Objective: To evaluate 5-year outcomes following unilateral GPi MRgFUS.

Background: MR‑guided focused ultrasound (MRgFUS) of the internal segment of globus pallidus internus (GPi) is an incisionless option for improving motor function and reducing medication-induced side effects in advanced Parkinson’s disease (PD). While benefits have been demonstrated for up to one-year, long-term outcomes have not yet been reported.

Method: PD participants enrolled in a multicenter sham-controlled (3:1 ratio) and followed up for five years. Assessments were performed at baseline and scheduled follow‑ups, at month-1, -3, -6, and -12, and then annually to 5-years post-treatment. Efficacy outcomes are reported as change from baseline to each follow-up time point in MDS-UPDRS Part III Upper-Lower Extremity (ULE) Score (OFF), MDS-UPDRS Part III Total (OFF), and Part IV Total. Data are summarized by descriptive statistics and represented as means and standard errors.

Results: Out of 94 participants, 69 underwent GPi MRgFUS and were evaluated at months 1 (n=69), 3 (n=67), 6 (n=50), years 1 (n=53); 2 (n=37); 3 (n=32), 4 (n=23), and 5 (n=20). At baseline (n=69), the mean (SE) MDS‑UPDRS Part III ULE (OFF) score was 29.1±1.23, Part III Total (OFF) was 42.7±14.3, and Part IV Total was10.7±3.5. At year 1 and 5, MDS‑UPDRS Part III ULE (OFF) was reduced from baseline by 22% (22.7±1.5) and 15% (24.6±2.1), respectively. MDS‑UPDRS Part III Total (OFF) was reduced by 22% (33.2±2.1) and 7% (39.7±3.1), respectively. Part III (OFF) subscore for the treated side remained improved from baseline (18.2±0.7) at 1 year (12.1±0.8) through year 5 (13.3±1.3). MDS‑UPDRS Part IV Total was reduced by 44% (6.0±0.5) and 48% (5.6±1.0), respectively. No new long‑term safety concerns emerged; most procedure‑related adverse events were mild and resolved within the first year.

Conclusion: In the subset of PD patients followed over time, unilateral GPi MRgFUS produced durable, clinically meaningful improvement in treated‑side motor function, OFF‑state motor severity, and motor complications, with benefits maintained through 5 years and no evidence of delayed adverse effects.

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MDS Abstracts - https://www.mdsabstracts.org/abstract/five-year-outcomes-following-unilateral-mr-guided-focused-ultrasound-pallidotomy-in-parkinsons-disease/