Optimizing VIM Targeting for Radiosurgery in Severe Tremor

Essential tremor is a common neurological disease, the most severe form of which combines postural and intention tremor, with significant physical, psychological and social repercussions. It is in these most severe forms that surgical lesioning of the ventro-intermediate nucleus of the thalamus (VIM) has been proposed. The VIM and its region of interest are almost impossible to identify directly on imaging (especially MRI), as it is part of the thalamus, which has the same intensity. To identify it, teams use average coordinates from stereotactic atlases (imprecise due to the high inter-individual variability of brain anatomy) or retrospective series of implanted patients. The hypothesis of the present trial is that the VIM-RS-LAT-1.0 algorithm developed by RebrAIn for radiosurgery will enable targeting that is at least as effective as conventional targeting. This is a single-center, controlled study, the primary endpoint of which will be assessed at one year, in a blinded, phase 3, comparative, non-inferiority, randomized study in two parallel groups of patients with severe tremor undergoing radiosurgery. In the control group, VIM will be targeted conventionally, and in the experimental group, VIM will be targeted by the RebrAIn algorithm (VIM-RS-LAT-1.0 model) of radiosurgery.