Bond AE, et al. - Safety and efficacy of focused ultrasound thalamotomy for patients with medication-refractory, tremor-dominant Parkinson disease (TDPD) at 12-month follow-up were assessed. For patients with TDPD, focused ultrasound thalamotomy showed improvements in medication-refractory tremor by Clinical Rating Scale for Tremor (CRST) assessments, even in the setting of a placebo response.

• Fifty-three patients consented to be screened among the 326 patients identified from an in-house database.
• For this study, 26 patients were ineligible.
• From October 18, 2012, to January 8, 2015, 27 patients were randomized (2:1) to FUS thalamotomy or a sham procedure at 2 centers.
• Withdrawal (8 persons [31%]), and not being medication refractory (8 persons [31%]) were the most common reasons for disqualification.
• The researchers analyzed data using intention-to-treat analysis, and assessments were double-blinded through the primary outcome.
• They randomized 20 patients to unilateral FUS thalamotomy, and 7 to sham procedure.
• After unblinding, the sham group was offered open-label treatment.
• Safety and difference in improvement between groups at 3 months in the on-medication treated hand tremor subscore from the Clinical Rating Scale for Tremor (CRST) were the predefined primary outcomes.
• Descriptive results of Unified Parkinson’s Disease Rating Scale (UPDRS) scores and quality of life measures were included as secondary outcomes.

• Twenty-six (96%) were male among the 27 patients, and the median age was 67.8 years (interquartile range [IQR], 62.1-73.8 years).
• Following FUS thalamotomy, on-medication median tremor scores improved 62% (IQR, 22%-79%) from a baseline of 17 points (IQR, 10.5-27.5) and after sham procedures, 22% (IQR, -11% to 29%) from a baseline of 23 points (IQR, 14.0-27.0).
• The between-group difference was significant (Wilcoxon P=.04).
• After FUS thalamotomy, on-medication median UPDRS motor scores improved 8 points (IQR, 0.5-11.0) from a baseline of 23 points (IQR, 15.5-34.0) and 1 point (IQR, -5.0 to 9.0) from a baseline of 25 points (IQR, 15.0-33.0) following sham procedures.
• Heating of the internal capsule resulted in 2 cases (8%) of mild hemiparesis, early in the study, which improved and prompted monitoring of an additional axis during magnetic resonance thermometry.
• Orofacial paresthesia (4 events [20%]), finger paresthesia (1 event [5%]), and ataxia (1 event [5%]) were other persistent adverse events.