A Feasibility Study to Evaluate Safety and Initial Effectiveness of ExAblate Transcranial MR Guided Focused Ultrasound for Unilateral Thalamotomy in the Treatment of Essential Tremor
Overview
- Phase
- Phase 1
- Intervention
- Not specified
- Conditions
- Essential Tremor
- Sponsor
- InSightec
- Enrollment
- 15
- Locations
- 1
- Primary Endpoint
- Device or procedure related Adverse Events reported
- Status
- Completed
- Last Updated
- 12 years ago
Overview
Brief Summary
The purpose of this study is to evaluate the safety and initial effectiveness of MRI-guided focused ultrasound thermal ablation of a designated area in the brain of patients suffering from medication-refractory Essential Tremor, using the ExAblate transcranial system.
The ExAblate system is a medical device that involves a focused ultrasound system and an MRI scanner. ExAblate delivers a pulse of focused ultrasound energy, or sonication, to the targeted tissue. In this particular study the targeted tissue is a unilateral thermal lesion created in the ventralis intermedius nucleus of the thalamus.
The treatment begins with a series of standard diagnostic MR images to identify the location and shape of tumor to be treated. The ExAblate computer uses the physician's designation of the target volume to plan the best way to cover the target volume with small spots called "sonications". These treatment spots are cylinder shaped. Their size depends on sonication power and duration. During the treatment, a specific MR scan, which can be processed to identify changes in tissue temperature, provides a thermal map of the treatment volume to confirm the therapeutic effect. The thermal map is used to monitor the treatment in progress, and confirm that the ablation is proceeding according to plan, thus closing the therapy loop.
The ExAblate transcranial operates a helmet-shaped transducer (currently utilizing 1000-element phased array transducer) positioned above the subject head. The ExAblate transcranial system also includes means to immobilize the subject head, cool the interface water, and software for CT analysis and phase correction computation.
The ExAblate transcranial system is an experimental device and is being investigated in this study.
Investigators
Eligibility Criteria
Inclusion Criteria
- •Men and women, between 18 and 80 years, inclusive
- •Patients who are able and willing to give consent and able to attend all study visits
- •A diagnosis of ET as confirmed from clinical history and examination by a movement disorder neurologist
- •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.
- •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.
- •Able to communicate sensations during the ExAblate MRgFUS treatment
- •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.
- •Stable doses of all medications for 30 days prior to study entry and for the duration of the study.
- •May have bilateral appendicular tremor
- •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: \[speaking, feeding other than liquids, bringing liquids to mouth, hygiene, dressing, writing, working, and social activities\])
Exclusion Criteria
- •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
- •Patients exhibiting any behavior(s) consistent with ethanol or substance abuse as defined by the criteria outlined in the DSM-IV as manifested by one (or more) of the following occurring within a 12 month period: Recurrent substance use resulting in a failure to fulfill major role obligations at work, school, or home (such as repeated absences or poor work performance related to substance use; substance-related absences, suspensions, or expulsions from school; or neglect of children or household).
- •Recurrent substance use in situations in which it is physically hazardous (such as driving an automobile or operating a machine when impaired by substance use) Recurrent substance-related legal problems (such as arrests for substance related disorderly conduct) Continued substance use despite having persistent or recurrent social or interpersonal problems caused or exacerbated by the effects of the substance (for example, arguments with spouse about consequences of intoxication and physical fights).
- •Severe hypertension (diastolic BP \> 100 on medication)
- •Patients with standard contraindications for MR imaging such as non-MRI compatible implanted metallic devices including cardiac pacemakers, size limitations, etc.
- •Known intolerance or allergies to the MRI contrast agent (e.g. Gadolinium or Magnevist) including advanced kidney disease
- •Severely impaired renal function (estimated glomerular filtration rate \< 45ml/min/1.73 m2) or receiving dialysis
- •History of abnormal bleeding and/or coagulopathy
- •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
Outcomes
Primary Outcomes
Device or procedure related Adverse Events reported
Time Frame: 3 Months
Safety of the ExAblate transcranial treatment will be determined by an evaluation of the incidence and severity of device and procedure related complications from the first / treatment day visit through the 3-Months post-treatment time point. Alternative treatments resulting from post-surgical changes in neurological status will be reported.
Secondary Outcomes
- Tremor rating scales: the Clinical Rating Scale for Tremors(3 months)