Carpal tunnel syndrome(CTS) is the most frequent entrapment neuropathy which can be diagnosed by electrophysiological methods. But in some patients with mild symptoms, it is difficult to diagnose with the conventional methods. To evaluate whether
the
new method is useful for diagnosis of CTS wit mild symptoms, sensory nerve conduction studies(SNCS) were performed at the first digital branch(DB) and the palmar cutaneous branch(PCB) of the median nerve in 65 patients with suspicious CTS and in
57
controls. The difference of the SNCS latency between DB nerve and PCB nerve(DB-PCB SNCS) were compared between patients and controls.
The results were as follows: the mean latency, amplitude, and nerve conduction velocity of the difference of DB-PCB in controls were 0.11±0.17msec, 20.75±15.55μv and 3.57±4.21m/sec respectively, and those CTS were 0.92±0.75msec,
11.09±22.01μv and
14.99±8.22m/sec respectively. The paients were graded into 3 groups by clinical symptoms, and the difference of DB-PCB SNCS were conducted significantly by the clinical severity (in ANOVA test). The diagnostic rate of CTS were 53%(70 of 132
wrists) by
the conventional method but that was 75.8%(100 of 132 wrists) by the DB-PCB SNCS method. Symptomatic CTS which was normal SNCS by the conventional method were diagnosed 50.8% (33 of 65 wrists) as CTS by the DB-PCB SNCS method. And patients with
grade I
were diagnosed as CTS in 12% (6 of 50 wrists) by the conventional method, but in 60% (30 of 50 wrists) by the DB-PCB SNCS method.
Above results indicate that the new method is simple and useful adjunctive method in the early diagnosis of CTS with mild symptoms.
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