FOCUSED ULTRASOUND FOR THE TREATMENT OF ESSENTIAL TREMOR TARGETING THE VENTRALIS INTERMEDIUS NUCLEUS AND THE ZONA INCERTA

Research Spotlight: New Targets in Treating Essential Tremor  , A team in London has developed a new method for treating essential tremor patients involving ablating two areas in the brain.  READ MORE >

BEYOND THE THALAMUS - UNILATERAL MR GUIDED FOCUSED ULTRASOUND FOR
THE TREATMENT OF ESSENTIAL TREMOR TARGETING THE VENTRALIS
INTERMEDIUS NUCLEUS AND THE ZONA INCERTA
A.J. Jameel1
, P.G. Bain2
, D Nandi1
, B Jones1
, O Kirmi1
, W Gedroyc1
1
Imperial College NHS Healthcare Trust, London. 2
Imperial College of Science Technology and
Medicine, London. E-mail: Ayesha.jameel@nhs.net; wladyslaw.gedroyc@imperial.ac.uk
INTRODUCTION:
Magnetic Resonance guided focussed ultrasound (MRgFUS) is non-invasive
treatment for essential tremor (ET) that allows targeted thermal ablation of brain
tissue under real time image guidance. Previous studies have demonstrated
targeting the thalamic Ventral Intermedius Nucleus (Vim) to be an effective
treatment in ET; this paper describes the world’s first trial using MRgFUS to target
both the thalamic Vim and the subthalamic Zona Incerta (ZI).
METHODS:
A prospective study enrolled 13 patients with medication refractory ET for unilateral
MRgFUS procedure. Tremor severity was assessed using the Bain and Findley Spirals
(BFS). Spirals were collated immediately pre-procedure, after targeting the Vim and
after targeting the ZI. These spirals were anonymised, randomised and scored by
three blinded movement disorder Neurology Consultants. The percentage
improvement in the spiral scores after Vim ablation and after ZI ablation were
compared and analysed.
RESULTS:
In all patients there was successful thermal ablation of the target tissue at the Vim
and ZI. The mean percentage BFS improvement after Vim lesioning was 42.0% (11.1-
81.8%). The mean percentage BFS improvement after Vim and ZI lesioning was
66.7% (18.8- 81.8%). The mean additional benefit of targeting the ZI was 24.6%
(range 0% to 55.5%). There were no permanent significant adverse effects.
CONCLUSIONS:
Our study demonstrates the additional benefit of targeting the ZI alongside the Vim
in a unilateral MRgFUS procedure for the treatment of ET. No significant permanent
adverse events occurred after Vim and ZI ablation. Our study provides further
evidence that MRgFUS is a safe, effective, curative treatment for ET.