Optimization of VIM Targeting in Essential Tremor Surgery

Not Applicable

Completed

• Conditions: Essential Tremor
• Interventions: Procedure: Opti-VIM targeting in DBS surgery

• Registration Number: NCT03760406
• Lead Sponsor: University Hospital, Bordeaux

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.

Study Timeline

• Study First Submitted: 2018-11-26
• Study First Submitted QC: 2018-11-29
• Study First Posted: 2018-11-30
• Study Start: 2019-03-18
• Primary Completion: 2023-08-29
• Study Completion: 2023-08-29
• Status Verified: 2025-02
• Last Update Submitted: 2025-02-21
• Last Update Posted: 2025-02-25

Recruitment & Eligibility

• Status: COMPLETED
• Sex: All
• Target Recruitment: 22

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

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: SINGLE_GROUP

Arm && Interventions

Group	Intervention	Description
Severe essential tremor treated by DBS	Opti-VIM targeting in DBS surgery	-

Primary Outcome Measures

Name	Time	Method
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 Outcome Measures

Name	Time	Method
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
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
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.

Trial Locations

Locations (2)

CHU de Bordeaux; 🇫🇷 Bordeaux, France

Hospices Civils de Lyon; 🇫🇷 Bron, France