Stepwise dual-target magnetic resonance-guided focused ultrasound in tremor-dominant Parkinson disease: One-year follow-up

Background and Purpose

Magnetic resonance-guided focused ultrasound (MRgFUS) is a nonsurgical treatment for Parkinson disease (PD). Some selected anatomical structures can be targeted by MRgFUS in PD. However, there is no uniform target yet. We have reported that stepwise dual-target MRgFUS was successfully applied to treat refractory tremors with akinetic–rigid features in PD. It generated two precise thermal ablations in the ventral intermediate nucleus (VIM) and pallidothalamic tract (PTT). Here, we report more PD patients to verify the safety and efficacy of stepwise dual-target MRgFUS.

Methods

Ten tremor-dominant PD patients (mean age = 66.7 ± 3.2 years, eight men) received the stepwise dual-target MRgFUS treatment with a series of primary and secondary outcome measures. The VIM and PTT were navigated based on brain magnetic resonance images. Outcome measures were categorized into primary and secondary assessments. The primary outcome measures consisted of resting tremor, action/kinetic tremor, rigidity, and bradykinesia. Secondary outcome measures encompassed non-motor symptoms scale of PD. Data collected at follow-up time points, including 1 day, 3 months, 6 months, and 1 year posttreatment, were compared with baseline data.

Results

The severity of tremor and motor deficits represented by Clinical Rating Scale for Tremor parts A and B during off-medication status and Unified Parkinson's Disease Rating Scale III on the treated side were significantly improved (p < 0.05 by paired t-test) at 1-year follow-up. At the 1-year follow-up, significant improvement was observed in the non-motor symptoms scale. Additionally, no severe adverse effects were reported, except temporary treatment-related discomfort during the procedure.

Conclusions

In conclusion, stepwise dual-target MRgFUS emerges as a safe and effective therapeutic modality for PD patients, particularly in addressing medication-refractory tremor and akinetic–rigid syndrome.