Focused Ultrasound Thalamotomy in Tremor Dominant Parkinson's Disease: Long-Term Results

BACKGROUND MRI-guided focused ultrasound (FUS) has established short-term efficacy in tremor relief. OBJECTIVE We report our long-term experience of treating tremor with unilateral FUS unilateral VIM-thalamotomy in tremor dominant Parkinson's disease (TDPD) patients. METHODS We report outcome of FUS thalamotomy in TDPD patients with 1-5 years of follow-up. OUTCOMES tremor reduction assessed with Clinical Rating Scale for Tremor (CRST) and Unified Parkinson's Disease Rating Scale (UPDRS part III) overall and in the treated hemibody and safety. RESULTS Twenty-six TDPD patients completed 1-5 years of follow-up (median follow-up 36 months, range 12-60 months). Median age was 60 years (range 46-79), with median disease duration of 6 years (range 2-16). Immediately, treatment resulted in 100%improvement in tremor in the treated arm in 23 patients and 90%improvement in 3 patients. In 15 patients with leg tremor, 2 patients with chin tremor and 1 patient with head tremor, tremor was significantly improved. Up to 5 years, median CRST score, median UPDRS score, overall and in treated hemibody, decreased significantly as compared with baseline (p <  0.0001). In 2 patients tremor returned completely and in 8 patients there was partial return of tremor. Adverse events were mild and resolved within 3 months. At baseline 4 patients were not receiving any medication vs. 3 at last follow-up and 15 were not taking levodopa vs.9 at last follow-up. CONCLUSION Unilateral FUS VIM-thalamotomy in TDPD patients was effective and safe and provided long-term tremor relief in most patients. FUS thalamotomy for tremor may delay initiation of levodopa treatment.