ExAblate (Magnetic Resonance-guided Focused Ultrasound Surgery) for Treatment of Tremor

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. Identifier: NCT01932463
Recruitment Status : Completed
First Posted : August 30, 2013
Last Update Posted : August 30, 2013
Information provided by (Responsible Party):

Brief Summary:
A feasibility Study to Evaluate Safety and Initial Effectiveness of ExAblate Transcranial MR Guided Focused Ultrasound for Unilateral Thalamotomy in the Treatment of Tremor

Condition or disease Intervention/treatment Phase
Tremor Essential Tremor Device: ExAblate Transcranial System Not Applicable

Detailed Description:
The non-invasive high-intensity focused ultrasound has been coupled with high resolution MRI to provide precise, consistent treatments that can be monitored in real-time. The development of phased array transducers allows for tightly focused treatment volumes and for the ability to compensate for distortions by tissue inhomogeneities. The landmark advance in MRgFUS for neurosurgeons occurred as the ability to sonicate through the intact cranium was achieved with phased array transducers and acoustic modeling using CT reconstructions of the skull. By coupling HIFU with MRI, detailed treatment plans can be generated and intra-procedure real-time monitoring is available. Standard MR sequences have been shown to reliably predict tissue damage during thermal lesioning with ultrasound. The precision of the technology has already been demonstrated in animal models and is currently being investigated in humans with brain tumors and neuropathic pain syndromes. Unlike stereotactic radiosurgery, the treatment can be monitored continuously in real time with MRI and MR-thermography. We anticipate that a MRgFUS non-invasive thermal lesioning is similarly as safe as DBS (or other current procedure and will provide several years of benefit through reduction of contralateral motor symptoms and potential medication side effects in ET, while still permitting subsequent treatment with DBS should that become clinically desirable.

Study Type : Interventional  (Clinical Trial)
Actual Enrollment : 6 participants
Intervention Model: Single Group Assignment
Masking: None (Open Label)
Primary Purpose: Treatment
Official Title: A Feasibility Study to Evaluate Safety and Initial Effectiveness of ExAblate Transcranial MR Guided Focused Ultrasound for Unilateral Thalamotomy in the Treatment of Tremor
Study Start Date : May 2011
Actual Primary Completion Date : December 2012
Actual Study Completion Date : July 2013

Resource links provided by the National Library of Medicine

MedlinePlus related topics: Tremor Ultrasound

Arm Intervention/treatment
Experimental: ExAb;ate MRgFUS Device: ExAblate Transcranial System
MR Guided Focused Ultrasound
Other Names:
  • MRgFUS
  • FUS
  • Focused Ultrasound
  • MR Guided Focused Ultrasound

Primary Outcome Measures :
  1. Accuracy of Thalamotomy lesion [ Time Frame: 1 day ]
    Comparison of the stereotactic coordinates of the atlas to the lesion created in the brain.

Information from the National Library of Medicine

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Ages Eligible for Study:   18 Years to 80 Years   (Adult, Older Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No

Inclusion Criteria:

  1. Men and women, between 18 and 80 years, inclusive
  2. Patients who are able and willing to give consent and able to attend all study visits
  3. A diagnosis of ET as confirmed from clinical history and examination by a movement disorder neurologist
  4. Tremor refractory to adequate trials of at least two medications, one of which should be either propranolol or primidone. An adequate medication trial is defined as a therapeutic dose of each medication or the development of side effects as the medication dose is titrated.
  5. Vim nucleus of thalamus can be target by the ExAblate device. The Vim region of the thalamus must be apparent on MRI such that targeting can be performed with either direct visualization or by measurement from a line connecting the anterior and posterior commissures of the brain.
  6. Able to communicate sensations during the ExAblate MRgFUS treatment
  7. Postural or intention tremor severity score of greater than or equal to 2 in the dominant hand/arm as measured by the CRST rating scale.
  8. Stable doses of all medications for 30 days prior to study entry and for the duration of the study.
  9. May have bilateral appendicular tremor
  10. Significant disability due to essential tremor despite medical treatment (CRST score of 2 or above in any one of the items 16-23 from the Disability subsection of the CRST: [speaking, feeding other than liquids, bringing liquids to mouth, hygiene, dressing, writing, working, and social activities])
  11. Inclusion and exclusion criteria have been agreed upon by two members of the medical team.

