Carpal Tunnel Syndrome

How is carpal tunnel syndrome diagnosed?

CTS is diagnosed by carefully examining all the aspects of a patient that may be contributing to their condition.  This includes a past medical and surgical history (see: About Carpal Tunnel Syndrome), current complaints and symptoms, and noting any associated social or occupational activities. These are then combined with physical exam findings and additional imaging. On physical exam, Tinel's sign and Phalen's Maneuver are the two classic tests associated with the diagnosis of CTS.(see below) In addition, a physician may test your two-point descrimination (looking for sensory loss) and hand strength, especially muscles of the thumb, to look for signs of muscle atrophy (shrinkage). Exam of the neck and remainder of the arm, and a full exam of the contralateral side also helps rule out other potential causes of neurological symptoms.

Tinel's Sign - A clinical test performed to detect irritated nerves (the median nerve in this case) by lightly tapping over median nerve at the carpal tunnel ligament. (see below) A positive Tinel's sign elicits symptoms of CTS (burning, tingling, numbness or pain) over area innervated by the median nerve (thumb, index, middle, and ring fingers). Named after the French Neurologist, Jules Tinel (1879-1952).

Fig 3. Tinel's Sign is positive when tapping over the median nerve at the wrist reproduces symptoms of tingling or pain.

 

Phalen's Maneuver - This test, which again attempts to reproduce symptoms of CTS, is performed by having the patient hold a position with their arms held straight out infront of their body with elbows bent at 90 degree angles, with the wrists flexed at 90 degrees, and the back of the hands are pushed together to aid with forcible flexion of the wrist. Alternatively, the patient may hold their wrists flexed at 90 degree angles.(see below) This position is held for 30-60 seconds. A positive test result is one that reproduces symptoms of tingling or pain. A positive test result with Phalen's Maneuver has a higher sensitivity than a positive Tinel sign. Named after an American Orthopedist, George S. Phalen.

Fig 4. Phalen's Maneuver is positive when maintained forced flexion at the wrist results in reproducible symptoms of CTS.

 

Are there any additional tests?

Additional studies, may be obtained if the diagnosis of CTS is uncertain or to aid in the diagnosis of a medical condition associated with CTS, such as electrodiagnostic testing, radiographic imaging (X-ray, MRI, ultrasound), or blood tests. A simple X-ray can easily be performed to rule out fractures or arthritis.

If considering surgery, most surgeons will obtain electrodiagnostic testing to confirm the diagnosis of CTS. Electrodiagnostic testing, which includes electromyography (EMG) and nerve conduction studies (NCS), are usually performed by a neurologist. The EMG can determine muscle damage by using thin needle-like electrodes placed into the skin to measure muscular electrical activity. NCS are similar, and use electrodes placed directly on the skin to evaluate nerve conduction velocities through the carpal tunnel. A compromised nerve (such as the median nerve in CTS) will demonstrate decreased levels of functioning compared to the conduction of other normal nerves. Over time, as the median nerve is compressed, the myelin sheath (conducting material) of the nerve is damaged. As such, a certain amount of nerve damage must occur before being able to be detected by electrodiagnostic studies. Additionally, these tests can rule out other neurological conditions that can produce similar symptoms (pinched nerve in the neck). Patients with positive findings suggestive of CTS are generally offered surgical treatment.

It is important to note that a small percentage (10%) of patients with symptomatic CTS exhibit negative electrodiagnostic study results and may still benefit and be offered surgical intervention.

 

Continue to "Non-surgical Treatment Options"

Return to "Signs and Symptoms"

 

 

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Additional Information

Please see the provided Additional Links and Resources about Carpal Tunnel Syndrome for additional information and references.