A reverse Phalen test (Prayer test) is also used to evaluate the median nerve compression in the case of Carpal tunnel syndrome.
The patient is asked to keep both hands with the wrists in complete extension for 60 seconds (wrist and finger extension).
This position increases the pressure in the carpal tunnel. Paresthesia in the region supplied by the median nerve is a sign of Carpal tunnel syndrome.
The reverse Phalen test is less reliable than the Phalen test.
Wrist flexion Test
Wrist flexion test is a similar maneuver to phalen test, it’s used to diagnosis the Carpal tunnel syndrome as well.
The patient is positioned in sitting with the elbow fully extended, the forearm in supination, and the wrist flexed to 60 degrees. The clinician applies an even constant pressure over the median nerve at the carpal tunnel using the thumb.
A positive test for CTS is the reproduction of symptoms along the median nerve distribution within 30 seconds.
Tetro and colleagues found this test to have a sensitivity of 86 percent and a specificity of 95 percent.
Phalen’s Test Accuracy
The original Phalen test has demonstrated a a high sensitivity and a moderate specificity making it moderately acceptable for use in clinical practice:1
Specificity: 47 %
While in Reverse Phalen Test, a study by de Krom and colleagues 2 found the test to have a sensitivity of 41 % and a specificity of 55 %.
In another study, Werner and colleagues 3 showed that Reverse Phalen Test results in a significantly higher intracarpal canal hydrostatic pressure as compared to a traditional Phalen or a modified Phalen maneuver and may add to the sensitivity of conventional screening methods.
In one study to assess the usefulness of the Phalen test and the Hoffmann Tinel sign in the diagnosis of Carpal tunnel syndrome, the sensitivity and specificity of the Phalen test was respectively 855 and 89%, and for the tinel test, 67 and 68%.
Some studies have varied this test to be performed by the patient with wrist in complete flexion and elbow extended, bilateral wrist flexion with the posterior aspect of the hand pressing against one another, or passive wrist flexion by the clinician.
Carpal tunnel syndrome
Carpal tunnel syndrome is a cause of chronic wrist pain and functional impairment of the hand. It results from an ischemic compression of the median nerve at the wrist as it passes through the carpal tunnel.
Compression of the nerve in the carpal tunnel is compounded by an increase in synovial fluid pressure and tendon tension, which decreases the available volume.
The compression of the median nerve may result from a wide variety of factors that compromise the tunnel space such as:
fluid retention, which occurs during pregnancy, Infection and conditions such as renal dysfunction.
In addition, several disease conditions, such as gout or pseudogout, acromegaly, or amyotrophy can also decrease the tunnel size.
About half of the cases of Carpal tunnel syndrome are related to repetitive and cumulative trauma in the workplace.
Carpal tunnel syndrome is the most common compression neuropathy, with a prevalence of 9.2 % in women and 0.6 % in men.
The initial characteristic features of Carpal tunnel syndrome include intermittent pain and paresthesias in the median nerve distribution of the hand which progressively become more persistent as the condition progresses.
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