Magnetic resonance-guided focused ultrasound pallidotomy in Parkinson's disease: a systematic review of efficacy and safety

Background: Magnetic resonance-guided focused ultrasound (MRgFUS) has emerged as a minimally invasive alternative for treating motor complications in advanced Parkinson's disease (PD). This systematic review evaluates the efficacy, safety, and technical parameters of globus pallidus internus (GPi) pallidotomy using MRgFUS in PD patients.Methods: A systematic review was conducted following PRISMA guidelines, searching PubMed/MEDLINE, Embase, Scopus and Web of Science, through February 2024. Clinical studies evaluating MRgFUS-guided GPi pallidotomy in PD patients were included, with minimum follow-up of one month and at least 3 patients per study.Results: Four studies including 101 patients were analyzed. Eisenberg et al. reported 59% improvement in Unified Dyskinesia Rating Scale (UdysRS) scores at 3 months (p<0.0001), maintained at 12 months (43% improvement). Jung et al. demonstrated 52.7% UdysRS reduction at 6 months and 42.7% at 12 months. MDS-UPDRS III scores improved significantly in "off" medication state, with Eisenberg et al. showing 44.5% improvement at 3 months and 45.2% at 12 months. Krishna et al. found 69% response rate in active treatment group versus 32% in controls (p=0.003). Adverse events were generally mild and transitory, including transient dysarthria, fine motor deficits, and headache during sonication.Conclusions: MRgFUS GPi pallidotomy demonstrates significant and sustained efficacy in treating levodopa-induced dyskinesias and motor fluctuations in PD patients, with an acceptable safety profile. Technical parameters vary across studies, emphasizing the need for individualized treatment protocols. Further research is warranted to optimize patient selection and procedural standardization. Keywords: Parkinson's disease, MRgFUS, globus pallidus internus, pallidotomy, dyskinesias