Unilateral focused ultrasound subthalamotomy in early Parkinson’s disease: a pilot study

Abstract

BackgroundUnilateral focused ultrasound subthalamotomy (FUS-STN) improves motor features of Parkinson’s disease (PD) in moderately advanced patients. The less invasive nature of FUS makes its early application in PD feasible. We aim to assess the safety and efficacy of unilateral FUS-STN in patients with PD of less than 5 years from diagnosis (early PD).MethodsProspective, open-label study. Eligible patients with early PD had highly asymmetrical cardinal features. The primary outcome was safety, defined as treatment-related adverse events at 6 months. Secondary outcomes included efficacy, assessed as motor improvement in the Movement Disorders Society-Unified Parkinson’s Disease Rating Scale (MDS-UPDRS), motor fluctuations, non-motor symptoms, daily living activities, quality of life, medication and patients’ impression of change.ResultsTwelve patients with PD (median age 52.0 (IQR 49.8–55.3) years, median time from diagnosis 3.0 (2.1–3.9) years) underwent unilateral FUS-STN. Within 2 weeks after treatment, five patients developed dyskinesia on the treated side, all resolved after levodopa dose adjustment. One patient developed mild contralateral motor weakness which fully resolved in 4 weeks. One patient developed dystonic foot and another hand and foot dystonia. The latter impaired gait and became functionally disabling initially. Both cases were well controlled with botulinum toxin injections. The off-medication motor MDS-UPDRS score for the treated side improved at 12 months by 68.7% (from 14.5 to 4.0, p=0.002), and the total motor MDS-UPDRS improved by 49.0% (from 26.5 to 13.0, p=0.002). Eleven patients (92%) reported global improvement 12 months after treatment.ConclusionUnilateral FUS-STN may be safe and effective to treat motor manifestations in patients with early PD. A larger confirmatory trial is warranted.Trial registration numberNCT04692116

Skull Density Ratio as Arm‐Allocation Parameter for a Controlled Focused Ultrasound Trial in Parkinson's Disease

“…Admittedly, patients with SDR between 0.3 and 0.4 may nowadays be treated, 13 although at the cost of low thermal efficiency. 3 Our experience 5 , 6 , 7 with FUS‐STN suggests that an SDR below 0.4 is difficult to achieve adequate treatment and, in our practice, we rarely admit patients with lower SDRs for FUS‐STN treatment.…”

“…In order to use SDR cut‐offs as an allocation strategy we have ascertained whether or not SDR values show any relationship with main clinical or demographic features in a large cohort of PD patients who were considered potential candidates for FUS treatment of the subthalamic nucleus (FUS‐STN). We have centered the analysis on STN ablation (ie, subthalamotomy) because it is the primary target for functional neurosurgical treatments of PD worldwide and we have carried out several studies with this approach 5–7 …”

“…We have centered the analysis on STN ablation (ie, subthalamotomy) because it is the primary target for functional neurosurgical treatments of PD worldwide and we have carried out several studies with this approach. 5 , 6 , 7 …”