Positive Two-Year Outcomes for Treatment of Essential Tremor With Focused Ultrasound
Patients with medically refractory essential tremor treated with magnetic resonance-guided focused ultrasound (MRgFUS) thalamotomy had a mean 43.4% reduction in their scores on the Clinical Rating Scale for Tremor (CRST) (CI 95%, 27.8%-59%).
Thermoablation with MRgFUS is an emerging and minimally invasive technique with only preliminary data for efficacy and predictors of efficacy after the first year available. This study adds to the knowledge base for outcomes of the technique by providing data for 37 patients, 17 of whom have had reduced CRST scores for 2 years posttreatment. The CRST scores from 37 patients treated with unilateral MRgFUS were collected at 1, 3, 12, and 24 months (n = 37, 36, 35, and 17, respectively).
Although, clinical benefits seen at 3 months posttreatment were reduced at the 1-year timepoint, after 2 years, the dominant total score on CRST was significantly reduced showing sustained benefits of MRgFUS. This reflects that tremor at rest, while holding a posture, and while active was improved. Functional disability also improved, although a significant effect on specific tasks involving handwriting, drawing, and pouring was not seen.
The amount of tissue ablated in these patients was estimated and compared to patients’ functional outcomes. This showed that the volume of the initial lesion correlated with patients’ outcomes 1 year after treatment.