Supplementary Material for: Bilateral Radiofrequency Ventral Intermediate Thalamotomy for Essential Tremor

<b><i>Introduction:</i></b> With the advent of MR-guided focused ultrasound, the importance of the efficacy and safety of bilateral ventral intermediate (Vim) thalamotomy for essential tremor (ET) has increased. However, reports on bilateral Vim thalamotomy for ET remain scarce. <b><i>Methods:</i></b> To review the results and complications of bilateral Vim thalamotomy for the treatment of ET in the upper extremities, we retrospectively analyzed the patients with ET who underwent bilateral Vim thalamotomy with radiofrequency (RF) thermal coagulation. As bilateral simultaneous thalamotomy can cause surgical complications, thalamotomy was performed in stages. The interval between the first and second thalamotomies was 21.3 ± 14.7 months. We evaluated the efficacy using the Clinical Rating Scale for Tremor (CRST) before and after the first and second treatments, respectively. We also evaluated the complications before and after the first and second treatments, respectively. Moreover, we assessed the adverse events. <b><i>Results:</i></b> Seventeen patients were included in the study. The mean follow-up period following the second thalamotomy was 29.3 ± 15.0 months. The CRST part A + B scores were 34.9 ± 9.7, 20.8 ± 7.0, and 7.4 ± 6.8 before, following the first (40.4% improvement, <i>p</i> &lt; 0.0001) and second thalamotomies (78.6% improvement, <i>p</i> &lt; 0.0001), respectively. Nine patients presented with prolonged adverse events, including dysarthria, dysgeusia, dysphagia, tongue numbness, unsteady gait, and postural instability at the last available evaluation. All adverse events were mild and did not interfere with the patient’s daily activities. <b><i>Discussion/Conclusions:</i></b> Bilateral Vim thalamotomy with RF thermal coagulation was an effective treatment for ET in both upper extremities. Despite most possible complications being mild, additional studies with a larger sample size are required to ensure patient safety.