Repeat Ipsilateral Focused Ultrasound Thalamotomy after Tremor Recurrence: Safety, Efficacy, and Lesion Analysis

Background Magnetic resonance imaging (MRI)‐guided focused ultrasound (MRgFUS) thalamotomy provides durable tremor control for most patients with essential tremor (ET) and tremor‐dominant Parkinson's disease (TdPD), but tremor can recur. Objectives To evaluate the safety, efficacy, and lesion characteristics of repeat MRgFUS thalamotomy for tremor recurrence. Methods We retrospectively analyzed patients undergoing repeat ipsilateral MRgFUS thalamotomy. Clinical Rating Scale for Tremor‐Part A (CRST‐A) assessed tremor severity preoperatively and 1 day, 1 week, 1 month, 3 months, and 1 year after retreatment. Outcomes, side effects, lesion volumes and locations, and treatment parameters were compared with initial procedures and an institutional one‐time MRgFUS cohort (n = 535). Results Thirty patients (26 ET, 4 TdPD) underwent repeat thalamotomy with ≥3 months follow‐up. Mean CRST‐A improved from 5.37 preoperatively to 0.27 at day 1 (94.9% improvement), 2.00 (64.4%) at 3 months, and 2.50 (38.8%) at 1 year (all P ≤ 0.003 vs. baseline). Tremor recurred at similar rates after initial and repeat treatments. Repeat lesions were larger (526.3 vs. 414.1 mm 3 , P = 0.025) and shifted anteriorly (+1.2 mm, P = 0.003). Initial lesion volume in retreatment patients was similar to the one‐time cohort. Compared with initial treatments, patients more often experienced any side effect at 1 month ( P = 0.023) and had more side effects at 1 month ( P < 0.001) and 3 months ( P = 0.014) after repeat treatment. Patient satisfaction was high and 85% of patients would choose retreatment again. Conclusions Repeat ipsilateral MRgFUS thalamotomy restored tremor control after recurrence and achieved high patient satisfaction, despite increased side effects after repeat treatment and similar tremor progression rates after initial and repeat procedures.