Exclusion Criteria:

  1. Patients with unstable cardiac status including:

    • Unstable angina pectoris on medication
    • Patients with documented myocardial infarction within six months of protocol entry
    • Congestive heart failure requiring medication (other than diuretic)
    • Patients on anti-arrhythmic drugs
  2. Alcohol or drug abuse within the past 6 months
  3. Severe hypertension (diastolic BP > 100 on medication)
  4. Patients with standard contraindications for MR imaging such as non-MRI compatible implanted metallic devices including cardiac pacemakers, size limitations, etc.
  5. Known intolerance or allergies to the MRI contrast agent (e.g. Gadolinium or Magnevist) including advanced kidney disease
  6. Severely impaired renal function (estimated glomerular filtration rate < 30ml/min/1.73 m2) or receiving dialysis
  7. History of abnormal bleeding and/or coagulopathy
  8. Receiving anticoagulant (e.g. warfarin) or antiplatelet (e.g. aspirin) therapy within one week of focused ultrasound procedure or drugs known to increase risk or hemorrhage (e.g. Avastin) within one month of focused ultrasound procedure
  9. Active or suspected acute or chronic uncontrolled infection
  10. History of intracranial hemorrhage
  11. Cerebrovascular disease (multiple CVA or CVA within 6 months)
  12. Individuals who are not able or willing to tolerate the required prolonged stationary supine position during treatment (can be up to 4 hrs of total table time.)
  13. Symptoms and signs of increased intracranial pressure (e.g. headache, nausea, vomiting, lethargy, and papilledema)
  14. Untreated, uncontrolled sleep apnea
  15. Are participating or have participated in another clinical trial in the last 30 days
  16. Patients unable to communicate with the investigator and staff.
  17. Presence of any other neurodegenerative disease like parkinson-plus syndromes suspected on neurological examination. These include: multisystem atrophy, progressive supranuclear palsy, dementia with Lewy bodies, and Alzheimer's disease. The presence of some mild parkinsonian features will be accepted since ET is recognized to be associated with overlap symptoms of PD. The mild PD symptoms that will be tolerated for inclusion into the trial include resting tremor, bradykinesia, and rigidity.
  18. Presence of significant cognitive impairment as determined with a score ≤ 24 on the Mini Mental Status Examination (MMSE)
  19. History of immunocompromise, including patient who is HIV positive
  20. Known life-threatening systemic disease
  21. Patients with a history of seizures within the past year
  22. Patients with psychiatric illness that are not well controlled. Any presence of psychosis will be excluded. Patients with mood disorders including depression will be excluded if they have exhibited symptoms within 6 months while on medication. Patients who have been treated with transcranial magnetic stimulation or ECT will be excluded.
  23. Patients with risk factors for intraoperative or postoperative bleeding (platelet count less than 100,000 per cubic millimeter, PT > 14, PTT > 36 or INR > 1.3) or a documented coagulopathy
  24. Patients with brain tumors
  25. Any illness that in the investigator's opinion preclude participation in this study.
  26. Pregnancy or lactation.
  27. Legal incapacity or limited legal capacity.
  28. Patients who have had deep brain stimulation or a prior stereotactic ablation of the basal ganglia

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its identifier (NCT number): NCT01932463

Canada, Ontario
Sunnybrook Health Sciences Centre
Toronto, Ontario, Canada, M4N 3M5
Sponsors and Collaborators

Responsible Party: InSightec Identifier: NCT01932463     History of Changes
Other Study ID Numbers: MD002
First Posted: August 30, 2013    Key Record Dates
Last Update Posted: August 30, 2013
Last Verified: August 2013

Keywords provided by InSightec:
Essential Tremor
Medication-refractory Essential Tremor

Additional relevant MeSH terms:
Essential Tremor
Neurologic Manifestations
Nervous System Diseases
Signs and Symptoms
Movement Disorders
Central Nervous System Diseases