Magnetic Resonance Image-Guided Focused Ultrasound Ventral Intermediate Nucleus Thalamotomy with Indwelling Globus Pallidus Internus Deep Brain Stimulation Electrodes: A Case Report.

Deep brain stimulation (DBS) is the gold-standard surgical treatment for essential tremor (ET) and tremor-predominant Parkinson's disease (TdPD). However, despite appropriate electrode placement and programming, patients may develop tremor recurrence due to disease progression. MRI-guided focused ultrasound (MRgFUS) thalamotomy is an alternative treatment to DBS and has been shown to yield durable tremor control in both ET and TdPD patients. However, MRgFUS thalamotomy in a patient with indwelling DBS electrodes has not been previously reported. We present the case of a 77-year-old male with progressive TdPD who underwent bilateral globus pallidus internus (GPi) DBS with subsequent right unilateral ventral intermediate nucleus thalamotomy 23 months after DBS due to progressive tremor recurrence. At 6-month follow-up, his tremor has completely resolved. This is the first report of MRgFUS thalamotomy for recurrent tremor with indwelling DBS electrodes. We found that MRgFUS thalamotomy as salvage therapy with implanted GPi DBS electrodes is both safe and effective. It represents a novel potential treatment paradigm for TdPD patients with persistent tremor despite otherwise effective GPi DBS.