Carpal Tunnel Syndrome
What is Carpal Tunnel Syndrome?
The carpal tunnel is a fibrous passageway in the wrist that contains the median nerve and the nine flexor tendons to the thumb and fingers. The median nerve is one of three major nerves of the hand. It is responsible for sensation to the thumb, index, middle, and thumb side of the ring finger. In addition, the median nerve controls the muscles of the thumb to allow it to turn and touch each fingertip. In Carpal Tunnel Syndrome, the fibrous passageway for the median nerve can become narrower in the wrist and lead to compression of the nerve.
What are the symptoms of Carpal Tunnel Syndrome?
With continued compression of the median nerve, patients can develop numbness and tingling of one or more of the areas supplied by the nerve (thumb, index, middle, and ring). Some patients experience dull, aching pain in the hand during nighttime or awaken in the morning with numbness in the thumb and fingers. In long-standing or severe circumstances, the nerve compression can lead to weakness or paralysis of the muscles moving the thumb and loss of muscle mass on the thumb side of the palm.
What causes Carpal Tunnel Syndrome?
Risk factors for Carpal Tunnel Syndrome include repetitive wrist work, obesity, pregnancy, diabetes, and autoimmune disease. The common factor in these conditions is that they all lead to increased swelling in the fibrous passageway and decreased space for the median nerve. In this situation, the nerve remains in continuity but is its outer lining and blood supply can be damaged by the pressure caused by this tight passageway. In response, scar tissue replaces the natural outer insulation of the nerve, called myelin. Myelin is critical in speeding the transmission of electrical signals to the muscle to cause contractions or from the skin to the brain to produce feeling. With scar replacing myelin, electrical signals cannot easily travel across the nerve.
How is Carpal Tunnel Syndrome diagnosed?
Carpal Tunnel Syndrome can generally be diagnosed by the history of symptoms and by physical exam looking for signs of thumb and finger numbness, loss of muscle mass in the palm, or nerve inflammation (Phalen’s, Tinel’s, Durkan’s, and scratch collapse tests). In the Phalen’s test, the wrist is maximally bent for up to 60 seconds and the patient is asked if there are any symptoms of thumb or finger pain, numbness, or tingling. Using the Tinel’s test, the skin over the carpal tunnel is tapped and the patient is asked if there are any signs of tingling or electrical shocks traveling to the thumb, index, or middle finger. In the Durkan’s test, the carpal tunnel is compressed for up to 30 seconds and the patient is asked if there are any symptoms of thumb or finger pain, numbness, or tingling. For the scratch collapse test, the patient performs resisted shoulder external rotation exercises. The test is considered positive if the wrist is lightly scratched and the patient momentarily collapses while performing resisted shoulder external rotation. In situations where the diagnosis is unclear, a nerve conduction and muscle study can be ordered to obtain more information on the health of the median nerve and its muscles.
What are the treatments for Carpal Tunnel Syndrome?
Treatment of Carpal Tunnel Syndrome begins with wrist splinting to minimize repetitive wrist motion, non-steroidal anti-inflammatory drugs to reduce the swelling and inflammation, diet and exercise in obese patients, and strict glucose control in diabetics. If these measures fail to eliminate the patient’s persistent pain, numbness, and/or muscle weakness, a carpal tunnel release is recommended. In this procedure, a nerve decompression / neurolysis is performed of the median nerve through a small incision in the palm. The goal is to provide space for the nerve and its blood supply, giving it a chance to regenerate. Doing so in a timely fashion should lead to speedier electrical signals and return of movement, feeling, and function.
What happens after surgery for Carpal Tunnel Syndrome?
Open carpal tunnel release generally takes less than one-hour and can be performed under general or wide awake local anesthesia. After the completion of surgery, the wrist and palm are wrapped in a soft, bulky dressing. Following a 1-2-hour recovery period, patients are discharged home the same day on Tylenol, Motrin, and sometimes on a short course of narcotics. Elevation and finger motion are recommended to push out the swelling and prevent joint stiffness. Light activity is encouraged when comfortable for the patient. One week after surgery, patients may take off their bandages and get the incision wet. Lifting is limited to 5 pounds for 6 weeks. Six weeks after surgery, patients may resume full activity. With mild and/or intermittent symptoms, relief of numbness, tingling, and pain is often immediate. With long-standing or severe cases, relief of symptoms and return of muscle function may be more gradual and over the course of many months.