Is Unilateral Focused Ultrasound Thalamotomy as Effective and Safe as Unilateral Deep Brain Stimulation for Essential Tremor? – A critical evaluation

BACKGROUND: Focused ultrasound (FUS) thalamotomy has become a common surgical treatment for essential tremor (ET), in some settings partially replacing deep brain stimulation (DBS). However, no randomized comparative studies have been performed. A review directly comparing unilateral FUS thalamotomy and unilateral DBS is therefore warranted. SUMMARY: A systematic literature search identified studies of thalamotomy FUS or thalamic DBS for ET. Eligible studies reported mean values for predefined items of the Clinical Rating Scale for Tremor (CRST) at 6-12 months follow-up. Studies with long-term outcomes (≥5 years) were also considered. Duplicate or overlapping cohorts were excluded. Thirteen short-term FUS studies (427 patients) and six DBS studies (307 patients) met inclusion criteria. Mean age was comparable, though the FUS cohort showed greater gender imbalance. Improvement in total CRST scores did not differ significantly between FUS and DBS (53% vs. 56%). DBS was associated with significantly greater improvement in contralateral hand tremor (86% vs. 72%), combined hand tremor and function (82% vs. 59%), and activities of daily living (71% vs. 65%). Long-term data were limited: two FUS studies (66 patients) and two DBS studies (36 patients) met criteria. Adverse event profiles differed substantially, with complications more frequent and more often persistent following FUS. KEY MESSAGES: Both treatments provide clinically meaningful tremor reduction, though DBS appears to offer greater overall improvement. Permanent side effects after FUS are relatively common but mostly mild. Randomized trials comparing DBS and FUS are needed, particularly regarding side effects and quality of life.