Study Compares FUS Unilateral Thalamotomy vs FUS Subthalamotomy in People with Medication Refractory Tremor

Research presented at the 2024 International Congress of Parkinson’s Disease and Movement Disorders compared the effects of unilateral focused ultrasound subthalamotomy (FUS-STN) with unilateral focused ultrasound of the ventral intermediate thalamic nucleus (FUS-Vim) in participants with medication refractory Parkinsonian tremor. Results suggest that FUS-STN was associated with more sustained tremor control and a better effect on bradykinesia long-term compared with FUS-Vim.

Methods: The retrospective, 2-centers included investigators from the Christian-Albrechts-Universität of Kiel, Germany and the Centro Integral de Nueorciencias (CINAC) of the University Hospital HM Puerta del Sur in Madrid, Spain. The study included 63 consecutive participants with medication refractory Parkinsonian tremor who received either FUS-Vim (n=23) or FUS-STN (n=40). Participants had equivalent tremor severity at baseline (5.7±1.5 vs 5.9±2.5).

Primary Outcome: The difference in tremor improvement through 12 months of follow-up per the MDS–Unified Parkinson’s Disease Rating Scale (MDS-UPDRS-III) on the treated side of the body.

Key findings

• Efficacy at 4 Months: The treated side of the body showed significant improvement in tremor (P<.001), which was equivalent in both groups.
• Efficacy at 12 Months: FUS-STN was associated with greater improvement in tremor vs FUS-Vim (mean change, 76.1±31.6% vs 35.2±52.1%; P<.001).
• Effect on Bradykinesia: Bradykinesia symptoms were reduced to a greater degree for people who received FUS-STN vs FUS-Vim.

Safety Profile

• Weight gain and dyskinesia occurred more frequently after FUS-STN.
• Dysgeusia, perioral, and finger paresthesias occurred only after FUS-Vim.
• In both groups, most adverse events (AEs) were mild and resolved by 12 months.