Influence of tibial trancutaneous repetitive electrical nerve stimulation on neurogenic claudication and F-wave in lumbar spinal stenosis.

OBJECTIVES To determine whether repetitive tibial nerve stimulation (RTNS) affects neurogenic claudication and F-wave conduction in lumbar spinal stenosis. DESIGN An intervention study: before/after trial. SUBJECTS Data for 12 central lumbar spinal stenosis patients were compared with 13 age- and sex-matched healthy volunteers. METHODS A conditioning RTNS at the ankle, 0.3-ms duration square-wave pulses with an intensity 20% higher than the motor threshold, was applied at a rate of 5/s for 5 min. We assessed the effects of RTNS on the claudication distance at which the lumbar spinal stenosis patients can no longer continue walking due to increasing leg symptoms, and on tibial F-wave measurements. RESULTS A comparison between mean pre-RTNS and post-RTNS revealed a significant difference in claudication distance (66 m (standard deviation (SD) 19) vs 133 m (SD 37); p = 0.003), mean F-wave minimal latency (48.3 ms (SD 1.7) vs 44.8 ms (SD 1.0); p = 0.007) and mean F-wave conduction velocity (53.3 m/s (SD 2.0) vs 55.5 m/s (SD 1.9); p = 0.009) in the lumbar spinal stenosis group, but not in the control group. CONCLUSION RTNS has beneficial effects on neurogenic claudication and F-wave conduction in central lumbar spinal stenosis patients. This phenomenon may have practical value in providing a new therapeutic modality for lumbar spinal stenosis.