Objective: To assess the efficacy of MRgFUS thalamotomy in patients with ET.

Background: MRgFUS thalamotomy can improve tremor in patients with  refractory ET[1].

Method: Data was collected for  ET patients who underwent unilateral MRgFUS thalamotomy in Sheba medical center: demographic data, operational parameters, preoperative and postoperative tremor assessments (Clinical Rating Scale for Tremor (CRST) and Tremor Research Group Essential Tremor Rating Scale (TETRAS)). The differences in scores were analyzed by Wilcoxon signed rank test.

Results: Between November 2015 and February 2022, 52 patients with ET  were treated with MRgFUS. Most were treated for the right hand (46, 88.4%).
Most were male (39, 75%), The average age of the subjects was 72.96±8.04. The Average duration of disease was 23±17.12 years.
The mean skull density ratio (SDR) was 0.53±0.1(0.36-0.8), mean number of sonications was 11.64±4.66 (5-22). The mean maximal temperature obtained was 57.2±2.17(51-62) °C.
We compared preoperative assessments to assessments performed during the first 12 months postoperatively of 42 patients who had valid pre and postoperative assessments.
 The  average score for CRST A (tremor at rest and action) was reduced from an average of 15.17±8.17 to 10.35±6.32. The average CRST Part B  score (kinetic tremor during tasks) was reduced from 19.23±5.99 to 12.4±5.75. The average  CRST Part C  (functional disability) was reduced from 13.24±4.38 to  3.63±5.32. Tetras  average score for performance was reduced from 23.75±6.67 to 15.62±5.51 and the average score for ADL part was reduced from 25.34±6.84 to 6.72±9.44.  All reductions were significant (P<0.0001) when comparing each patient’s individual score.A significant post operative improvement was also noticed at later time points-CRST B (36 month,P=0.03) and C(36 months, P = 0.01).
When assessing the reduction of tremor score for the treated hand using the combined CRST part A scores for rest, postural and action tremor- a significant  reduction was demonstrated  from 6.97±2.71 at to 2.02±3.24 during the first 12 months (N=39,P<0.0001), 2.91±2.6 between 12-24 months(N=24,P<0.001) and 2.73±2.15 points between 24-36 months(N=15,P<0.01).

Conclusion: Our data shows that MRgFUS thalamotomy is an efficient treatment for refractory ET patients with improvement in  tremor severity and functional disability.

References: [1] Elias WJ, Lipsman N, Ondo WG, et al. A Randomized Trial of Focused Ultrasound
Thalamotomy for Essential Tremor. N Engl J Med 2016;375:730-739.

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