Magnetic resonance-guided focused ultrasound thalamotomy for treatment of essential tremor: A 2-year outcome study.

Background: Magnetic resonance-guided focused ultrasound is an emerging, minimally invasive thermoablation technique for medically refractory essential tremor. Beyond the initial year, data regarding efficacy and potential predictors of efficacy are still preliminary.
Objectives: The objective of this study was to assess the outcome at 2 years and the association between lesion volume and outcome 1 year after treatment.
Methods: We reviewed data from 37 patients who underwent unilateral magnetic resonance-guided focused ultrasound thalamotomy, with primary outcome being dominant tremor subscore of the Clinical Rating Scale for Tremor. We used multivariable linear regression to model initial lesion volume with 1-year outcome, adjusting for other clinically relevant variables.
Results: Although we detected a trend in loss of clinical benefit within the first year, the dominant tremor score at 2 years continued to be significantly improved (43.4%, 95% confidence interval 27.8%-59.0%) from baseline. Secondarily, initial lesion volume is significantly associated with 1-year outcome.
Conclusion: Our findings show that magnetic resonance-guided focused ultrasound thalamotomy results in sustained tremor reduction for medically refractory essential tremor even in the long term, and we highlight areas for improvement.
(© 2018 International Parkinson and Movement Disorder Society.)