VIM thalamotomy with MRgFUS in Parkinson's disease: Efficacy, safety and technique

​Introduction: Ventral intermediate nucleus (VIM) thalamotomy using magnetic resonance-guided focused ultrasound (MRgFUS) has emerged as a minimally invasive alternative for refractory parkinsonian tremor. This study evaluates the efficacy, safety, and technical parameters of this intervention in patients with Parkinson's disease.Methods: A systematic review was conducted following PRISMA guidelines. Clinical studies evaluating VIM-targeted MRgFUS in Parkinson's disease with minimum one-month follow-up were included. Clinical variables (tremor reduction via CRST and MDS-UPDRS III, adverse events), technical parameters (maximum temperature, number of sonications, stereotactic coordinates), and technological evolution were analyzed.Results: Eleven studies reported 97 treated patients. Significant MDS-UPDRS III reductions were observed: 12.88 points at 1 month, 12.10 at 3 months, 14.85 at 6 months, and 20.65 at 12 months in medication "on" state. Adverse effects were mostly transient, including headache, dizziness, gait disturbances, and paresthesias, with spontaneous resolution in most cases. Technical parameters varied between studies, with average coordinates of 6.90-9.08 mm anterior to PC and 13.11-14.93 mm lateral from midline.Discussion: MRgFUS demonstrates sustained efficacy for parkinsonian tremor control with favorable safety profile compared to deep brain stimulation. Technological advances have optimized precision and reduced complications. Variability in technical parameters reflects technological evolution and the need for individualized targeting.