Sural and saphenous 14-cm antidromic sensory nerve conduction studies.

Objective: To create a large database of normal values for the sural and saphenous nerve conduction studies and to compare the results for the two nerves.

Design: Using a 14-cm antidromic technique, data were collected for onset latency, peak latency, onset-to-peak amplitude, peak-to-peak amplitude, area, duration, side-to-side variability, and between-nerve variability. A total of 230 subjects were included in the study.

Results: For the sural nerve, the upper limits of normal, defined as the 97th percentile of observed values, for onset latency, peak latency, and duration were 3.6, 4.5, and 2.1 msec, respectively. The comparable values for the saphenous nerve were 3.8, 4.4, and 1.9 msec, respectively. The lower limits of normal (third percentile) for sural onset-to-peak amplitude and peak-to-peak amplitude were 4 and 4 microV. The comparable values for the saphenous study were 2 and 1 microV. The upper limit of normal difference in onset latency between the two nerves was: saphenous 0.7 msec longer than sural or sural 0.3 msec longer than saphenous. The corresponding values for peak latency were: 0.6 and 0.5 msec.

Conclusion: Normal ranges are presented for a large database of subjects for the sural and saphenous nerve conduction studies.