A Multi-Center, Randomized, Controlled Trial of Unilateral Focused Ultrasound Thalamotomy for Essential Tremor (S27.004)

ABSTRACT

Objective: To determine efficacy and safety of unilateral focused ultrasound thalamotomy for refractory essential tremor Background: Recent advances in ultrasound transducer technology allow ultrasound to be transmitted with precision through the human skull. Early pilot studies suggest that MR guided focused ultrasound can be used to create successful VIM thalamic ablations in patients with essential tremor. Methods: Seventy-six patients with severe, medication-refractory essential tremor were randomized 3:1 to receive a unilateral focused ultrasound thalamotomy or a sham procedure. Tremor was rated 3 months post-operatively by blinded randomized videotapes rated at a central site. Additional quality of life measures were obtained at baseline, 3 months, 6 months, and 12 months. Safety was determined by monitoring adverse events throughout the study period. Results: Contralateral hand tremor in the ultrasound group, the primary endpoint improved 49[percnt] at 3 months (18.09 +4.81 to 9.55 + 5.06, p<0.001) compared to no change in sham procedures (16.00 + 4.42 to 15.75 + 4.90). The effect was maintained at one year (10.89+4.86). Functional measures of disability (p<0.001) and quality of life (p<0.001) reported by the patients were statistically improved compared to the sham cohort. There were only two serious adverse events reported in the treatment group: persistent sensory loss from the thalamotomy procedure and an unrelated TIA. Conclusion: High intensity focused ultrasound can be delivered through the intact skull to make precise ablations deep in the brain. MR guided focused ultrasound thalamotomy improves hand tremor in ET and was well tolerated. Both efficacy and adverse event profile compare favorably to deep brain stimulation. Additional studies will be need to determine the long term durability of the treatment.

Disclosure: Dr. Ondo has received personal compensation for activities with Teva, Ipsen, UCB, Merz, and Lundbeck as a speaker and consultant. Dr. Elias has nothing to disclose.