Delayed clinical response to focused ultrasound thalamotomy in essential tremor in a patient with suboptimal skull density ratio - A case report.

Background: Magnetic resonance imaging-guided focused ultrasound (MRgFUS) thalamotomy offers incisionless treatment for essential tremor or tremor-dominant Parkinson's disease, gaining acceptance as an alternative to deep brain stimulation. Compared to other methods, it offers real-time efficacy assessment without ionizing radiation.

Case description: A 63-year-old male underwent MRgFUS, initially yielding subtle results due to skull limitations. However, significant tremor relief emerged 6 hours post-procedure, sustained for 5 days. Imaging confirmed thalamotomy effect. A second treatment was delivered at day five for longevity.

Conclusion: For patients with challenging skull characteristics and initial suboptimal outcomes, staged procedures may be considered, with potential delayed benefits and the need for lesion expansion for long-term relief.