Effects of continuous and pulsed radiofrequency applied for 120 and 240 seconds to rats' sciatic nerve.

Objectives: Radiofrequency (RF) has been used for many years for pain treatment. The effects of RF on nerves and the underlying mechanism of these effects are not clearly understood. The aim of this study is to show the effects of Pulsed (P-RF) and Continuous (C-RF) RF in light and electron microscopy, and to determine the differences between them.

Methods: In this study, a total of 60 Rattus norvegicus rats were used in 6 groups. No procedure was performed on the control group. In the Sham group, the electrodes were placed but no current was applied. P-RF for 120 seconds, P-RF for 240 seconds, C-RF for 120 seconds, and C-RF for 240 seconds at 42 °C were applied respectively to the other groups. Sections obtained from sciatic nerves were examined with light and electron microscopy.

Results: Examinations of the Sham, P120, and C120 groups were normal. In P240, some morphological changes were observed, but when all samples were examined, these abnormalities were evaluated as negligible. In C240, severe deformation of both myelinated and non-myelinated nerve fibers was observed under an electron and light microscope. Dramatic structural deformities in Schwann cells were observed.

Conclusion: P120, P240, and C120 treatments did not produce any deformities in the sciatic nerve. The application of C-RF for 240 seconds produced pathological alterations in the nerve structure.