Magnetic resonance-guided focused ultrasound (MRgFUS) can stably suppress essential tremor (ET) long-term, according to 2-year follow-up data from a multinational study, published in the Annals of Neurology.

"Tremor suppression after MRgFUS thalamotomy for ET is stably maintained at 2 years. Latent or delayed complications do not develop after treatment," the authors noted.

“MRI-guided focused ultrasound thalamotomy is extremely appealing to patients with severe tremor because it is an ‘incisionless’ procedure. Doctors value the ability to monitor a deep-brain procedure in real time with MRI," said senior author Dr. Jeffrey Elias, a professor of neurological surgery at the University of Virginia in Charlottesville.

"This study, presenting two-year data, is important to show that reasonable outcomes are already being achieved. At this early stage in the technology (which has only been FDA approved since July 2016), considerable opportunity remains to refine the procedure so it becomes faster, more reliable, and more durable," he said.

“As a neurologist who specializes in treating patients with tremors, I find having more tools at our disposal is invaluable. There is no one-size-fits-all approach to patient care. With the option of MRgFUS, we are able to discuss more considerations with patients so we can provide them with the treatment that best fits with their goals," noted coauthor Dr. Binit B. Shah, assistant professor of neurology at the University of Virginia.

The researchers studied 76 patients (mean age, 71; mean disease duration, 17 years; 68% male; 83% right-handed). All had moderate-to-severe ET and had not responded to at least two trials of medical therapy before being enrolled in a randomized trial of unilateral MRgFUS versus a sham procedure.

Baseline mean total Clinical Rating Scale for Tremor score of tremor severity was 49.5 (out of a possible 152), and the mean hand tremor score was 19.8 (maximum possible score, 32).

For the 2-year evaluation, the researchers had data from 67 participants who had undergone MRgFUS. By two years, mean hand tremor scores improved by 56%, from 19.8 at baseline (in the 76 original patients) to 8.8 (in 67 patients). Two patients had no hand tremor at 2 years. Also, the patients’ mean disability score improved by 60%, from 16.4 at baseline to 5.4 at 2 years.

According to the researchers, gait problems and paresthesias, in 10 patients each, were the most common adverse effects at one year, and five patients experience neurological adverse effects. By two years, no new delayed complications had occurred.

Dr. Michal T. Gostkowski, a neurologist at Cleveland Clinic, in Ohio, said in an email, "This gives another option to adequately address essential tremor. Currently, medical therapy provides only marginal improvement for the vast majority of patients. This is a potential option for patients resistant, for whatever reason, to deep-brain stimulation."

"This is an interesting and important study," noted Dr. Patel, who was not involved in the study. "As a clinician who cares for patients with ET, these maintained benefits are exciting. At the same time, the tremor improvement is somewhat lower than deep-brain stimulation, and the rates of lasting complications may be concerning to patients."