Carpal Tunnel Syndrome

What is carpal tunnel syndrome?

Carpal tunnel syndrome (CTS) occurs when the median nerve, which runs from the forearm into the palm of the hand, becomes pressed or squeezed at the wrist. The carpal tunnel—a narrow, rigid passageway of ligament and bones at the base of the hand—houses the median nerve and the tendons that bend the fingers. The median nerve provides feeling to the palm side of the thumb and to the index, middle, and part of the ring fingers (although not the little finger). It also controls some small muscles at the base of the thumb.

Sometimes, thickening from the lining of irritated tendons or other swelling narrows the tunnel and compresses the median nerve. The result may be numbness, weakness, or sometimes pain in the hand and wrist (some people may feel pain in the forearm and arm). CTS is the most common and widely known of the entrapment neuropathies, in which one of the body’s peripheral nerves is pressed on or squeezed.

Who is at risk of developing carpal tunnel syndrome?

Women are three times more likely than men to develop carpal tunnel syndrome. People with diabetes or other metabolic disorders that directly affect the body’s nerves and make them more susceptible to compression are also at high risk. CTS usually occurs only in adults.

Workplace factors may contribute to existing pressure on or damage to the median nerve. The risk of developing CTS is not confined to people in a single industry or job, but may be more reported in those performing assembly line work such as manufacturing, sewing, finishing, cleaning, and meatpacking than it is among data entry personnel.

What are the causes of carpal tunnel syndrome?

Carpal tunnel syndrome is often the result of a combination of factors that increase pressure on the median nerve and tendons in the carpal tunnel, rather than a problem with the nerve itself. Contributing factors include trauma or injury to the wrist that cause swelling, such as sprain or fracture; an overactive pituitary gland; an underactive thyroid gland; and rheumatoid arthritis. Other factors that may contribute to the compression include mechanical problems in the wrist joint, repeated use of vibrating hand tools, fluid retention during pregnancy or menopause, or the development of a cyst or tumor in the canal. Often, no single cause can be identified.

How is carpal tunnel syndrome diagnosed?

Early diagnosis and treatment are important to avoid permanent damage to the median nerve.

  • The cornerstone of diagnoses is a physical exam coupled with a detailed and correlating history.

  • Electrodiagnostic tests may help confirm the diagnosis of CTSs. In a nerve conduction study, electrodes are placed on the hand and wrist. Small electric shocks are applied and the speed with which nerves transmit impulses is measured. In electromyography, a fine needle is inserted into a muscle; electrical activity viewed on a screen can determine the severity of damage to the median nerve.

How is carpal tunnel syndrome treated?

Treatments for carpal tunnel syndrome should begin as early as possible, under a doctor's direction.  Underlying causes such as diabetes or arthritis should be treated first.

Non-surgical treatments

  • Splinting.  Initial treatment is usually a splint worn at night.

  • Avoiding daytime activities that may provoke symptoms.  Some people with slight discomfort may wish to take frequent breaks from tasks, to rest the hand.  If the wrist is red, warm and swollen, applying cool packs can help.

  • Over-the-counter drugs.  In special circumstances, various medications can ease the pain and swelling associated with carpal tunnel syndrome. Nonsteroidal anti-inflammatory drugs (NSAIDs), such as aspirin, ibuprofen, and other nonprescription pain relievers, may provide some short-term relief from discomfort but haven’t been shown to treat CTS.

  • Prescription medicines.  Corticosteroids (such as prednisone) or the drug lidocaine can be injected directly into the wrist or taken by mouth (in the case of prednisone) to relieve pressure on the median nerve in people with mild or intermittent symptoms. (Caution: individuals with diabetes and those who may be predisposed to diabetes should note that prolonged use of corticosteroids can make it difficult to regulate insulin levels.)

  • Osteopathic manipulation has been shown in MRI and nerve conduction studies to improve median nerve function.

Surgery

Carpal tunnel release is one of the most common surgical procedures in the United States. Generally, surgery involves severing a ligament around the wrist to reduce pressure on the median nerve. The surgery can be done in the office, in an ambulatory surgery center or in a formal hospital operating room. However, it does not require an overnight hospital stay. While all carpal tunnel surgery involves cutting the ligament to relieve the pressure on the nerve, there are three different methods that are commonly done today. I only offer the two methods that I consider to be the safest.

  • Open release surgery, the traditional procedure used to correct carpal tunnel syndrome, consists of making an incision up to 1.5 to 5 cm in the wrist and then cutting the carpal ligament to enlarge the carpal tunnel.

  • Endoscopic surgery may allow somewhat faster functional recovery and less postoperative discomfort than traditional open release surgery but it may also have a higher risk of complications and the need for additional surgery.

  • Ultrasound guided surgery is performed using a special knife. A 4mm incision is made on the wrist. The main nerve and its tributaries are visualized under ultrasound. A mini knife is pushed under the skin and deployed under ultrasound visualization making sure not to cut any nerves.