Essential Tremor – Deep Brain Stimulation vs. Focused Ultrasound

ABSTRACT

Introduction

Essential Tremor (ET) is one of the most common tremor syndromes typically presented as action tremor, affecting mainly the upper limbs. In at least 30–50% of patients, tremor interferes with quality of life, does not respond to first-line therapies and/or intolerable adverse effects may occur. Therefore, surgery may be considered.

Areas Covered

In this review, the authors discuss and compare unilateral ventral intermedius nucleus deep brain stimulation (VIM DBS) and bilateral DBS with Magnetic Resonance-guided Focused Ultrasound (MRgFUS) thalamotomy, which comprises focused acoustic energy generating ablation under real-time MRI guidance. Discussion includes their impact on tremor reduction and their potential complications. Finally, the authors provide their expert opinion.

Expert opinion

DBS is adjustable, potentially reversible and allows bilateral treatments; however, it is invasive requires hardware implantation, and has higher surgical risks. Instead, MRgFUS is less invasive, less expensive, and requires no hardware maintenance. Beyond these technical differences, the decision should also involve the patient, family, and caregivers.

KEYWORDS:

• Essential tremor
• deep brain stimulation
• focused ultrasound
• tremor
• advanced management

Article highlights

• Essential Tremor is currently known as a heterogeneous syndrome with several underlying etiologies and at least 30–50% of patients do not respond or tolerate the first-line medications, requiring surgical interventions.

• DBS advantages includes adjustable and reversible nature, higher evidence of safety and efficacy of bilateral procedures and possibility of incorporation of emerging technologies.

• DBS is invasive, requires general anesthesia for pulse generator’s implantation, maintenance, a stricter selection process and has higher risk of procedure complications.

• MRgFUS allows brain lesions without skin, skull, or brain penetration, has no risk of bleeding or infections, and is less expensive. Also, staged bilateral MRgFUS thalamotomy has been recently approved by the FDA.

• MRgFUS cannot be adjusted in tremor worsening, tremor recurrence or side effects, and is contraindicated in cases of skull specifics (i.e. low SDR) and intolerance to MRI.

• The final selection of treatment modality should be driven by the medical team along with the patient and caregiver preferences.

Declaration of interest

A Fasano and AM Lozano have received honoraria and research support from Abbott, Boston Scientific and Medtronic, while AM Loazano has also received research support and honoraria from Insightech. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

Reviewer disclosures

Peer reviewers on this manuscript have no relevant financial or other relationships to disclose

Additional information

Funding

This work was partly funded by the University of Toronto/University Health Network Chair in Neuromodulation to A Fasano.