An interventional study of MR-guided Focused Ultrasound Ablation in Essential Tremor, sponsored by University of North Carolina, Chapel Hill. Recruiting at 1 site in United States. Open to participants aged 22 Years and older. Per ClinicalTrials.gov, last updated 2026-09-08.
Sponsored by University of North Carolina, Chapel Hill · Not applicable, Interventional, and Treatment
The investigators propose to advance Vim-FUSA (Ventral Intermediate Nucleus - Focused Ultrasound Ablation) with the support of 3-D tractography, a neuroimaging technique to visually represent nerve tracts within the brain. The investigators hypothesize that 3-D tractography Vim-FUSA will improve the Vim ablation compared to standard Vim-FUSA and prove safe and feasible in the clinical setting. The investigators also hypothesize that intraoperative magnetic resonance (i-MR) monitoring will differentiate ablated tissue from immediate perilesional edema and accurately predict the Vim-FUSA clinical outcomes.
Essential tremor (ET) is a common neurological disorder and a leading cause of functional and psychological disabilities that can be difficult to suppress with oral medications, many of which have considerable side effects limiting adequate dosing. As a result, up to 20% of ET patients cannot achieve satisfactory control of their symptoms and must consider interventional options. Focused ultrasound ablation (FUSA) of the ventral intermediate nucleus (Vim) is an FDA-approved and Medicare-reimbursed procedure for ET resistant to medications that can selectively ablate the brain area associated with tremor without the need for surgical incisions or anesthesia. The success of Vim-FUSA depends on the ability to accurately ablate 70% of the Vim volume without lesioning neighboring structures, a goal that is complicated by technical challenges in three critical phases of the procedure: planning (identifying the Vim location and extension); delivery (ablating the Vim volume with adequate accuracy); and monitoring (confirming Vim ablation with reliable intraoperative imaging). The investigators propose to advance Vim-FUSA with the support of 3-D tractography, a neuroimaging technique to visually represent nerve tracts within the brain. The investigators hypothesize that 3-D tractography Vim-FUSA will improve the Vim ablation compared to standard Vim-FUSA and prove safe and feasible in the clinical setting. The investigators also hypothesize that intraoperative magnetic resonance (i-MR) monitoring will differentiate ablated tissue from immediate perilesional edema and accurately predict the Vim-FUSA clinical outcomes. Aim 1. Estimate and characterize the improvement in Vim ablation achieved with 3-D tractography Vim-FUSA vs. standard Vim-FUSA in an experimental controlled animal study. Through an experimental animal study, the investigators will characterize the Vim ablation delivered with 3-D tractography Vim-FUSA in one hemisphere (experimental group) vs. standard Vim-FUSA in the opposite hemisphere (control group). Aim 2. Test safety, feasibility, and preliminary efficacy, and estimate effect size of 3-D tractography Vim-FUSA in a phase-II, two-groups, pre-post interventional human study. In a human study, the investigators will test the safety and feasibility of ablating 70% of the Vim volume while checking for side effects with intraoperative clinical testing. Tremor assessments will be videotaped at baseline and 12 weeks and compared, in a blinded fashion, with age-sex matched controls randomly selected from the video repository of the two FDA-regulated studies of standard Vim-FUSA at baseline and 12 weeks. Aim 3 (Exploratory). Assess the accuracy of i-MR in differentiating tissue ablation from immediate perilesional edema and its utility in predicting Vim-FUSA clinical outcomes. In the experimental animal study, the investigators will estimate and compare the accuracy of conventional and non-conventional i-MR in differentiating tissue necrosis from perilesional edema. In the interventional human study, the investigators will evaluate the utility of i-MR in predicting Vim-FUSA clinical outcomes
272 studies on the registry are indexed under Essential Tremor; 75 are open to participants now.
This study's planned enrollment of 24 is close to the median of 25 across 189 interventional studies indexed under Essential Tremor.
Browse Essential Tremor studies →University of North Carolina, Chapel Hill is the lead sponsor of 1,372 studies on the registry; 133 are open to participants now.
Of its 161 completed or terminated interventional studies of FDA-regulated products, 139 (86%) have results posted.
Counted across the registry records on this site, refreshed daily.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Relapsed: the illness came back after treatment had worked. Refractory: it did not respond to treatment, or stopped responding while still on it.
