Radiosurgery has recently emerged as a suitable treatment of pharmacologically resistant idiopathic trigeminal neuralgia. Results and complications of this treatment are related to parameters of the dosimetry, i.e. the dose and the target. We found that the irradiation dose delivered to the brainstem, the distance between the target and the brainstem, and the occurrence of facial numbness after radiosurgery are related to a better pain outcome.