Background: Treatment options for patients with drug-resistant essential tremor (ET) are limited. Magnetic resonance-guided focused ultrasound surgery (MRgFUS) is an emerging technique to treat refractory ET. Objectives: To present MRgFUS as an alternative to radiofrequency (RF) thalamotomy or deep brain stimulation (DBS) for ET treatment. Methods: We retrospectively analyzed 59 patients who underwent unilateral surgery for drug-resistant ET. Treatments included RF thalamotomy (n = 17), DBS (n = 19), and MRgFUS (n = 23). The outcomes measured were tremor severity and treatment-related complications. Results: At 1 month postoperatively, 100% of RF thalamotomy patients, 89.5% of DBS patients, and 91.3% of MRgFUS patients exhibited absent/mild tremor (successful treatment); other patients exhibited partial relief. At 12 months postoperatively, treatment success for each procedure was observed in 70.6, 84.2, and 78.3% of patients, respectively. At 1 month postoperatively, treatment-related complications had occurred in 58.8, 5.3, and 13.0% of patients, respectively. At 12 months postoperatively, side effects persisted in 11.8, 21.1, and 4.4% of patients, respectively. No statistical differences in treatment success were observed between treatments or over time. Complication rates differed between treatment modalities (p < 0.01) and were lowest in the MRgFUS group. Conclusions: Patients with drug-resistant ET received equivalent results from RF thalamotomy, DBS, and MRgFUS. DBS and MRgFUS resulted in fewer treatment-related complications.

OBJECTIVE Recently, MR-guided focused ultrasound (MRgFUS) has emerged as an innovative treatment for numerous neurological disorders, including essential tremor, Parkinson's disease (PD), and some psychiatric disorders. Thus, clinical applications with this modality have been tried using various targets. The purpose of this study was to determine the feasibility, initial effectiveness, and potential side effects of unilateral MRgFUS pallidotomy for the treatment of parkinsonian dyskinesia. METHODS A prospective, nonrandomized, single-arm clinical trial was conducted between December 2013 and May 2016 at a single tertiary medical center. Ten patients with medication-refractory, dyskinesia-dominant PD were enrolled. Participants underwent unilateral MRgFUS pallidotomy using the Exablate 4000 device (InSightec) after providing written informed consent. Patients were serially evaluated for motor improvement, neuropsychological effects, and adverse events according to the 1-year follow-up protocol. Primary measures included the changes in the Unified Parkinson's Disease Rating Scale (UPDRS) and Unified Dyskinesia Rating Scale (UDysRS) scores from baseline to 1 week, 1 month, 3 months, 6 months, and 1 year. Secondary measures consisted of neuropsychological batteries and quality of life questionnaire (SF-36). Technical failure and safety issues were also carefully assessed by monitoring all events during the study period. RESULTS Unilateral MRgFUS pallidotomy was successfully performed in 8 of 10 patients (80%), and patients were followed up for more than 6 months. Clinical outcomes showed significant improvements of 32.2% in the "medication-off" UPDRS part III score (p = 0.018) and 52.7% in UDysRS (p = 0.017) at the 6-month follow-up, as well as 39.1% (p = 0.046) and 42.7% (p = 0.046) at the 1-year follow-up, respectively. These results were accompanied by improvement in quality of life. Among 8 cases, 1 patient suffered an unusual side effect of sonication; however, no patient experienced persistent aftereffects. CONCLUSIONS In the present study, which marks the first Phase I pilot study of unilateral MRgFUS pallidotomy for parkinsonian dyskinesia, the authors demonstrated the efficacy of pallidal lesioning using MRgFUS and certain limitations that are unavoidably associated with incomplete thermal lesioning due to technical issues. Further investigation and long-term follow-up are necessary to validate the use of MRgFUS in clinical practice. Clinical trial registration no.: NCT02003248 (clinicaltrials.gov).

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ABIs show favorable functional outcomes and long-term safety in nontumor deaf patients with limited treatment options. Collectively, our data indicate that ABIs represent an important treatment option for SNHL.