ORCID

Abstract

BackgroundUnilateral magnetic resonance guided focused ultrasound (MRgFUS) thalamotomy reduces tremor in essential tremor, yet disability often persists on the untreated side. The added benefit and safety of a staged contralateral lesion remain uncertain.ObjectiveThe aim was to evaluate the efficacy and safety of staged bilateral MRgFUS thalamotomy for essential tremor.MethodsWe searched MEDLINE, EMBASE, Web of Science, Cochrane CENTRAL, Scopus, ClinicalTrials.gov, and World Health Organization International Clinical Trials Registry Platform from inception to April 12, 2026 (PROSPERO CRD420251027624). Eligible studies were staged bilateral MRgFUS with Clinical Rating Scale for Tremor outcomes and adverse events, and at least 3 months of follow up. Two reviewers extracted data per Preferred Reporting Items for Systematic Reviews and Meta-Analyses. The primary outcome was the standardized mean difference (SMD) in tremor severity from pre- to post-second procedure. Safety outcomes were pooled 3-month adverse event proportions using random effects. Risk of bias was assessed with Newcastle-Ottawa Scale and Risk of Bias in Non-randomized Studies of Interventions; certainty was graded with Grading of Recommendations Assessment, Development, and Evaluation.ResultsNine studies were included in the systematic review, of which seven cohorts (n = 149) were included in the meta-analysis. The pooled SMD was −1.91 (95% confidence intervals, −2.19 to −1.63; I2 = 0%), indicating consistent, large-magnitude tremor reduction across all seven cohorts. Three-month adverse events included sensory changes (28.8%), gait disturbance (27.5%), dysarthria (22.0%), taste changes (21.7%), dysphagia (18.4%), and ataxia (11.3%). All studies were single-arm and non-randomized with moderate to serious risk of bias, and certainty was very low.ConclusionsStaged bilateral MRgFUS yielded clinically meaningful tremor reduction with predominantly mild adverse events at 3 months. Given very low certainty, findings are hypothesis-generating and support-controlled studies with blinded assessment and longer follow-up.

Publication Date

2026-08-09

Publication Title

Movement Disorders Clinical Practice

Acceptance Date

2026-06-17

Deposit Date

2026-08-21

Funding

No specific funding was received for this work. N.N.S. is supported by the National Institute for Health and Care Research (NIHR; award 306,286). E.F. is funded by a UK Research and Innovation (UKRI) Future Leaders Fellowship (FLF) (MR/Y034368/1), a Biotechnology and Biological Sciences Research Council (BBSRC) grant (BB/Y001494/1), a Neuromod+ grant (EP/W035057/1), and an Advanced Research and Invention Agency (ARIA) grant (SCNI-PR01-P15). The authors declare that there are no conflicts of interest relevant to this work. The authors declare no competing interests.

Keywords

bilateral, essential tremor, high intensity focused ultrasound, meta-analysis, neuromodulation, thalamotomy

Creative Commons License

Creative Commons Attribution 4.0 International License
This work is licensed under a Creative Commons Attribution 4.0 International License.

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