Background and objectives: Radiofrequency facet denervation procedures are widely used for the treatment of chronic low-back pain. Currently, both temperature-controlled and voltage-controlled techniques are used. In this combined in vivo and in vitro study, the electrophysiologic consequences and the effects on lesion size of these techniques were determined.
Methods: Thirty-three patients were randomly assigned to receive a lumbar radiofrequency facet denervation by using either temperature-controlled (80 degrees C, 60 seconds) or voltage-controlled (20 V, 60 s) mode. Electrophysiologic parameters in both groups during radiofrequency lesioning were registered. Observed differences between electrodes were quantified and interpreted, using lesion-size data from egg-white experiments.
Results: Seventeen patients in the temperature group were treated with a total of 55 radiofrequency lesions, all considered technically adequate. In the voltage-controlled group, 16 patients received 63 lesions. Of these, 44 (69.8%) procedures were found to be technically inadequate. Voltage-controlled radiofrequency lesioning resulted in uncontrollable fluctuations of temperature, with resultant uncontrollable variations in lesion size. Temperature-controlled mode created reproducible lesion sizes.
Conclusions: There is no consistent relation between voltage and the temperature obtained during radiofrequency lumbar facet denervation. Temperature-controlled radiofrequency lesioning is preferred to create reproducible lesion sizes.