Objective: To study the effect of MR-guided focused ultrasound (MRgFUS) targeting the ventral intermediate nucleus of the thalamus (VIM) after a failed ipsilateral Gamma Knife radiosurgery (GKRS) thalamotomy.
Background: GKRS and MRgFUS are two non-invasive methods proposed in cases of severe drug-resistant/intolerant essential tremor (ET).
Method: Case report
Results: A 67-year-old left-handed female patient with disabling medically-refractory ET underwent successful right MRgFUS VIM thalamotomy after a failed GKRS ipsilateral thalamotomy performed three years earlier. The GKRS had a partial effect on her postural tremor with no significant impact in her kinetic tremor and no improvement in her quality of life. The GKRS lesion was located within the VIM in the 1-year- and 3-year-post GKRS MRI. However, not all fibers of the dentatorubrothalamic tract (DRTT) were interrupted on the 3-year-post GKRS MRI. In contrast the MRgFUS procedure induced an immediate and excellent reduction in both postural and kinetic tremor components. Six-months post-MRgFUS, the beneficial effect was sustained with a 62% improvement of her left-hand tremor score, a significant improvement in all daily life activities and slight side effects. The MRgFUS-induced lesion was more medial and extended more posteriorly and inferiorly than the GKRS-induced lesion. The MRgFUS-induced lesion interrupted all the remaining fibers of the DRTT.
Conclusion: In this patient, GKRS failure could be secondary to GKRS hyporesponse leading to a small lesion within the VIM with insufficient interruption of the DRTT. MRgFUS has a better target accuracy because of its acute physical thermocoagulation effect and immediate clinical effectiveness which allow “test lesions” and procedural evaluations. MRgFUS VIM thalamotomy can be safely and successfully proposed after an unsuccessful ipsilateral GKRS thalamotomy.
To cite this abstract in AMA style:
V. Fleury, DR. Romascano, OL. Lorton, CT. Tuleasca, SCC. Catalano Chiuve, RS. Salomir, ML. Levivier, SM. Momjian, PRB. Burkhard. Success of MRI-guided focused ultrasound thalamotomy after failure of Gamma Knife radiosurgery for essential tremor [abstract]. Mov Disord. 2023; 38 (suppl 1). https://www.mdsabstracts.org/abstract/success-of-mri-guided-focused-ultrasound-thalamotomy-after-failure-of-gamma-knife-radiosurgery-for-essential-tremor/. Accessed June 14, 2025.« Back to 2023 International Congress
MDS Abstracts - https://www.mdsabstracts.org/abstract/success-of-mri-guided-focused-ultrasound-thalamotomy-after-failure-of-gamma-knife-radiosurgery-for-essential-tremor/