The Effect of Straight Leg Raising on F-wave Parameters in Healthy Subjects and Patients with Lumbosacral Radiculopathy

Ha, Tae Hyun; Son, Suk; Kim, Jung Han; Lee, Hyun Suk

Abstract

OBJECTIVE
To determine if stretching the sciatic nerve in control and patients with lumbosacral radiculopathy significantly alters F-wave parameters. METHOD: We studied F-waves in the deep peroneal & posterior tibial nerves of 20 patients with unilateral lumbosacral radiculopathies and 22 controls. F-waves were recorded bilaterally in the neutral position and supine in 30o & 60o straight leg raising (SLR). F-wave parameters included minimal latency (F min), maximal latency (F max), mean latency (F mean), latency difference between F min and F max (chronodispersion), mean duration (F dur) and side to side difference in F min, F max, F mean and F dur.
RESULTS
In controls, the F-wave latency was found to be longer in supine with SLR than in neutral position. In patients with lumbosacral radiculopathy, significant differences of F max, F mean and F dur between sides during 30o SLR were noted in the deep peroneal nerves, but all parameters in the posterior tibial nerves during SLR were not changed.
CONCLUSION
In this study, we observed significant changes in F-wave latency in control during straight leg raising, but no significant changes in patients with lumbosacral radiculopathy. For the clinical application to lumbosacral radiculopathy, further study is needed.