Tayfun Altinok MD, Abstract Co-Author: Nothing to Disclose

Ozlem Baysal MD, Abstract Co-Author: Nothing to Disclose

Hakki Muammer Karakas MD, Presenter: Nothing to Disclose

Ahmet Kemal Firat MD, Abstract Co-Author: Nothing to Disclose

Dynamic carpal tunnel syndrome (CTS) is a subtype in which symptoms usually subside with rest but return when repetitive motions are resumed. Nerve conduction studies, performed at rest, is often elusive in this subgroup, and patients continue to have symptoms despite normal test results. In this study, the diagnostic value of provocative ultrasonographic (USG) examination in patients with dynamic CTS was evaluated.

Twenty wrists of 13 subjects (40.2 ± 10.2 yrs), diagnosed as dynamic CTS, and 10 normal subjects (35 ± 8.7 yrs) were investigated with USG measurements prior to and immediately after provocative exercises imitating work-related stresses. In addition to palmar displacement, nerve area at middle level and swelling ratio at pre- and post-exercise, two newely formed indices (Provocative nerve area ratio and provocative palmar displacement ratio) was calculated.

In the pre-exercise period, patients and controls were not significantly different regarding palmar displacement and swelling ratio. However, the difference was significant (p=0.035) for the nerve area at middle level. In the post-exercise period, all USG parameters were significantly different between patients and controls. Nerve area at middle level and swelling ratio produced higher significance (p<0.0001) than palmar displacement (p=0.015). There were significant differences between pre- and post-exercise values of all USG parameters in both normal and diseased subjects (p<0.0001 for all). The post-exercise swelling ratio had the highest sensitivity (95%) in diagnosing dynamic CTS with a cut-off value of 1.26. Provocative palmar displacement ratio had a high sensitivity (%80) and highest specificity (90%) for a cut-off of 1.28.

According to this study, provocative exercise increases sensitivity and specificity and contributes to the USG diagnosis of dynamic carpal tunnel syndrome. Post-exercise ultrasonographic measurements and calculations may be useful if routine USG examinations are normal. Therefore, provocative ultrasonographic evaluation should be recommended when the referring physician needs an additional confirmation after negative electrodiagnostic tests.

Altinok, T, Baysal, O, Karakas, H, Firat, A, Ultrasonographic Evaluation of the Carpal Tunnel after Provocative Maneuvers.  Radiological Society of North America 2004 Scientific Assembly and Annual Meeting, November 28 - December 3, 2004 ,Chicago IL. http://archive.rsna.org/2004/4413324.html