Essential Tremor
Conditions
Keywords
Essential Tremor, Deep brain stimulation, Ventro-intermediate nucleus of the thalamus, Targeting, Asleep surgery
Brief summary
Deep brain stimulation (DBS) for essential tremor is based on the intermedius ventralis nucleus of the thalamus (VIM) stimulation. This structure is however very difficult to target, as it remains invisible on imaging. The current procedure based on awake surgery with clinical and electrophysiological testings has several limitations that lead us to develop a probabilistic model to locate precisely the target. This study aims to show that asleep DBS surgery based on this new targeting method leads to at least the same clinical results than the classical procedure.
Detailed description
The intermedius ventralis nucleus of the thalamus (VIM), which represents the target for deep brain stimulation (DBS) in essential tremor, still remains invisible on 1,5 tesla MRI (the only magnetic field available for stereotactic surgery). The target coordinates currently used are based on stereotactic atlases or mean coordinates from retrospective series. They are so imprecise that intra-operative clinical testing and micro-electrode recordings are mandatory to locate the exact position of the VIM. This procedure is long lasting, requires that the patient is awake, and increases the risk of intracerebral haemorrhage and nosocomial infections. Furthermore, some patients are not improved despite a DBS lead implanted in the electrophysiologically and clinically defined target. To overcome these limitations, investigators developed a probabilistic model based on data extracted from imaging of patients with particularly good outcomes after DBS surgery. This machine-learning model allows calculating to coordinates of the VIM according to the position of radio-anatomical landmarks with a mean precision of 1,65mm. The aim of this study is to validate this new targeting method on a prospective cohort of patients. DBS surgery will be performed under general anaesthesia, without intra-operative clinical and electrophysiological testing, with a surgical robot and under CT-scan guidance (O-Arm ©). Neurostimulation device programming will be performed as usual. Patients' tremor and quality of life will be evaluated pre and post-operatively at 3 months, according to the Fahn-Tolosa-Marin (FTM) scale and with an accelerometry recording (for tremor) and with the mPDQ-39 scale for quality of life. Surgical complications and side effects related to neurostimulation will be gathered all along the follow-up.
Interventions
PROCEDUREOpti-VIM targeting in DBS surgery
DBS surgery will be performed under general anaesthesia, without intra-operative clinical and electrophysiological testing, with a surgical robot and under CT-scan guidance (O-Arm ©). The VIM coordinates will be calculated with the probabilistic model that have been developed.
Sponsors
University Hospital, Bordeaux
Study design
Allocation
NA
Intervention model
SINGLE_GROUP
Primary purpose
BASIC_SCIENCE
Masking
NONE
Eligibility
Sex/Gender
ALL
Age
18 Years to 75 Years
Healthy volunteers
No
Inclusion criteria
* Severe essential tremor despite the optimal medical management * Age between 18 and 75 years * Normal MRI scan * Mattis Dementia Rating Scale (MDRS) score ≥ 130 * Affiliation to the social security * Signed informed consent
Exclusion criteria
* Depression (Beck Depression Inventory scale \> 20) * Contra-indication to surgery or general anesthesia * Cerebral atrophy on MRI scan * Pregnant or breastfeeding women
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Change of Fahn-Tolosa-Marin (FTM) scale score | Before and 3 month after DBS surgery | Scale global range : min=0 / max=160 Higher values represent worse tremor |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Accelerometry recordings : spectral analysis | Before and 3 month after DBS surgery | Accelerometry recordings at the pre-inclusion visit and at 3 months after surgery in ON and OFF-stimulation conditions with spectral analysis. |
| Accelerometry recordings : calculation of the total accelerometry power | Before and 3 month after DBS surgery | Accelerometry recordings at the pre-inclusion visit and at 3 months after surgery in ON and OFF-stimulation conditions with calculation of the total accelerometry power. |
| Surgical complications | Up to 3 month after DBS surgery | Onset of infection, hematoma or seizure |
| Device complications and dysfunction | Up to 3 month after DBS surgery | rupture or displacement of electrode, pain at the stimulation box implantation site or along the subcutaneous cable if they require further intervention, infection. |
| Neurostimulation-related side effects | Up to 3 month after DBS surgery | Onset of dysarthria and ataxia assessed by the items 1 to 4 of the Scale for Assessment and Rating of Ataxia (SARA), ataxia assessed by a posturometry analysis, paresthesia, muscular contractions |
| Quality of life: change of modified Parkinson's Disease Questionnaire-39 (mPDQ-39) scale score | Before and 3 month after DBS surgery | Adaptation of Parkinson's Disease Questionnaire-39 to essential tremor Scale global range : min=0 / max=156 Higher values represent worse Quality of life |
| Coordinates of active contacts | 3 month after DBS surgery | Coordinates of active contacts (i.e; the contact with the best effect on tremor without side effects) These coordinates (x, y, z) are obtained by merging the images of the 3-month postoperative scanner with the images of the preoperative MRI. |
Countries
France
Contacts
STUDY_CHAIRAntoine BENARD, MD
USMR CHU de Bordeaux
Outcome results
None listed