By Michael G. Soojian, MD
Carpal tunnel syndrome (CTS) is a nerve compression syndrome that occurs as a result of pressure on the median nerve in the wrist. As the median nerve enters the hand, it passes through an enclosed space known as the carpal tunnel, along with the tendons that bend the fingers and thumb. If pressure builds up within the carpal tunnel, the median nerve gets irritated and inflamed causing feelings of tingling, burning, and numbness in the finger tips, specifically in the thumb, index finger, middle finger, and part of the ring finger. If CTS goes untreated long enough, it can irreversibly damage the median nerve, resulting in permanent numbness and weakness in the hand.
CTS is commonly associated with repetitive use of the hands, and may be associated with either leisure or work-related activities. CTS may also be related to an underlying medical condition such as diabetes, hypothyroidism, pregnancy, or an inflammatory condition like rheumatoid arthritis. It also can develop as a result of a wrist fracture or other types of trauma.
If patients are seen within a few months or less of initial symptoms, CTS can usually be treated without surgery. An important aspect of non-surgical treatment is figuring out the cause and then modifying activities appropriately. Ergonomic changes to computer workstations and wearing a brace to hold the wrist in a straight position can reduce pressure on the median nerve. Cortisone (a liquid anti-inflammatory) can be injected into the carpal tunnel as a means of decreasing nerve inflammation.
When non-operative treatment fails, or when patients have severe symptoms, surgery can be considered. A nerve test known as an EMG (or electromyography) with NCV (nerve conduction velocity) may be ordered. This test can serve to confirm the diagnosis of CTS and rule out other potential causes of nerve inflammation. Surgery is performed on an outpatient basis, usually with a combination of local anesthesia and a sedative injected through an IV. The goal of surgery is to cut through a ligament known as the transverse carpal ligament to convert the carpal tunnel from an enclosed space into an open space. This in turn releases pressure on the median nerve and allows it to recover and heal. Cutting through this ligament does not compromise wrist function and in some cases, patients experience an immediate dramatic relief in their numbness and tingling. In other cases, it can take weeks or months for the nerve to fully recover. Patients who are initially seen with constant numbness and weakness (signs of permanent nerve damage) usually do not regain normal nerve function, but often experience an improvement in symptoms.
In regards to both operative and non-operative treatment of CTS, the most important prognostic factors are the severity of the symptoms (numbness/ tingling) and the duration of time they have been present.