Simultaneous Bilateral Radiofrequency Thalamotomy for Medication-Refractory Essential Tremor
Phase: NA
Conditions: Essential Tremor
Sponsor: Tokyo Women's Medical University

Study Protocol 
Official Title: Simultaneous Bilateral Radiofrequency Thalamotomy Targeting the Ventral 
Intermediate Nucleus for Medication-Refractory Essential Tremor 
NCT Number: [Pending NCT Number] 
Document Date: July 03, 2025 
 
Title: Simultaneous Bilateral Radiofrequency Thalamotomy Targeting the Ventral 
Intermediate Nucleus for Medication-Refractory Essential Tremor 
Version: 5.1 
Date: July 03, 2025 
Principal Investigator: Shiro Horisawa, MD, PhD 
Affiliation: Department of Neurosurgery, Tokyo Women's Medical University 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

1. Background and Objective 
Essential tremor (ET) is a common movement disorder that significantly affects daily 
function. This study investigates the safety and efficacy of simultaneous bilateral 
radiofrequency (RF) thalamotomy targeting the ventral intermediate nucleus (Vim) of the 
thalamus. 
 
2. Study Design 
Single-arm, open-label interventional study with 5 participants, conducted from April 2025 
to September 2026 at Tokyo Women's Medical University. 
 
3. Eligibility Criteria 
Inclusion: Aged 20–70, ET diagnosis, medication-refractory, MMSE ≥27, MRI-compatible, 
consented. 
Exclusion: Bleeding tendency, MRI contraindications, intracranial lesions, pregnancy, or 
otherwise deemed inappropriate. 
 
4. Intervention 
Simultaneous bilateral RF thalamotomy under local anesthesia. Treatment starts on the 
dominant hand's contralateral side. Intraoperative MRI will confirm safety before 
proceeding to the second side. If complications arise, unilateral treatment only. 
 
5. Evaluation Schedule 
Pre- and post-operative assessments at baseline, 1, 3, and 6 months using CRST, QUEST, 
SARA, BDI, BAI, AES, MMSE, and MRI. 
 
6. Outcomes 
Primary: Change in CRST score from baseline to 6 months. 
Secondary: Changes in QUEST, SARA, mood scales, MRI lesion evaluation, adverse events. 
 
7. Statistical Analysis 

Wilcoxon signed-rank test for pre-post CRST score comparison. Missing data will be 
excluded. 
 
8. Adverse Events 
Expected: Intracranial hemorrhage <1%, dysarthria 10%, dysphagia 5%, numbness 5%, 
transient ataxia 5%. 
 
9. Ethics 
IRB approval obtained. Written consent required. Compliance with the Declaration of 
Helsinki. 
 
10. Conflict of Interest 
Managed under institutional COI policy. 
 
11. Publication and Data Sharing 
Results to be published. Data sharing TBD.