Focused Ultrasound Thalamotomy for Essential Tremor in Octogenarians

Introduction: Essential tremor (ET) is common and disabling in older adults. Many patients aged ≥80 years are ineligible for deep brain stimulation (DBS) due to medical comorbidities. Data on non-invasive alternatives such as magnetic resonance-guided high-intensity focused ultrasound (MRgHIFU) remain limited in this population. This study aimed to evaluate the safety and efficacy of unilateral MRgHIFU thalamotomy targeting the ventral intermediate nucleus (VIM) in patients aged ≥80 years with ET.

Methods: This retrospective multicenter cohort study included consecutive patients aged ≥80 years with medically refractory ET treated with unilateral MRgHIFU VIM thalamotomy between 2016 and 2023 at five academic neurosurgical centers. All patients met skull density ratio criteria and underwent standardized targeting. Clinical assessments were conducted at baseline, immediately post-treatment, and at 3-month follow-up. The primary outcome was change in tremor severity using the Tremor Research Group Essential Tremor Rating Assessment Scale (TETRAS). Secondary outcomes included Clinical Rating Scale for Tremor (CRST), Dynamic Gait Index (DGI), patient-reported tremor relief, and adverse events.

Results: A total of 129 patients (mean age 83.9 years) were included. At 3 months, the mean TETRAS score improved by 9.2 points (p < 0.001). CRST scores also showed significant improvement. The average patient-reported tremor relief was 81%. Adverse events were mild and transient, with a 1.6% rate of non-surgical complications. Subgroup analysis comparing patients aged 80–84 versus ≥85 years showed no significant differences in treatment response. Gait outcomes improved modestly but were not significant in the ≥85 group.

Conclusion: Unilateral MRgHIFU thalamotomy is a safe and effective non-invasive treatment for ET in patients aged ≥80 years. It results in significant improvements in tremor and disability with a low complication rate. These findings support its consideration for elderly patients ineligible for invasive procedures and highlight the importance of age-specific metrics in neuromodulation outcomes research.