High intensity ultrasound was first utilized as a treatment for the brain in the 1940’s and 1950’s. Its rebirth should not be a surprise, as combining this technology with high field MRI scanning has the potential to lead to a powerful therapeutic tool. Ultrasound therapy for tremor, and potentially also for Parkinson’s disease has great appeal to patients, as it does not require a scalp incision or a craniotomy. The therapy also has distinct advantages over gamma knife and other radiosurgery techniques. In radiosurgery, unlike in ultrasound, you do not have the ability to apply a test-lesion prior to placing a permanent lesion. Additionally, radiosurgery carries the potential for radiation necrosis, runaway brain lesions, and delayed complications.
-Similar risks to conventional thalamotomy
-Formation of a brain lesion is part of ultrasound and conventional thalamotomy
-Bilateral approach or two sided brain surgery is discouraged for ultrasound therapy because of side effects (cognition, pseudobulbar)
-4/15 subjects (26.7%) had persistent sensory issues; when these occur with deep brain stimulation (DBS) re-programming of the device leads to symptom resolution
-Microelectrode recording and physiological mapping are not done in ultrasound
-Precision of the lesion is a big hurdle for the therapy as it moves toward trials in Parkinson's disease
-There are no wires or pacemakers with ultrasound therapy
The abstract of the actual study published in the NEJM on ultrasound therapy and tremor is provided below but we would refer you to the journal for the article by Elias and colleagues.
A Pilot Study of Focused Ultrasound Thalamotomy for Essential Tremor
W. Jeffrey Elias, M.D., Diane Huss, P.T., D.P.T., N.C.S., Tiffini Voss, M.D., Johanna Loomba, B.S., Mohamad Khaled, M.D., Eyal Zadicario, M.Sc., Robert C. Frysinger, Ph.D., Scott A. Sperling, Psy.D., Scott Wylie, Ph.D., Stephen J. Monteith, M.D., Jason Druzgal, M.D., Ph.D., Binit B. Shah, M.D., Madaline Harrison, M.D., and Max Wintermark, M.D.
Recent advances have enabled delivery of high-intensity focused ultrasound through the intact human cranium with magnetic resonance imaging (MRI) guidance. This preliminary study investigates the use of transcranial MRI-guided focused ultra- sound thalamotomy for the treatment of essential
From February 2011 through December 2011, in an open-label, uncontrolled study, we used transcranial MRI-guided focused ultrasound to target the unilateral ventral intermediate nucleus of the thalamus in 15 patients with severe, medication-refrac- tory essential tremor. We recorded all safety data and measured the effectiveness of tremor suppression using the Clinical Rating Scale for Tremor to calculate the total score (ranging from 0 to 160), hand subscore (primary outcome, ranging from 0 to 32), and disability subscore (ranging from 0 to 32), with higher scores indicating worse tremor. We assessed the patients’ perceptions of treatment efficacy with the Quality of Life in Essential Tremor Questionnaire (ranging from 0 to 100%, with higher scores indicating greater perceived disability).
Thermal ablation of the thalamic target occurred in all patients. Adverse effects of the procedure included transient sensory, cerebellar, motor, and speech abnor- malities, with persistent paresthesias in four patients. Scores for hand tremor im- proved from 20.4 at baseline to 5.2 at 12 months (P=0.001). Total tremor scores improved from 54.9 to 24.3 (P=0.001). Disability scores improved from 18.2 to 2.8 (P=0.001). Quality-of-life scores improved from 37% to 11% (P=0.001).
In this pilot study, essential tremor improved in 15 patients treated with MRI- guided focused ultrasound thalamotomy. Large, randomized, controlled trials will be required to assess the procedure’s efficacy and safety. (Funded by the Focused Ultrasound Surgery Foundation; ClinicalTrials.gov number, NCT01304758.)
n engl j med 369;7 nejm.org august 15, 2013