Staged bilateral MRgFUS thalamotomy associated with tremor reduction in medication-refractory essential tremor

BACKGROUND: Staged bilateral Magnetic Resonance-guided Focused Ultrasound (MRgFUS) thalamotomy is an incisionless option for medication-refractory essential tremor (ET). While the efficacy and safety of unilateral MRgFUS are established, evidence for bilateral treatment remains limited. OBJECTIVE: To evaluate the efficacy and safety of staged bilateral MRgFUS in a prospective single-centre observational cohort and to perform a systematic review and meta-analysis of the literature. METHODS: Consecutive ET patients undergoing second-side MRgFUS were prospectively assessed. The primary efficacy endpoint was the longitudinal change in Clinical Rating Scale for Tremor (CRST) A + B scores for the treated hand after FUS2, while safety was evaluated by collecting and grading adverse events (AEs). A systematic review identified published bilateral MRgFUS series; efficacy data were meta-analysed, while AEs were reported descriptively. RESULTS: Fifteen patients (60% men; mean age 74.1 ± 8.9 years) underwent FUS2 28.9 ± 22.5 months after first-side treatment. At the 12-month evaluation, CRST A + B decreased from 21.0 to 8.8 (-58%), CRST C from 7.3 to 1.9 (-74.2%), and QUEST from 30.5 to 9.5 (-68.7%). Head and voice tremor were reduced by 73.8% and 40.3%, respectively. AEs were predominantly mild (95.2%) and transient (88%). Cognition at 1 year was globally preserved, with a selective decline in verbal episodic memory. Meta-analysis confirmed significant improvement in tremor severity. CONCLUSION: Staged bilateral MRgFUS thalamotomy was associated with sustained tremor reduction, including midline tremor, functional improvement and acceptability, with a manageable safety profile. Overall, consistent with literature, these findings support its potential role as a therapeutic option in selected ET patients.