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

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.