Conference Coverage
MRI-guided focused ultrasound thalamotomy reduces hand tremor in patients with essential tremor, according to data published August 25 in the New England Journal of Medicine. The technique also reduces disability and improves self-reported quality of life, said the researchers.
“We are excited to have this new noninvasive treatment option for patients who struggle every day with this debilitating neurologic disorder,” said Howard M. Eisenberg, MD, the R.K. Thompson Professor and Chair of Neurosurgery at the University of Maryland School of Medicine in Baltimore and an author of the study. “We saw an impressive reduction in tremors in hands and arms and an improvement in quality of life in patients who experienced no relief from medication.”
Howard M. Eisenberg, MD
Dr. Eisenberg and colleagues randomized 76 patients with moderate to severe essential tremor that had not responded to at least two trials of medical therapy to unilateral focused ultrasound thalamotomy or a sham procedure. The investigators administered the Clinical Rating Scale for Tremor (CRST) and the Quality of Life in Essential Tremor (QUEST) questionnaire to participants at baseline and at one, three, six, and 12 months. Videotaped tremor assessments were rated by an independent group of neurologists who were blinded to the treatment assignments. After three months, patients in the sham-procedure group were allowed to cross over to active treatment.
The study’s primary outcome was the between-group difference in the change from baseline to three months in hand tremor, rated on Parts A and B of the CRST. Secondary outcomes included functional limitations in daily activities, measured according to eight items in the disability subsection of the CRST; quality of life, assessed with the QUEST at three months; and the durability of the reduction in hand tremor at 12 months.
Hand-tremor scores improved by 8.5 points in the intervention group and by 0.2 points among controls. Improvement occurred in the hand contralateral to the thalamotomy. The between-group difference in the mean change was 8.3 points. The improvement in the thalamotomy group was maintained at 12 months (change from baseline, 7.2 points). Focused ultrasound thalamotomy also improved total disability score by 62% at three months, compared with 3% among controls, and the improvement was sustained at 12 months. Patients’ self-rated quality of life improved by 46% at three months in the intervention group and by 3% among controls.
Adverse events of thalamotomy included gait disturbance (36% of patients) and paresthesias or numbness (38% of patients). These adverse events persisted at 12 months in 9% and 14% of patients, respectively.
In an accompanying editorial, Elan D. Louis, MD, Chief of the Division of Movement Disorders at Yale University in New Haven, Connecticut, said that the study results are promising, particularly since the procedure, unlike traditional thalamotomy, does not require entering the skull with a probe. “Nevertheless,” he added, “there are several important concerns.” The first concern is the limited follow-up period. The sustained benefit beyond one year is not known. “This is particularly important because of tachyphylaxis, which is the second concern,” Dr. Louis wrote. Tremor score in the group that underwent focused ultrasound thalamotomy increased from 8.84 at one month to 10.89 at 12 months, an increase of 23%. A third concern is that the procedure did not achieve large improvements in everyone; the percentage change in tremor was less than 20% in nine of 56 patients. “Even with these concerns,” Dr. Louis said, “the procedure will take its place among other surgical procedures for medically refractory essential tremor.”
—Erik Greb and Glenn Williams
Suggested Reading
Elias WJ, Lipsman N, Ondo WG, et al. A randomized trial of focused ultrasound thalamotomy for essential tremor. N Engl J Med. 2016;375(8):730-739.
Louis ED. Treatment of medically refractory essential tremor. N Engl J Med. 2016;375(8):792-793.