of vibratory tools, or a prolonged power grip, are known to hasten the onset of symptoms. Many diseases, some drugs, direct injury, and even pregnancy may increase the fluid (swelling) in the bursae enough to compress the median nerve in the rigid tunnel. The median nerve functions to provide sensation to a significant portion of the palm and fingers. In addition, it also is responsible for providing the motor control of some of the muscles of the palm and thumb.
SIGNS AND SYMPTOMS
The most frequent complaint is numbness and tingling of the palmar surface of any of the five digits, except for the little finger. A complaint about "dropping things" is frequent because of this numbness. Occasionally, an accompanying pain radiates into the forearm. Symptoms often first appear, or worsen, at night because of normal fluid shifting to the extremities, and normal wrist flexion during sleep. Prolonged or constant symptoms signal progressive of severe nerve compression, and thumb muscle weakness can follow. 'Locking' of the fingers is an associated complaint in 25% of cases of CTS because both can be caused by tenosynovitis.
An accurate medical history and the clinical examination will establish the diagnosis in most cases. Often, the symptoms can be duplicated or worsened by bending the wrist firmly palmward for 60 seconds (Phalen's test), and/or by tapping the front of the wrist over the nerve (Tinel's sign). The more uncomfortable (and expensive) electrodiagnostic test which measures nerve function are reserved for the evaluation of questionable diagnoses.
Patients with recent, mild, or intermittent symptoms may be treated successfully with anti-inflammatory drugs and night splints which prevent wrist flexion. However, most cases will recur if the cause of the nerve compression persists. Unless significant improvement is noted early in the treatment phase, non-operative treatment may not be successful.
Surgery is usually the treatment of choice for classic carpal tunnel syndrome. Typically, 80-90% of patients will have permanent relief of their symptoms following division of the wrist ligament (transverse carpal ligament) which covers the carpal tunnel. Release of scar around the median nerve and partial removal of the tendon bursae (sheath) is added in selected cases.
Figure 3: Swollen and Inflammed Median Nerve
Figure 4: Division Of The Transverse Ligament
By performing these procedures, it is possible to decrease the pressure on the nerve and to relieve the symptoms. Outpatient surgery, local anesthesia, and an incision limited to the proximal palm comprise the normal surgical approach today. Following surgery, while the complete relief of the nerve compression symptoms may be immediate, it often may take up to three months. Unfortunately, it is possible for the nerve to suffer permanent damage as the carpal tunnel syndrome develops. If this happens, then the likelihood of persistent symptoms, even after surgery, is greater. The annoying ache associated with an underlying tendon bursae disease, like the pains of arthritis, may linger on, without the threat of nerve dysfunction.
Carpal tunnel surgery may be performed either with the traditional open surgey or by using a telescope to visualize the nerve and transverse ligament. The surgery which is performed in this manner is called endoscopic surgery. The advantages of endoscopic surgery include: smaller incisions, faster recovery period, faster rehabiliation period and a decreased complication rate.
For more information on Endoscopic Carpal Tunnel Surgery: ENDOSCOPIC CARPAL TUNNEL RELEASE SURGERY (ECTR)
THIS MATERIAL DOES NOT CONSTITUTE MEDICAL ADVICE. IT IS INTENDED FOR INFORMATIONAL PURPOSES ONLY. PLEASE CONSULT A PHYSICIAN FOR SPECIFIC TREATMENT RECOMMENDATIONS.
THE CENTER FOR ORTHOPAEDICS AND SPORTS MEDICINE
1211 Johnson Ferry Rd
Marietta, GA 30068