F waves are late responses resulting from antidromic activation of motor neurons occuring when the axon is stimulated supramaximally. Because of their long pathway from stimulation site to motor neuron, many studies are reported for the usefulness of F wave in radiculopathy. The sensitivity of F waves in radiculopathy is varying from 18% to 65%. Our purpose was to evaluate the usefulness of F wave in radiculopathy by simulating radiculopathies in rabbits.

With properly anesthesized rabbit, we exposed sciatic nerve at ischial tuberosity level and traced up the nerve trunk to reach the spinal canal level. Then we dissected one of two nerve roots and measured F waves.

The parameters which showed significant difference after root dissection were latency and conduction velocity in upper root dissection and amplitude in lower root dissection. But the normal control levels of such parameters are so wide that the changes of such parameters after root dissection are not useful for evaluation of radiculopathy.

Therfore, our conclusion was that measuring F wave was not so useful for electrodiagnosis of radiculopathy.