Sympathetic skin response in fifth lumbar and first sacral radiculopathies

Skin temperature changes and sympathetic skin response (SSR) changes have previously been reported in lumbosacral radiculopathy patients (6). The SSR was studied in 14 normals and in 8 radiculopathy subjects with unilateral, EMG documented active radiculopathies to assess if the SSR becomes asymmetric when measured across appropriate dermatomes. The SSR was recorded in dermatomal patterns in both feet simultaneously with active electrodes on the plantar surface and reference electrodes on the dorsum. Four wave types were identified and normal values for latency of onset, latency of peak, and amplitude are presented with the normal left/right ratios presented. In all individual subjects the amplitudes of the SSR were extremely variable and asymmetric while latencies were less variable and more symmetric. There were no significant differences in symmetry between radiculopathy and normal subjects. When using this technique the SSR is not significantly altered in L5 and S1 radiculopathies.