Unilateral gamma knife thalamotomy for tremor safety and efficacy in multimodal assessment: a prospective case-control study with two-year follow-up

Abstract

Introduction. Unilateral gamma knife thalamotomy (GKT) is a treatment option for pharmacoresistant tremor of various aetiologies. There have been to date no randomised controlled trials performed to assess its safety and efficacy. Our aim was to summarise a two-year multimodal observation of patients with tremor caused by Parkinson's Disease (PD) or essential tremor (ET).Material and methods. 23 patients with PD (n = 12) or ET (n = 11) were included. They underwent assessments before, V0 (n = 23), and 12 months, V12 (n = 23), and 24 months, V24 (n = 15), after unilateral GKT. Patients were assessed with psychological tests and acoustic voice analysis. Tremor assessment was performed with a digitising table using the Fahn-Tolosa-Marin rating scale (FTMRS). The Unified Parkinson's Disease rating scale part III (UPDRS-III) was also used in the PD group. Gait and balance was assessed using clinical tests, stabilometric platform, and treadmill. Results.No side effects were observed in a two-year follow-up. There was no notable deterioration observed in the patients' psychological evaluation, speech, or assessment of gait and balance. The scores were significantly lower (p = 0.01) in parts A and B of FTMRS one year after GKT. In post hoc analysis, the scores did not differ significantly between V0 and V24. In FTMRS part C (activities of daily living), no significant change was observed. There was no significant difference in total UPDRS part III score or in score of UPDRS part III domains 3 and 4 ('tremor at rest' and 'action and postural tremor of hands') between measurements. Conclusions.UGKT may be a safe treatment modality if performed in an experienced centre. Tremor reduction may diminish over time, and UGKT did not lead to cognitive, gait or speech deterioration in a long-term observation.

Thalamotomy for tremor: is it worth it?

“…It is reasonable to assume even better treatment durability today, given the advances in DBS technology, such as electrodes with segmented contacts, electrodes capable of sensing local field potentials, and modelling software that visualises www.journals.viamedica.pl/neurologia_neurochirurgia_polska Philip W. Tipton, Thalamotomy for tremor? [3]. Pair-wise comparison of tremorometry showed significant differences in several metrics not including peak-to-peak amplitude, which is likely to be the most clinically relevant variable in action tremors.…”

“…The 2016 approval of magnetic resonance-guided focused ultrasound (FUS) to treat ET reinvigorated interest in thalamotomies. Elsewhere in this issue of NiNP, Figura et al report 2-year safety and efficacy data for GKT to treat a small cohort of patients with ET or TAPD [3]. Their study was prompted by the recent European Academy of Neurology/Movement Disorders Society guidelines, which do not recommend GKT as a therapy for PD due to a lack of evidence for efficacy [4].…”

“…Figura et al have assessed the long-term side effects following unilateral GKT, and observed no significant worsening of cognition, speech, or balance [3]. They conclude that this lesioning technique is safe when performed at an experienced centre.…”