Bilateral Effects of Unilateral Pallidothalamic Tractotomy Using Focused Ultrasound in Parkinson's Disease

Abstract Background The efficacy of pallidothalamic tract (PTT)‐focused ultrasound (FUS) in the treatment of advanced Parkinson's disease (aPD) remains unclear. Objective This study aimed to evaluate the safety and efficacy of PTT‐FUS. Methods Nine patients with aPD underwent PTT‐FUS. Clinical assessments, including the Movement Disorder Society Unified Parkinson's Disease Rating Scale (MDS‐UPDRS), were conducted at baseline and 3 months after the first procedure, with contralateral procedure and clinical evaluation up to 12 months later. Results MDS‐UPDRS Part III on / off medication scores improved from 26.1 ± 15.4/54.4 ± 16.7 at baseline to 11.9 ± 9.6/26.6 ± 15.9 at 3 months after the unilateral procedure. The Unified Dyskinesia Rating Scale score improved from 25.0 ± 18.9 to 3.6 ± 7.0. Because of ipsilateral and axial symptom improvement, treatment was terminated after the unilateral procedure in seven patients. Adverse events included permanent freezing in one patient. Conclusions Unilateral PTT‐FUS improves wearing off and dyskinesia, with bilateral effects observed short term. © 2025 International Parkinson and Movement Disorder Society.