Focused ultrasound thalamotomy for essential tremor in octogenarians.

OBJECTIVE

Essential tremor (ET) is common and disabling in older adults. Many patients aged ≥ 80 years are ineligible for deep brain stimulation due to medical comorbidities. Data on noninvasive alternatives, such as MR-guided high-intensity focused ultrasound (MRgHIFU), remain limited in this population. The aim of this study was to evaluate the safety and efficacy of unilateral MRgHIFU thalamotomy targeting the ventral intermediate nucleus (VIM) for the treatment of ET in patients ≥ 80 years of age.

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 posttreatment, and at the 3-month follow-up. The primary outcome was change in tremor severity assessed by using the Tremor Research Group Essential Tremor Rating Assessment Scale (TETRAS). Secondary outcomes included the Clinical Rating Scale for Tremor (CRST) score, Dynamic Gait Index score, patient-reported tremor relief, and adverse events.

RESULTS

One hundred twenty-nine patients (76 male, mean age 84 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 mean patient-reported tremor relief was 81%. Adverse events were mild and transient, with a 1.6% rate of nonsurgical adverse events. Subgroup analysis comparing patients 80-84 years versus those ≥ 85 years of age showed no significant differences in treatment response. Gait outcomes improved modestly but were not significant in the age ≥ 85 years group.

CONCLUSIONS

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