Gamma Knife Thalamotomy for Essential Tremor: A Retrospective Analysis

Gamma knife versus linear accelerator thalamotomy for essential tremor and Parkinson's disease: A systematic review and meta-analysis

BACKGROUND

Tremor, either in patients with Essential Tremor (ET) or Parkinson's disease (PD), constitutes the most common movement disorder. Stereotactic radiosurgery using Gamma Knife (GK) and linear accelerator (LINAC) systems, is an effective, incisionless treatment modality for ET and PD. Although these technologies have been used clinically since the 1990's, most studies have focused on GK, and efficacy, safety and time to treatment effect (latency) of GK and LINAC have not been compared.

OBJECTIVE

We therefore aimed to conduct a systematic review with network meta-analysis examining efficacy, adverse events (AEs) and latency of GK and LINAC for treating tremor in ET and PD.

METHODS

We conducted a systematic review with network meta-analysis in accordance with PRISMA guidelines, using the Embase and PubMed databases. We included all primary GK/LINAC thalamotomy studies in ET/PD patients with at least 6 months of follow-up, reporting unilateral Fahn-Tolosa-Marin Tremor Scale (FTM-TRS) or Unified Parkinson's disease rating scale (UPDRS) scores pre-treatment/post-treatment and/or AEs and/or latency. The primary efficacy outcome was FTM-TRS Scale A or UPDRS Item 16 score reduction. AEs were presented as an estimated incidence, and latency as average time to first recorded clinical improvement in tremor.

RESULTS

Six studies of 311 patients and 2 studies of 60 patients met inclusion criteria for GK/LINAC efficacy comparison, respectively. Network meta-analysis showed similar tremor reduction between modalities (standardized mean difference between pre- and post-treatment scores: GK: -2.18 (95 % CI: -2.79, -1.57); LINAC: -2.13 (95 % CI: -5.13, 0.87). GK also had a higher absolute AE rate, while LINAC was associated with a greater latency period. There was no correlation between GK efficacy and AE rate.

CONCLUSIONS

Despite the relatively small sample sizes, these results demonstrate similar efficacy between GK and LINAC for ET and PD, with a trend toward higher efficacy but greater AE incidence and slower onset of tremor improvement in GK compared to LINAC.

Radiosurgical thalamotomy for the management of tremors: a systematic review and meta-analysis

Medical treatment for tremors may include beta-blockers, primidone, dopaminergic, and anticholinergic drugs but it frequently leads to pharmacoresistance. Therefore, surgical treatment gained relevance as an alternative for those patients.We aim to evaluate radiosurgical thalamotomy as an effective and safe alternative to manage tremors. Pubmed (MEDLINE), Embase, Web of Science, and the Cochrane Library databases were systematically searched for potential articles that evaluated radiosurgical thalamotomy for the management of tremor. Our analysis included 12 studies with 545 patients, 226 of whom were female. Of these, 64.6% of patients were diagnosed with essential tremor (ET), 34.6% with Parkinson's disease (PD), and 0.8% with both ET and PD. The FTM-TRS global score (MD -5.46; 95% CI [-10.44]-[-0.47]; I2 = 52%) and the drawing (MD -1.40; 95% CI [-2.03]-[-0.76]; I2 = 93%), drinking (MD -1.60; 95% CI [-1.82]-[-1.37]; I2 = 40%), and writing (MD -1.51; 95% CI [-1.89]-[-1.13]; I2 = 89%) grades showed significantly lower mean differences, favoring radiosurgical thalamotomy. A pooled proportion of 12% presented with tremor unchanged, while 38% presented with total elimination of tremor. Adverse events included: major paresis, minor paresis, dysarthria, and numbness. Thus, radiosurgical thalamotomy is a safe alternative for tremors resistant to medication, particularly in high-risk patients for RF or DBS procedures. The recommended dose of 130 to 150 Gy is effective and well-tolerated. However, randomized controlled trials (RCTs) are needed to understand the unpredictability of tissue response to radiation.

Efficacy and safety of stereotactic radiosurgery with gamma knife machine in patients with essential tremor: a systematic review and single-arm meta-analysis

Essential tremor (ET) is identified as the most prevalent movement disorder, primarily characterized by tremors in both upper extremities. The spectrum of surgical options for ET includes gamma knife radiosurgery (GKRS) and other stereotactic radiosurgery (SRS) modalities. Despite the limitations of these options, SRS is deemed an essential and indispensable approach. Our research aimed to assess the safety and efficacy of SRS, such as GKRS, on tremor control and the spectrum of associated adverse events in the treatment of ET, also focusing on long term outcomes of the procedure. We systematically conducted an extensive search across esteemed databases, which included PubMed, Cochrane Library, Embase, and Web of Science. We included studies involving individuals diagnosed with ET who had undergone GRKS treatment. A proportional rate was used to evaluate the outcomes in a 95% confidence interval. We included 12 studies comprising 414 patients. The treatment success rate with SRS was 86.6% (95% CI: 72.4-100%). Conversely, the overall failure rate was 13.4% (95% CI: 0.00 to 27.6%). Notably, post-procedure complications were observed in 9.7% of patients (95% CI: 5.8-13.6%). A meta-analysis of five studies revealed a statistically significant reduction of tremor from the FTM scale after treatment with GKRS (MD -2.1; 95% CI -2.5 to -1.6; p < 0.01; I² = 81%). A meta-analysis of eight studies revealed a statistically significant reduction in writing tremor from the FTM scale after treatment with GKRS (MD -1.7; 95% CI -2.3 to -1.2; p < 0.01; I² = 93%). A meta-analysis of six studies revealed a statistically significant reduction in drawing tremor from the FTM scale after treatment with GKRS (MD -1.9; 95% CI -2.5 to -1.4; p < 0.01; I² = 80%). Finally, a meta-analysis of three studies revealed a statistically significant reduction in drinking tremor from the FTM scale after treatment with GKRS (MD -1.6; 95% CI -1.9 to -1.3; p < 0.01; I² = 11%). Our findings show a high success rate and low failure of GKRS for ET. Thus, GKRS is a seemingly effective and safe option for managing these patients. The importance of this research lies in its contribution to the evolving landscape of radiosurgery, providing a robust basis for the clinical application of GKRS.

