Safety and Effectiveness of Unilateral MR-Guided Focused Ultrasound Thalamotomy for Essential Tremor

A Multicenter, Non-Randomized Controlled Observational Study on the Safety and Effectiveness of Unilateral MR-Guided Focused Ultrasound Thalamotomy for Essential Tremor

Essential tremor (ET) is one of the most common movement disorders, significantly impacting patients' quality of life. Many patients do not respond well to medication or cannot tolerate side effects, leaving limited treatment options. Magnetic Resonance-guided Focused Ultrasound (MRgFUS) is a noninvasive, targeted therapy that offers a promising alternative to surgical procedures such as deep brain stimulation.

This study is a multicenter, non-randomized controlled observational study designed to evaluate the safety and effectiveness of unilateral MRgFUS thalamotomy targeting the ventral intermediate nucleus (VIM) in patients with medication-refractory essential tremor. Participants will be divided into two groups based on clinical evaluation and patient preference: the treatment group receiving MRgFUS and the control group receiving standard medical therapy. Both groups will undergo regular follow-up for one year.

The primary outcome is improvement in tremor severity as measured by the Fahn-Tolosa-Marin Tremor Rating Scale and the Clinical Rating Scale for Tremor. Secondary outcomes include quality of life, cognitive and emotional status, and treatment-related adverse events.

Eligible participants are adults aged 22 years or older who have a confirmed diagnosis of essential tremor and are significantly impaired despite medication. The goal is to assess whether MRgFUS provides sustained tremor relief and improves quality of life in comparison to standard care, while maintaining an acceptable safety profile.

Essential tremor (ET) is a progressive neurological disorder characterized primarily by action tremor affecting the upper limbs, head, or voice. Although ET is commonly treated with medications such as beta-blockers and anticonvulsants, a significant proportion of patients are either refractory to or intolerant of pharmacologic therapies. For these patients, surgical interventions such as deep brain stimulation (DBS) or thalamotomy may be considered. However, these procedures are invasive and associated with considerable risks and costs.

Magnetic resonance-guided focused ultrasound (MRgFUS) is a novel, non-invasive technology that enables precise thermal ablation of brain targets, such as the ventral intermediate nucleus (VIM) of the thalamus, under real-time MRI guidance. MRgFUS offers advantages such as immediate effect, no need for implants, and lower complication rates.

This multicenter, non-randomized, controlled observational study aims to evaluate the real-world effectiveness and safety of unilateral MRgFUS VIM thalamotomy in patients with medication-refractory ET. Patients will be allocated into treatment or control groups based on clinical judgment and patient preference. The study will focus on assessing improvements in tremor severity, quality of life, and treatment safety over a 12-month follow-up period. The findings will provide evidence on the utility of MRgFUS as a non-invasive therapeutic option and help inform future clinical decision-making for ET management.

Inclusion Criteria:

• Age ≥ 22 years
• Diagnosis of essential tremor confirmed by clinical criteria
• Medication-refractory tremor with significant functional impairment
• Ability to provide informed consent
• Willingness to undergo follow-up assessments for 12 months

Exclusion Criteria:

• History of other neurological disorders (e.g., Parkinson's disease)
• Presence of unstable medical conditions (e.g., uncontrolled hypertension)
• Contraindications to MRI (e.g., implanted metal devices)
• Severe cognitive impairment or psychiatric illness
• Pregnancy or breastfeeding