First use of MRI-guided focused ultrasound to treat patients with essential tremor in Russia

Abstract

Introduction. Treatment with MRI-guided focused ultrasound (MRgFUS) is a new, non-invasive surgical technique for treating extrapyramidal movement disorders. This article presents the first use of MRgFUS in Russia for treating patients with essential tremor (ET). Materials and methods. Patients (n = 26; 17 men and 9 women) aged 2182 years (median age 46.0 years) and with severe and refractory ET, underwent MRgFUS thalamotomy (ExAblate 4000, Insightec). One side was treated in 22 patients (left thalamus in 18 and right thalamus in 6), both sides were treated concurrently in two patients, and both sides were treated consecutively in two patients. Tremor was assessed using the Clinical Rating Scale for Tremor (CRST). Because international clinical specialists could not visit Russia due to the COVID-19 pandemic, MRgFUS was performed via telehealth on May 5, 2020, in a world first. Results. A satisfactory result was achieved in 25 (96%) out of 26 patients. CRST scores improved by 64.7% on the side of the operation, by 10.2% on the control side, and by 37.5% overall. Intraoperative side effects included headache during sonication (42.3%), vertigo (15.4%), nausea (11.5%), vomiting (7.7%), numbness (3.8%), ataxia (3.8%), and pathological response to cold exposure (3.8%). The symptoms resolved immediately after surgery. Unstable gait was noted in five patients, which completely resolved two weeks after surgery. Median postoperative follow-up duration was 109 days [53; 231], with a maximum of 625 days. No relapses (if the hyperkinesia had completely disappeared) or increased tremor (if reduced after surgery) were observed. Conclusion. The efficacy of MRgFUS for ET was 96%, with no long-term complications. Both bilateral concurrent and bilateral consecutive MRgFUS thalamotomy is possible, but its efficacy and safety should be assessed in a randomized study. In a world first, MRgFUS was successfully implemented using telehealth.