PHALEN’S TEST

What’s Phalen’s Test?

Phalen’s test refers to a diagnostic test used in the detection of carpal tunnel syndrome. The carpal tunnel refers to a narrow passageway found on the palm side of the hand which serves as the entrance to the palm for several tendons and the median nerve. Carpal tunnel syndrome results from any injury
that significantly reduces the size of the carpal tunnel or more commonly, increases the size of some of the structures that pass through it. Consequently, this size reduction compresses the median nerve which bears the bulk of the sensitivity in the tunnel. The pain that accompanies carpal tunnel syndrome often intensifies at night and daily activities including driving and typing may increase the symptoms.

Common symptoms of carpal tunnel syndrome include:
1- Numbness in the hand or thumb
2- Pain that starts at the wrist and extends into the arm
3- Persistent pain and tingling of hand and fingers

Technique for Phalen’s Test

The conduction of Phalen’s test usually occurs in the sitting or standing position. The patient places a passively flexed arm on a table, allowing the wrists to fall into maximum flexion. The neurosurgeon then asks the patient to push the dorsal hand surface together, holding this position for 30-60 seconds. As the wrists flex, the pressure in the carpal tunnel increases, and the median nerve, in turn, compresses. The compressed median nerve then produces characteristic symptoms such as numbness or tingling sensations over the fingers or pain in the wrist and fingers.

Reverse Phalen’s Test

Conduction of Reverse Phalen’s test begins when the neurosurgeon instructs the patient to maintain full wrist and finger extension for 2 minutes. This test remarkably increases pressure in the carpal tunnel within 10 seconds compared to 20-30 seconds for the standard Phalen’s test. A study to compare the changes in pressure between Phalen’s and Reverse Phalen’s tests noted that the average pressure change for Phalen’s test resulted to 4 mmHg in two minutes versus 34 mmHg at one minute and 42 mmHg at two minutes for the Reverse Phalen’s test. The Reverse Phalen’s test significantly changes the pressure within the carpal tunnel and results in a higher intracarpal canal pressure as compared to a standard Phalen’s test. This possibly makes it more useful as a provocative diagnosis measure.

Positive Phalen’s Test

A positive Phalen’s test results when the characteristic symptoms of carpal tunnel syndrome reappear during the course of the test. The test will elicit the same symptoms as that experienced with carpal tunnel syndrome namely paresthesia- burning, tingling, or numb sensation over the thumb, middle, index, and ring fingers.

Negative Phalen’s Test

A negative Phalen’s test results when the patient feels no pain or any other characteristic symptom of carpal tunnel syndrome, even when the motion is maintained for 3 minutes or longer.

Accuracy

The diagnostic accuracy of a provocative test depends on the sensitivity and specificity of the test. Phalen’s test presents sensitivity ranging from 51% to 91% and a specificity that ranges from 33% to 88%. Phalen’s test presents a large range of sensitivity and specificity and due to the wide range, Phalen’s provocative test should only turn useful in an adjunctive manner to diagnose carpal tunnel syndrome.

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References

Magee DJ. 2002, Orthopedic Physical Assessment, 4th edition, Philadelphia: Saunders
Urbano, FL. Tinel’s sign and Phalen's Maneuver: Physical Signs of Carpal Tunnel Syndrome. Hospital
Physician 2000; Jul,39-44. http://www.turner-white.com/pdf/hp_jul00_tinel.pdf (accessed 20Dec2009)
Werner R, Bir C, Armstrong T (1994). "Reverse Phalen’s maneuver as an aid in diagnosing carpal tunnel syndrome. Archives of Physical Medicine and Rehabilitation.
Phalen GS. The carpal tunnel syndrome. Seventeen years experience in diagnosis and treatment of six hundred fifty – four hands. J Bone Joint Surg 1996;48:211-28