Objective
The effect of the local steroid injection for the carpal tunnel syndrome (CTS) is well known, but there have been a few report of electrophysiologic evaluation for the effect of the local steroid injection. So this study was done to reveal the effect of local injection with triamcinolone acetonide (TA) into the carpal tunnel using the electrophysiologic changes and the improvement in symptoms.

Method
The triamcinolone acetonide (40 mg/ml) was injected to 43 patients (70 wrists) with the CTS diagnosed clinically and electrophysiologically. And the patients were reevaluated with the visual analogue scale and the electrophysiologic study every month. The mean duration of follow-up was 6 months, and the mean number of the injection was two times.

Results
The improvement of symptoms was noted in 90% of the cases, and most of the electrophysiologic parameters revealed significant improvement after the local injection of TA. The number of injection did not correlate with the visual analogue scale and the electrophysiologic parameters.

Conclusion
The local injection of TA into the carpal tunnel in the patients with CTS may be an effective therapeutic modality to improve the symptoms and the electrophysiologic parameters.