Focused ultrasound subthalamotomy improves motor signs in asymmetric Parkinson’s disease
Focused ultrasound subthalamotomy improved motor features in a group of patients with asymmetric signs of Parkinson’s disease, although adverse events were “frequent,” according to results published in The New England Journal of Medicine.
“Focused ultrasound thalamotomy has been approved by the FDA to treat essential and parkinsonian tremors,” Raúl Martínez-Fernández, MD, PhD, of the University Hospital HM Puerta del Sur and CEU San Pablo University in Mostoles, Spain and the Network Center for Biomedical Research on Neurodegenerative Diseases at the Carlos III Institute in Madrid, and colleagues wrote. “Results from two uncontrolled studies have suggested that focused ultrasound subthalamotomy and pallidotomy performed on one side may reduce motor manifestations of Parkinson’s disease.”
Martínez-Fernández and colleagues performed a prospective, randomized, sham-controlled, double-blind trial in patients with PD asymmetry index scores above 1.5. Of 40 patients, 27 (mean age, 56.6 years; men, 59%) received focused ultrasound subthalamotomy and 13 received a sham surgery (mean age, 58.1 years; men, 77%). Researchers assessed complications related to the procedure, the primary safety outcome, at 4 months. Between-group differences in Movement Disorder Society-Unified Parkinson’s Disease Rating Scale motor score (MDS-UPDRS III) changes from baseline to 4 months in the absence of antiparkinsonian medications served as the primary efficacy outcome.
The researchers observed a between-group difference in MDS-UPDRS III score of 8.1 points (95% CI, 6-10.3). Among patients treated with focused ultrasound subthalamotomy, scores decreased by 9.8 points (95% CI, 8.6-11.1) compared with a 1.7-point decrease (95% CI, 0.0-3.5) among patients who received the sham surgery. Specifically, the active treatment group showed a decline in the mean MDS-UPDRS III score for the more affected side from 19.9 at baseline to 9.9 at 4 months. The control group experienced a decline from 18.7 at baseline to 17.1 at 4 months.
The researchers wrote that adverse events “were frequent and persisted in several patients,” which they said was “similar to outcomes in uncontrolled series of stereotactic radiofrequency subthalamotomy for the treatment of PD.”
The most common adverse events in the active treatment group included: dyskinesia in the off-medication state in 6 patients and in the on-medication state in 6 patients, which persisted in 3 patients and 1 patient, respectively, at 4 months after the procedure; weakness on the treated side in 5 patients, which persisted in 2 patients at 4 months; speech disturbance in 15 patients, which persisted in 3 patients at 4 months; facial weakness in 3 patients, which persisted in 1 patient at 4 months; and gait disturbance
in 13 patients, which persisted in 2 patients at 4 months. Some of these deficits remained at 12 months in 6 patients in the active treatment group, according to the researchers. However, they also noted that these results align with outcomes seen in uncontrolled series of stereotactic radiofrequency subthalamotomy for PD.
“In this trial involving a selected group of patients with markedly asymmetric PD, we found that focused ultrasound subthalamotomy performed in one hemisphere resulted in improved motor scores at 4 months but was associated with adverse events, including dyskinesias and other neurologic complications,” the researchers wrote. “Longer-term and larger trials are needed to determine the role of focused ultrasound subthalamotomy in the management of PD and its effect as compared with other available treatments, including deep-brain stimulation.”