Research findings offered during the 81st American Association of Neurological Surgeons (AANS) Annual Scientific Meeting show that the use of transcranial MR-guided focused ultrasound for producing a thalamotomy can have significant positive effects on subjects suffering from essential tremor.

A preliminary clinical trial suggested that acoustic energy could be delivered precisely to generate a focal stereotactic ablation deep within the brain. In an FDA-approved clinical trial, 15 patients with medication-refractory essential tremor underwent transcranial MR-guided focused ultrasound thalamotomy targeting the Vim nucleus. Adverse events were recorded throughout the study, with comprehensive neurologic assessments for sensation, gait, strength and balance. A 160-point validated rating scale of tremor was used to assess the procedure’s efficacy on the subjects, and a quality-of-life-inessential-tremor questionnaire was obtained at pre, three-months and twelve-months post treatment. In addition, MR assessments were made of the lesions at one day, one week, one month and three months. The study is titled “The One Year Results of a Phase I Study of Transcranial MR Guided Focused Ultrasound Thalamotomy for the Treatment ofMedication Refractory Essential Tremor.”

The results showed a 67% reduction in contralateral hand tremor at one year. This unilateral reduction of tremor in the dominant hand resulted in substantial improvements in daily disabilities (83%) and quality of life as assessed by clinicians and the subjects. Adverse events from the therapy were minimal and consisted mostly of mild paresthesia of the face or hand, but it is important to note that this preliminary feasibility study was not powered to determine the true safety and efficacy of the treatment. The researchers concluded that this initial investigation of transcranial MR-guided focused ultrasound thalamotomy seems feasible and safe enough to proceed with more comprehensive clinical trials.