Relapsed and refractory
Relapsed: the illness came back after treatment had worked. Refractory: it did not respond to treatment, or stopped responding while still on it.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Twenty-four consecutive essential tremor (ET) participants undergoing Vim FUSA using 3-D tractography will be assessed at baseline and Month 3.
Device: MR-guided Focused Ultrasound Ablation
3-D tractography Vim-FUSA -D tractography Vim-FUSA will be carried out as follows: (a) head shaving and placement of the stereotactic frame (Integra radionics frame, Integra Lifesciences, NJ, USA) secured to the skull with transcutaneous screws; (b) positioning on the procedure table and placement of the ultrasound transducer; (c) acquisition of conventional magnetic resonance (MR) imaging and co-registration with the CT head and 3-D tractography imaging acquired pre-surgically; (d) exploration of the target area with subtherapeutic sonications; (e) intraoperative monitoring with clinical testing of tremor and side effects with a standardized protocol. (f) Therapeutic sonications in the target area to deliver definitive ablation followed by clinical testing of tremor and side effects with a standardized protocol as described in section (e).
Also known as: 3-D Tractography
Number of Participants without Side Effects
Feasibility is defined as the ability to complete the procedure without side effects.
Time frame: during the surgical procedure
Absolute Change in Tremor
The absolute change from baseline to Month 3 follow-up in upper extremity Tremor-Motor scores for the treated side is a sub-scale of Clinical Rating Scale for Tremor (CRST) Part A and Part B sum used to measure treated-side upper extremity tremor changes over time. Tremor-motor scores range from 0-32 points. Individual subject's scores at Baseline and 3 Months used to calculate absolute change from baseline and averaged across subjects. High absolute change from baseline is better (shows improvement).
Time frame: Baseline, Month 3
Relative Change in Tremor
The relative change from baseline to Month 3 follow-up in upper extremity Tremor-Motor scores for the treated side is a sub-scale of Clinical Rating Scale for Tremor (CRST) Part A and Part B sum used to measure treated-side upper extremity tremor changes over time. Tremor-motor scores range from 0-32 points. Individual subject's scores at Baseline and 3 Months used to calculate relative change from baseline and averaged across subjects. High relative change from baseline is better (shows improvement).
Time frame: Baseline, Month 3
Number of Participants with Procedure-Related Side Effects
Prevalence and severity of procedure-related side effects measured by the following: ataxia (SARA), speech disturbance (VHI), sensory loss (SWME), muscle weakness (MRC)
Time frame: 3 months after the surgical procedure
Relative Change in Tremor-Related Quality of Life
The Quality of Life Essential Tremor Questionnaire (QUEST) will be used to assess tremor-related quality of life. QUEST has scores ranging from 0 to 100 with higher scores indicating worse disability.
Time frame: 3 months after the surgical procedure
Number of Participants Who Are Satisfied with Treatment
Measured using a single question asking about patient satisfaction ranging from 1 to 5 with higher scores indicating higher satisfaction.
Time frame: 3 months after the surgical procedure
Change in Tremor Based on Video Assessment
Upper extremity tremors will be measured by video recording using i-Phone set-up.
Time frame: Baseline, during the surgical procedure
Change in Gait Based on Video Assessment
Gait will be measured by video recording using i-Phone set-up.
Time frame: Baseline, during the surgical procedure
Plan to share: Yes — De-identified individual data that supports the results will be shared beginning 9 to 36 months following publication provided the investigator who proposes to use the data has approval from an Institutional Review Board (IRB), Independent Ethics Committee (IEC), or Research Ethics Board (REB), as applicable, and executes a data use/sharing agreement with UNC.
Supporting information: Study protocol, Statistical analysis plan
Time frame: Beginning 9 and continuing for 36 months following publication
Access criteria: Investigator has approved IRB, IEC REB and an executed data use/sharing agreement with UNC.
No publications or documents are linked to this record.
Started Feb 2024 (actual). Primary completion is estimated for Feb 2028, 48 months after the start.
Of 77 non-industry interventional studies with no phase under Essential Tremor, half reached primary completion within 52 months of starting (the median), counting those still running; a quarter within 26. This study's planned 48 months is close to that.
Counting every sponsor, half of 95 studies reached it within 45 months; a quarter within 19 and three quarters within 93.
How these figures are worked out, and which studies are left out of them.
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