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Value of Testing in Carpal Tunnel Syndrome

This is the first study to compare two ways to predict symptom severity and function in patients with carpal tunnel syndrome (CTS). Ultrasound (also known as sonography) and electrophysiologic testing were compared. This type of information may help surgeons and patients decide when surgery is the recommended treatment of choice.

Ultrasound can be used to assess the structure of the median nerve. Pressure on the median nerve as it enters, passes through, and exits the carpal tunnel causes this syndrome. The carpal tunnel is an opening in the wrist formed by the arrangement of the bones and soft tissues. Ultrasound shows a cross-sectional area of the nerve. The amount of swelling present can be viewed this way.

The second type of testing was electrophysiologic measurements. The median nerve has both sensory (feeling) and motor (movement) function. This type of testing measures the presence and speed of nerve conduction along the nerve pathway.

Which is the better way to predict how severe the symptoms will be and functional status? The results of this study suggest electrophysiologic testing is more helpful than sonography. Testing the sensory nerve predicts symptom severity. Testing the motor nerve was a better predictor of function.

Flattening of the median nerve observed by ultrasound had some value. Swelling of the median nerve at the carpal tunnel entrance was present in cases of carpal tunnel syndrome of unknown cause. This type of CTS is called idiopathic.

The authors conclude that sonography may have some value in diagnosing idiopathic CTS. Electrophysiologic testing may be a better predictor of symptom severity and hand function. More studies are needed comparing CTS patients with mild to severe pain, numbness, tingling, and weakness of the wrist and hands.

References: Bayram Kaymak, MD, et al. A Comparison of the Benefits of Sonography and Electrophysiologic Measurements as Predictors of Symptom Severity and Funcitonal Status in Patients with Carpal Tunnel Syndrome. In Archives of Physical Medicine and Rehabilitation. April 2008. Vol. 89. No. 4. Pp. 743-748.

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