Unilateral Magnetic Resonance-Guided Focused Ultrasound Lesion of the Subthalamic Nucleus in Parkinson's Disease: A Prospective Study

Abstract

Background: Unilateral subthalamic nucleus (STN) ablation using magnetic resonance-guided focused ultrasound (MRgFUS) is being explored as a new treatment for asymmetric Parkinson's disease (PD).

Objectives: The aims were to study the efficacy and safety of this treatment in asymmetric PD patients and to characterize the lesions.

Methods: This prospective, single-center, open-label study evaluated asymmetric PD patients at 6 (n = 20) and 12 months (n = 12) after MRgFUS lesion of the STN. The primary outcome was the change in the Movement Disorders Society-Unified Parkinson's Disease Rating Scale, Part III (MDS-UPDRS III), score in off medication on the treated side and the adverse events (AEs) at 6-month follow-up. We also evaluated cognitive-neuropsychological changes, self-assessment of clinical improvement, and the correlation of the lesion volume with the motor outcomes.

Results: On the treated side, the MDS-UPDRS III score (mean difference = 13.8) and the scores in rigidity, bradykinesia, and tremor improved (P < 0.001) throughout the follow-up compared to baseline (at 6 months: rigidity mean difference = 2.8, improvement: 83.5%; bradykinesia mean difference = 6.0, improvement: 69.4%; tremor mean difference = 4.7, improvement: 91.5%). One patient had severe weakness in the treated hemibody, 1 had moderate dyskinesia, and 1 was in moderate confusional state that became mild (weakness) or completely resolved (dyskinesia and confusional state) at 6 months. The rest of the AEs were mild. We observed no clinically relevant changes in cognitive-neuropsychological tests. The percentage of ablation of the STN correlated with the improvement in the total MDS-UPDRS III and contralateral tremor scores (P < 0.05).

Conclusion: Unilateral MRgFUS lesion of the STN resulted in a significant motor improvement. We observed no persistent severe AEs, although mild, mostly transient AEs were frequent. © 2024 The Author(s). Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Keywords: Parkinson's disease; magnetic resonance–guided focused ultrasound; subthalamic nucleus (STN).

FIG. 1

(A) T1‐weighted images showing the STN (subthalamic nucleus) lesion. Correlation between the percentage of ablated STN and the reduction (B) in the MDS‐UPDRS III (Movement Disorders Society‐Unified Parkinson's Disease Rating Scale, Part III) total score, (C) in the tremor score on the treated side, (D) in the akinesia score on the treated side, and (E) in the total score of MDS‐UPDRS III on the treated side.

FIG. 2

(A) Change in the MDS‐UPDRS III (Movement Disorders Society‐Unified Parkinson's Disease Rating Scale, Part III) scores on the treated side during follow‐up. (B) Mean percentage of improvement in the MDS‐UPDRS III score on the treated side of each patient 6 months after treatment. (C) Patient Global Impression of Change (PGI‐C) during follow‐up. [Color figure can be viewed at wileyonlinelibrary.com]