Hybrid surgery of ventral intermediate nucleus thalamotomy using magnetic resonance-guided focus ultrasound and modulation by deep brain stimulation controls bilateral essential tremor

Objective: Medication-resistant essential tremor requires surgical treatment. Deep brain stimulation to the thalamic ventral intermediate nucleus is an established procedure to diminish tremors. Tremor on both sides needs dual deep brain stimulation implantation. Nowadays, magnetic resonance-guided focus ultrasound is broaden to treat essential tremor. However, the safety of magnetic resonance-guided focus ultrasound against dual ventral intermediate is still under discussion, since bilateral thalamotomy causes speech disturbance or ataxia. Patient and Methods: A 66-year-old right-handed man had medication-resistant essential tremor at bilateral upper extremities superior to the left arm. A treatment of magnetic resonance-guided focus ultrasound was performed by using the ExAblate transcranial system against the left ventral intermediate. One year after magnetic resonance-guided focus ultrasound treatment, the stereotactic implantation of a deep brain stimulation electrode into the right ventral intermediate was done. Results: Clinical rating scale for tremor in the right arm was reduced from 12 to 0 points by magnetic resonance-guided focus ultrasound against the left ventral intermediate. The clinical rating scale for tremor in the left arm was reduced from 23 to 1 point by deep brain stimulation to the right ventral intermediate. Conclusion: Hybrid surgery of magnetic resonance-guided focus ultrasound and deep brain stimulation refined bilateral essential tremor, without any neurological deficiencies. This combined surgery would be useful to manage medication-resistant bilateral essential tremor patients who are carrying some difficulties to introduce deep brain stimulation on the bilateral side.