Can Pulsed Radiofrequency of the Occipital Nerves Cause Sedation? A New Perspective of Existing Knowledge

Background: Pulsed radiofrequency stimulation (PRF) of the greater and lesser occipital nerves (GON and LON) has neuromodulative and analgesic properties. Objectives: The aim of this study was to investigate whether the PRF of the occipital nerves can cause sedation. Methods: This is an observational case series study in Pain Management Unit of Attikon University Hospital. Patients suffering from primary headaches were scheduled for PRF of occipital nerves following a standardized protocol. The Bispectral Index device was applied and recorded every minute throughout the procedure. Results: 22 patients were studied. BIS values were lowered in all but three patients during GON stimulation, and in all patients during LON stimulation. Values of decline compared to baseline ranged between 0 - 23 (median 8.5) for GON and 1 - 27 (median 14) for LON, with LON decline being significantly lower. Conclusions: PRF at the occipital nerves led to mild sedation in all patients. Further studies are required to investigate this effect and clarify the exact mode of action of pulsed radiofrequency.