Carpal tunnel syndrome: What to expect
Carpal tunnel syndrome is the most common form of peripheral nerve compression. It results from compromise of median nerve function caused by increased pressure in the carpal tunnel, a space at the wrist bounded by the bones of the carpus and the transverse carpal ligament. Increased pressure impairs the ability of the median nerve to conduct signals from the brain and spinal cord out to the fingers. It can result in numbness or weakness in the hand.
Who Gets Carpal Tunnel Syndrome?
Carpal tunnel syndrome is most commonly seen in patients in their 50s, 60s and 70s, but it can occur outside these age groups. It may be slightly more common in women than men. Any condition that increases pressure in the carpal tunnel or decreases the space available for the median nerve can cause symptoms, but most cases do not have a clear cause. It is unclear if heavy activity or repetitive use of the hands contributes to the development of the condition, but in many cases it does seem to aggravate symptoms.
Patients can present with a variety of symptoms, from transient numbness to irreversible muscle loss and hand weakness. Early recognition and appropriate treatment are essential in obtaining the best outcome and avoiding permanent deficits.
The median nerve supplies sensation to the thumb, index, middle and part of the ring finger. Patients may experience numbness, tingling, or pain in these areas, or they may have symptoms that seem to affect the whole hand. Often, symptoms are worse at night and worse with sustained postures or repetitive activities (e.g. driving, typing).
Symptoms may come and go based on hand position and activity, or in more severe cases they may be constant. The dominant hand is often the first side affected, although in about half of cases, both hands are affected at the same time.
If the condition becomes more advanced, patients may develop weakness in some of the small muscles in the hand. They may experience this weakness as clumsiness with buttons, change or other small objects or as difficulty with pinching and gripping. If left untreated for a prolonged period at this stage, transient weakness can progress to permanent muscle wasting and loss of function.
What to Expect When You See a Doctor
In evaluating for carpal tunnel syndrome, your physician will review your history and perform a physical examination. This exam will often include tests or maneuvers meant to provoke the symptoms of median nerve compression. For patients with numbness or pain beyond the median nerve distribution, examination of the neck and elbow can help evaluate for other sites of nerve compression or other pathology. In many cases, no further diagnostic studies are required, but if the clinical picture is unclear, additional testing such as nerve conduction studies may help to confirm the diagnosis.
For patients with mild or moderate symptoms, conservative treatment with splinting can reduce pressure on the median nerve and improve symptoms. Other proposed treatments include oral anti-inflammatory drugs, vitamin B-6 supplementation, activity modification and acupuncture, although these measures have less clinical evidence to support their efficacy.
If symptoms persist despite splinting, injection of steroids at the wrist can provide relief, with a good initial response in up to 70 percent of patients in some studies.
Unfortunately, steroid injection may not be a durable solution for carpal tunnel syndrome, with as many as 50 percent to 90 percent of patients experiencing relapse at longer term follow-up.
For patients who do not get relief with conservative treatment or for those who present with more severe symptoms (weakness or muscle atrophy), surgical decompression of the carpal tunnel is the treatment of choice. This procedure is typically done on an outpatient basis under local anesthesia. The hand is available for light activities immediately after surgery, and a return to heavier activities is often possible within two weeks.
Recurrence after surgical treatment is infrequent and is most often associated with initial misdiagnosis or inadequate decompression of the median nerve.
About the Author
Michael Potter, M.D. specializes in surgery of the hand, wrist, and elbow at Sentara Martha Jefferson Hospital in Charlottesville. He received his medical education at Duke University and did his specialty training in hand surgery at the Robert Chase Hand & Upper Extremity Center at Stanford University.