Provocative tests in different stages of carpal tunnel syndrome

The frequency of positive results of four conventional provocative tests (Phalen sign, Tinel sign, wrist extension and pressure provocation test) was evaluated in 179 patients with clinical and electrophysiological findings consistent with idiopathic carpal tunnel syndrome (CTS), 147 control subjects and 39 patients with polyneuropathy. The diagnostic accuracy was evaluated for each test alone and in combination and the sensitivity correlated with the clinical and electrophysiological severity of CTS. For comparison of the CTS group with the control group, none of the tests reached sufficient diagnostic accuracy. The same was found for comparison of the CTS group with the polyneuropathy group, the Tinel sign being the least accurate. The combination of signs was not found to be more useful than single signs. The sensitivity of all signs was much less in severe clinical stages of CTS, especially for tests that increase the intra-carpal canal pressure. Traditional provocative tests, such as those tested here, have limited or no value for distinguishing patients with and without CTS, one reason being that their sensitivity depends largely on the clinical and electrophysiological severity of CTS. This correlation may also explain the contradictory results in the literature.