Postmortem Analysis 35 Months after Magnetic Resonance-Guided Focused Ultrasound Thalamotomy for Essential Tremor.

Background: Magnetic resonance-guided focused ultrasound (MRgFUS) thalamotomy is an emerging, non-invasive treatment for essential tremor (ET). However, postmortem data on the long-term neuropathological effects are limited.

Case report: An 86-year-old man with refractory ET underwent MRgFUS thalamotomy. Tremor improved by 95% and remained controlled until his death 35 months later. Postmortem MRI and neuropathologic analysis showed localized disruption of the dentatorubrothalamic tract and demyelination near the treatment site with preserved neuronal integrity.

Discussion: This is the first postmortem analysis of MRgFUS thalamotomy 35 months after procedure. Findings confirm sustained tremor relief associated with selective demyelination. The lesion remained well-defined without expansion, supporting MRgFUS as a precise and safe treatment for ET.

Highlights: This paper presents the first long-term (35-month) postmortem analysis of MRgFUS thalamotomy demonstrating sustained clinical efficacy. Postmortem MRI confirmed that the lesion remained localized to the original thalamotomy site, with focal disruption of the dentatorubrothalamic tract. Neuropathological examination revealed selective demyelination in the posterior thalamus near the treatment site, without evidence of neuronal loss. These findings support the long-term safety, precision, and durability of MRgFUS as a non-invasive therapeutic option for essential tremor.