Research hotspots and frontiers of essential tremor from 2013 to 2023: a visualization analysis based on CiteSpace

BACKGROUND

ET, one of the most prevalent neurological disorders, presents a significant challenge in terms of disability. Despite the growing focus on ET in recent years, comprehensive bibliometric analysis has been lacking.

METHODS

This study delves into essential tremor research covering the period from 2013 to 2023, utilizing the Web of Science (WOS) database. Employing CiteSpace for quantitative analysis, it examines an array of metrics including annual publication trends, contributions from countries and institutions, authorship patterns, key terminologies, and patterns of reference co-citation. The primary objective is to use CiteSpace for a detailed visual exploration of the literature over the last decade, pinpointing the evolving landscape and key areas of focus in essential tremor research, and thus providing a foundation for future investigative endeavors.

RESULTS

There were 2,224 literary works included in all. The amount of published works has been steadily rising in recent years. Of them, the majority originate from the United States, Louis, Elan D. is the publisher of the most publications (161 articles), and Movement Disorders is the journal that receives the most citations. The key words contribution and co-cited literatures suggest that the main research hotspots in recent years are the physiological and pathological mechanism of essential tremor, the determination of optimal targets for deep brain stimulation (DBS) and surgery transcranial magnetic resonance-guided focused ultrasound (MRgFUS) in the surgical management of essential tremor and the innovative research of botulinum toxin administration method.

Stereotactic radiosurgery in the treatment of essential tremor - a systematic review

Introduction

Essential tremor (ET) is the most common movement disorder in adults, with an estimated incidence of up to 1% of the population and 5% of people older than 65 years of age. ET is manifested primarily by bilateral postural and kinetic tremor of the upper limbs with or without neurological symptoms and cognitive deficits. ET disrupts daily tasks and significantly lowers quality of life. Currently available medications alone are often insufficient to control severe symptoms. Several surgical treatment options are available, including stereotactic radiosurgery (SRS)-a minimally invasive treatment option aimed at relieving and controlling tremors.

Methods

We conducted a systematic review of the scientific literature on the use of SRS in the treatment of ET using PubMed, Scopus, Web of Science, Cochrane, ScienceDirect, and ClinicalTrials.gov registry and adhered to the PRISMA guidelines.

Results

The results obtained confirm the high efficacy and safety of the SRS procedure in treating drug-resistant intention tremor. The study results present high response rate reaching 80% and achievement of manual task improvement, lessening of the tremor and increase in the quality of life of the majority of the operated patients. The method also stands out for its favorable balance between efficiency and cost.

Disscusion

Stereotactic radiosurgery is a favourable, safe, efficient and cost-effective method in treatment of the essential tremor. Ongoing research is crucial to refine patient selection criteria for this procedure and further improve the effectiveness of the technique.

Dosimetric Comparison of Dedicated Radiosurgery Platforms for the Treatment of Essential Tremor: Technical Report

Essential tremor (ET) is one of the most common adult movement disorders. As the worldwide population ages, the incidence and prevalence of ET is increasing. Although most cases can be managed conservatively, there is a subset of ET that is refractory to medical management. By virtue of being "reversible", deep brain stimulation (DBS) of the ventral intermediate nucleus (VIM) of the thalamus is one commonly accepted intervention. As an alternative to invasive and expensive DBS, there has been a renaissance in treating ET with lesion-based approaches, spearheaded most recently by high-intensity focused ultrasound (HIFU), the hallmark of which is that it is non-invasive. Meanwhile, stereotactic radiosurgical (SRS) lesioning of VIM represents another time-honored lesion-based non-invasive treatment of ET, which is especially well suited for those patients that cannot tolerate open neurosurgery and is now also getting a "second look". While multiple SRS platforms have been and continue to be used to treat ET, there is little in the way of dosimetric comparison between different technologies. In this brief technical report we compare the dosimetric profiles of three major radiosurgical platforms (Gamma Knife, CyberKnife Robotic Radiosurgery, and Zap-X Gyroscopic Radiosurgery (GRS)) for the treatment of ET. In general, the GRS and Gamma Knife were shown to have the best theoretical dosimetric profiles for VIM lesioning. Nevertheless the relevance of such superiority to clinical outcomes requires future patient studies.