Background MR-guided focused ultrasound (MRgFUS) thalamotomy has been shown to be a safe and effective treatment for essential tremor (ET).
Objective To investigate the effects of MRgFUS in patients with ET with an emphasis on ipsilateral-hand and axial tremor subscores.
Methods Tremor scores and adverse effects of 100 patients treated between 2012 and 2018 were assessed at 1 week, 3, 12, and 24 months. A subgroup analysis of ipsilateral-hand tremor responders (defined as patients with ≥30% improvement at any time point) and non-responders was performed. Correlations and predictive factors for improvement were analysed. Weighted probabilistic maps of improvement were generated.
Results Significant improvement in axial, contralateral-hand and total tremor scores was observed at all study visits from baseline (p<0.0001). There was no significant improvement in ipsilateral subscores. A subset of patients (n=20) exhibited group-level ipsilateral-hand improvement that remained significant through all follow-ups (p<0.001). Multivariate regression analysis revealed that higher baseline scores predict better improvement in ipsilateral-hand and axial tremor. Probabilistic maps demonstrated that the lesion hotspot for axial improvement was situated more medially than that for contralateral improvement.
Conclusion MRgFUS significantly improved axial, contralateral-hand and total tremor scores. In a subset of patients, a consistent group-level treatment effect was observed for ipsilateral-hand tremor. While ipsilateral improvement seemed to be less directly related to lesion location, a spatial relationship between lesion location and axial and contralateral improvement was observed that proved consistent with the somatotopic organisation of the ventral intermediate nucleus.
- STEREOTAXIC SURGERY
- FUNCTIONAL NEUROLOGICAL DISORDER
- MOVEMENT DISORDERS
Data availability statement
Data are available upon reasonable request. Anonymised data will be shared by request from any qualified investigator.
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KY and CS are joint first authors.
Contributors KY: drafting/revising the manuscript, figures and tables; statistical analysis; imaging analysis; and interpretation of data. CS: drafting/revising the manuscript and tables and interpretation of data. GJBE, AB, AL: revising the manuscript, imaging analysis and interpretation of data. JG: revising the manuscript, statistical analysis and interpretation of data. SEJ: imaging analysis. LB, DG, RG, SXL: acquisition of data. AZ, AV: revising the manuscript. MA, GD, MC, KH, NS, MLS: acquisition of data. AML: revising the manuscript, study concept or design, interpretation of data, accepts responsibility for conduct of research and will give final approval, acquisition of data, study supervision. AF: revising the manuscript, study concept or design, statistical analysis, interpretation of data, accepts responsibility for conduct of research, will give final approval, acquisition of data and study supervision, and is responsible for the overall content as the guarantor.
Competing interests KY, GJBE, AB, JG, AML, LB, DG, RG, SXL, AZ, AV, MA, GD, MC, KH, NS and MLS report no disclosures relevant to the manuscript. CS has been receiving fellowship grants from Michael and AD Foundation and Turkish Neurosurgical Society. SEJ receives salary from General Electric. AML is scientific director for Functional Neuromodulation and a consultant to Medtronic, Abbott, Boston Scientific, Insightec and Focused Ultrasound Foundation. AF reports the following: consultancies from Abbvie, Medtronic, Boston Scientific, Sunovion, Chiesi Farmaceutici, UCB and Ipsen; membership in advisory boards of Abbvie, Boston Scientific and Ipsen; receiving honoraria from Abbvie, Medtronic, Boston Scientific, Sunovion, Chiesi farmaceutici, UCB and Ipsen; receiving grants from University of Toronto, Weston foundation, Abbvie, Medtronic and Boston Scientific.
Provenance and peer review Not commissioned; externally peer reviewed.
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