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Updated: Feb 25, 2026
MRI-guided Focused Ultrasound Thalamotomy for Patients with Medically-refractory Essential Tremor
Published on: December 13, 2017
MRI-guided focused ultrasound thalamotomy in non-ET tremor syndromes
Alfonso Fasano1, Maheleth Llinas2, Renato P Munhoz2
1From the Morton and Gloria Shulman Movement Disorders Clinic and Edmond J. Safra Program in Parkinson's Disease (A.F., R.P.M.), Toronto Western Hospital-UHN, Division of Neurology, University of Toronto; Krembil Research Institute (A.F.); Division of Neurosurgery (M.L., A.M.L.), Department of Surgery, Krembil Neuroscience Centre, Toronto Western Hospital, University of Toronto; Joint Department of Medical Imaging (E.H., W.K.), University Health Network; and Department of Medical Imaging (W.K.), University of Toronto, Ontario, Canada. alfonso.fasano@uhn.ca.
Objective:
To report the 6-month single-blinded results of unilateral thalamotomy with MRI-guided focused ultrasound (MRgFUS) in patients with tremors other than essential tremor.
Methods:
Three patients with tremor due to Parkinson disease, 2 with dystonic tremor in the context of cervicobrachial dystonia and writer's cramp, and 1 with dystonia gene-associated tremor underwent MRgFUS targeting the ventro-intermedius nucleus (Vim) of the dominant hemisphere. The primary endpoint was the reduction of lateralized items of the Tremor Rating Scale of contralateral hemibody assessed by a blinded rater.
Results:
All patients achieved a statistically significant, immediate, and sustained improvement of the contralateral tremor score by 42.2%, 52.0%, 55.9%, and 52.9% at 1 week and 1, 3, and 6 months after the procedure, respectively. All patients experienced transient side effects and 2 patients experienced persistent side effects at the time of last evaluation: hemitongue numbness and hemiparesis with hemihypoesthesia.
Conclusions:
Vim MRgFUS is a promising, incision-free, but nevertheless invasive technique to effectively treat tremors other than essential tremor. Future studies on larger samples and longer follow-up will further define its effectiveness and safety.
Clinicaltrialsgov Identifier:
NCT02252380.
Classification Of Evidence:
This study provides Class IV evidence that for patients with tremor not caused by essential tremor, MRgFUS of the Vim improves the tremor of the contralateral hemibody at 6 months.
