Comparison of Inching Electrodiagnosis Method and Ultrasonographic Findings in the Determination of Median Nerve Entrapment Site in Carpal Tunnel Syndrome.

OBJECTIVE: The purpose of the study was to evaluate the diagnostic value of both inching method through the electrodiagnostic test and ultrasonographic assay in localizing the site of entrapment in patients with symptoms and signs of carpal tunnel syndrome. DESIGN: Thirty-two hands with confirmed carpal tunnel syndrome through electrodiagnostic test and 30 hands as control group were enrolled. For both groups, sensory and motor latencies by inching technique and cross-sectional area by ultrasonography were measured at the inching points. The statistical analysis was performed by SPSS software, and mean difference with 95% confidence interval was calculated. RESULTS: Mean of sensory peak latency with inching method and cross-sectional area by the ultrasonography was greater in case group compared with the control group (P < 0.05). We revealed a significant difference of antidromic sensory latency between two adjacent points belonging to the fifth and sixth segments. In orthodromic sensory and distal motor latency the sixth segment had statistically significant latency difference. Sixth and seventh points had the greatest cross-sectional area. Distal motor latency difference and cross-sectional area had the greatest sensitivity at the seventh point. CONCLUSIONS: In this study, we revealed the most sites of entrapment of the median nerve through carpal tunnel are 2- and 3-cm distal to the distal wrist crease.

Test-retest reliability of transcarpal sensory NCV method for diagnosis of carpal tunnel syndrome.

BACKGROUND: Carpal Tunnel Syndrome (CTS) is the most frequent entrapment neuropathy affecting the upper extremity. There are a variety of electrodiagnostic methods available for documenting median neuropathy in CTS. In some studies, determining the sensory NCV across the palm-wrist segment has been introduced as the most sensitive diagnostic procedure for CTS. The aim of this study was to investigate the test-retest reliability of transcarpal median sensory NCV method for the diagnosis of CTS. MATERIALS AND METHODS: Twenty-three patients with clinical symptoms of CTS were tested two times by two different practitioners in one session and again by the first practitioner after one week. Stimulation of the median nerve was performed in the wrist and palm, with a conduction distance maximum of 7 cm, reliabilities of median nerves sensory nerve action potential latencies with stimulation at wrist and palm (W-SNAP, P-SNAP) and its transcarpal NCV were assessed with intraclass correlation coefficient (ICC). RESULTS: Comparison of the obtained values, which were done by two practitioners in one session showed ICC of W-SNAP latency, P-SNAP latency and transcarpal NCV of 0.93, 0.88 and 0.87, respectively and values that were done by one practitioner in two sessions with one-week interval showed ICC of 0.60, 0.50 and 0.47, respectively. CONCLUSION: Our findings suggest excellent interpractitioner test-retest reliability of transcarpal median sensory NCV method for diagnosing CTS.