Focused Ultrasound Thalamotomy for Tremor in Parkinson's Disease: Outcomes in a Large, Prospective Cohort

Abstract

BackgroundMagnetic resonance guided focused ultrasound (MRgFUS) is United States Food and Drug Administration approved for the treatment of tremor‐dominant Parkinson's disease (TdPD), but only limited studies have been described in practice.ObjectivesTo report the largest prospective experience of unilateral MRgFUS thalamotomy for the treatment of medically refractory TdPD.MethodsClinical outcomes of 48 patients with medically refractory TdPD who underwent MRgFUS thalamotomy were evaluated. Tremor outcomes were assessed using the Fahn‐Tolosa‐Marin scale and adverse effects were categorized using a structured questionnaire and clinical exam at 1 month (n = 44), 3 months (n = 34), 1 year (n = 22), 2 years (n = 5), and 3 years (n = 2). Patients underwent magnetic resonance imaging <24 hours post‐procedure.ResultsSignificant tremor control persisted at all follow‐ups (P < 0.001). All side effects were mild. At 3 months, these included gait imbalance (38.24%), sensory deficits (26.47%), motor weakness (17.65%), dysgeusia (5.88%), and dysarthria (5.88%), with some persisting at 1 year.ConclusionsMRgFUS thalamotomy is an effective treatment for sustained tremor control in patients with TdPD. © 2023 International Parkinson and Movement Disorder Society.

Motor and non-motor outcome in tremor dominant Parkinson’s disease after MR-guided focused ultrasound thalamotomy

“…Gait disturbances and paraesthesias were the most common side effects [32,40]. Consistent with observations in essential tremor patients [17,41], we also observed taste disturbances and delayed occurrence of involuntary movements, most likely corresponding to "thalamic" dystonia.…”

“…Bradykinesia and rigidity of the treated side improved initially but this effect faded over time-either because of disease progression or more likely edema regression. Previous studies targeting the VLpv nucleus, reported diminishing effects on rigidity, too [32]. The adjacent anterior (VLa) and posterodorsal part (VLpd) of the ventralolateral nucleus (corresponding to the ventri-oralis anterior (Voa) and posterior (Vop) nucleus in the Schaltenbrand atlas [6]), which receive pallidal projections, are considered to be associated with rigidity [34] and thus might be affected by perilesional edema after VLpv ablation.…”

How to Use the New European Academy of Neurology/Movement Disorder Society European Section Guideline for Invasive Therapies in Parkinson's Disease

“…7,33,57 VIM-MRgFUS may be an alternative for tremor-dominant older PD patients with asymmetric tremor presentation as it achieves a relevant unilateral tremor reduction confirmed by lower-quality evidence. 25,59 Evidence for long-term efficacy is increasing, but still limited for MRgFUS, 68,69 whereas for DBS long-term efficacy is well established. 31,32 Potential Limitations.…”

Magnetic resonance-guided focused ultrasound thalamotomy for essential tremor patients with low skull density ratio: a case-matched analysis

“…Furthermore, patients with SDR <0.45 may represent 30–40% of ET patients who could potentially benefit from MRgFUS, especially East Asian patients who tend to have lower SDRs ( 15–17 ). The FDA’s SDR cutoff of 0.45 (±0.05) may therefore exclude a significant proportion of patients who could benefit from an effective therapy with a growing number of indications ( 18 ).…”