3-D Tractography FUS Ablation for Essential Tremor

September 2, 2026 updated by: University of North Carolina, Chapel Hill

3-D Tractography Focused Ultrasound Ablation for Essential Tremor

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.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Recruiting

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Detailed Description

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

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Estimated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
24

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.

Study Contact Backup

Study Locations

  • United States
    • North Carolina
      • Chapel Hill, North Carolina, United States, 27599
        • Recruiting
        • University of North Carolina at Chapel Hill
        • Contact:
        • Principal Investigator:
          • Vibhor Krishna, MD, SM
        • Contact:

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Diagnosis of moderate to severe ET agreed upon by at least two movement disorder trained physicians
  • Symptoms refractory to at least two medications
  • Stable essential tremor medication regimen for at least 4 weeks prior to screening
  • Willing and able to participate in all follow-up visits
  • Willing and able to undergo MR imaging.

Exclusion Criteria:

  • Uncontrolled hypertension
  • Medically unstable coronary artery disease
  • Coagulopathy with inability to temporarily stop any antithrombotic medication
  • Tremor disorders other than ET (e.g., Parkinson disease, traumatic tremor, alcohol or drug dependent tremor that remains after at least 2 weeks of abstinence etc.)
  • Unwilling or unable to undergo tremor surgery while awake
  • Significant and non-correctible motion artifact in imaging
  • Pregnant at the time of enrollment or preoperative evaluation
  • Dementia
  • History of psychosis
  • Prior brain surgery that could influence the focused ultrasound procedure outcomes, including deep brain stimulation
  • Botulinum toxin injection in the tremor-impacted areas three months prior to the baseline assessment and until 3-months after Vim-FUSA
  • does not qualify for FDA-approved clinical use based on current FDA labeling except that skull density ratio ≤ 0.4 will be allowed for this study
  • Any significant issue raised by the neurologist or neurosurgeon that may compromise participant safety or potentially interfere with study interpretation.
  • non-English speaking

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: N/A
  • Interventional Model: Single Group Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: 3-D Tractography Vim FUSA
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).
Other Names:
  • 3-D Tractography

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Number of Participants without Side Effects
Time Frame: during the surgical procedure
Feasibility is defined as the ability to complete the procedure without side effects.
during the surgical procedure
Absolute Change in Tremor
Time Frame: Baseline, Month 3
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).
Baseline, Month 3
Relative Change in Tremor
Time Frame: Baseline, Month 3
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).
Baseline, Month 3

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Number of Participants with Procedure-Related Side Effects
Time Frame: 3 months after the surgical procedure
Prevalence and severity of procedure-related side effects measured by the following: ataxia (SARA), speech disturbance (VHI), sensory loss (SWME), muscle weakness (MRC)
3 months after the surgical procedure
Relative Change in Tremor-Related Quality of Life
Time Frame: 3 months after the surgical procedure
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.
3 months after the surgical procedure
Number of Participants Who Are Satisfied with Treatment
Time Frame: 3 months after the surgical procedure
Measured using a single question asking about patient satisfaction ranging from 1 to 5 with higher scores indicating higher satisfaction.
3 months after the surgical procedure

Other Outcome Measures

Other Outcome Measures

For clinical trials, a planned measurement described in the protocol that is used to determine the effect of an intervention/treatment on participants. For observational studies, a measurement or observation that is used to describe patterns of diseases or traits, or associations with exposures, risk factors, or treatment. Types of outcome measures include primary outcome measure and secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Change in Tremor Based on Video Assessment
Time Frame: Baseline, during the surgical procedure
Upper extremity tremors will be measured by video recording using i-Phone set-up.
Baseline, during the surgical procedure
Change in Gait Based on Video Assessment
Time Frame: Baseline, during the surgical procedure
Gait will be measured by video recording using i-Phone set-up.
Baseline, during the surgical procedure

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
University of North Carolina, Chapel Hill

Collaborators

Collaborators

An organization other than the sponsor that provides support for a clinical study. This support may include activities related to funding, design, implementation, data analysis, or reporting.
University of Missouri-Columbia
National Institute of Neurological Disorders and Stroke (NINDS)
University of Pittsburgh

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Principal Investigator: Vibhor Krishna, MD, University of North Carolina at Chapel Hll

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
February 28, 2024

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
February 28, 2028

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
February 28, 2028

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
March 19, 2024

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
March 19, 2024

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
March 26, 2024

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
September 8, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
September 2, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
August 1, 2026

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • 23-2431
  • 1R01NS125386-01 (U.S. NIH Grant/Contract)

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

YES

IPD Plan Description

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.

IPD Sharing Time Frame

Beginning 9 and continuing for 36 months following publication

IPD Sharing Access Criteria

Investigator has approved IRB, IEC REB and an executed data use/sharing agreement with UNC.

IPD Sharing Supporting Information Type

  • STUDY_PROTOCOL
  • SAP

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

Yes

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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