- Last Updated: May 9, 2018
Focused ultrasound treatment for Essential Tremor has been approved by the Food and Drug Administration (FDA) in July 2016.
Essential tremor (ET) is the most common movement disorder, affecting an estimated 3% of the population, or approximately 10 million individuals in the United States. ET is commonly viewed as a relatively benign disease.
However, the associated disabling aspects of ET, such as significant tremor of the hands, can impair patients’ ability to eat, shave, write, perform household activities, and function in the workplace.
The underlying etiology of ET is unclear, but cases often run in families (familial tremor). It has been estimated that approximately 50% of all cases are due to a genetic mutation, and the pattern of inheritance is most consistent with autosomal dominant transmission (i.e. dominant trait).
Focused Ultrasound Therapy
Focused ultrasound is a completely non-invasive method of thalamotomy - a procedure in which a predefined small volume of brain tissue containing nerve cells causing the tremor is destroyed - that could be an effective option for certain patients. It is performed while the patient is awake and involves no anesthesia, no incisions in the scalp, and no burr holes through the skull or insertion of electrodes into the brain. During focused ultrasound therapy, target cells in the thalamus are visualized in real time using MR imaging. The highly precise treatment uses focused beams of acoustic energy to heat and destroy target cells without harming adjacent tissue.
Most clinical studies with MR-guided Focused Ultrasound (MRgFUS) and essential tremor have targeted a region in the thalamus involving the Vim nucleus and were performed on only one side of the brain, for reasons noted under RF ablation above. Recent studies from Switzerland demonstrated safety and efficacy in targeting a different part of the thalamus called the cerebellothalamic tract (CTT), below the thalamus. Three out of 21 patients in this study received treatments on both the right and left sides with no significant adverse events and had significant improvement clinically, thus raising the possibility of treating patients bilaterally. To learn more about the CTT approach see the Center for Ultrasound Functional Neurosurgery Solothurn website.
Focused ultrasound may offer the following benefits in treating ET:
- It is a non-invasive, single treatment that enables patients to recover rapidly and quickly return to activities of normal life (usually the next day).
- Compared to RF ablation or DBS, focused ultrasound offers a reduced risk of infection, of damage to the non-targeted area, and of blood clot formation.
- Focused ultrasound offers rapid resolution of symptoms.
- In contrast to lesioning performed with stereotactic radiosurgery, focused ultrasound does not use ionizing radiation, thus avoiding the side effects of exposure to radiation.
- Because it is non-invasive, focused ultrasound could be an option for medically refractory ET patients (those who do not respond well to medication) who do not want to undergo surgery.
Phase 3 Pivotal Clinical Study
Enrollment has been completed in a multi-center pivotal randomized study to evaluate the safety and efficacy of focused ultrasound for the treatment of medication-refractory essential tremor patients. Results of this study have been reviewed and approved by the FDA.
Please see a list of possible treatment sites here.
Regulatory & Reimbursement
The ExAblate system manufactured by Insightec earned FDA approval to treat essential tremor in July 2016. It is also approved for treating essential tremor in Europe, Korea, Canada, Israel, Japan and Russia.
In the US, Medicare, at a national level, allows payment, at a level of nearly $17,000. However, the regional payment centers for Medicare still need to approve the procedure for payment in that region, and we are not aware of any regions that are paying for this care at the present time. These regions are different for various parts of the country, so patients should inquire from their physician regarding the local regional decisions. Many centers are putting patients on a waiting list until they get confirmation that local payment status has been approved.
Although the code for this care (0398T) has been approved to move to the payable class, it will not transition to the updated codes until 2019. Until then, it is more likely that payment rejections will have to be appealed in order to ensure payment.
Commercial coverage and Medicaid will typically follow Medicare but should be evaluated with each company and region. Some facilities have a cash payment option, for those who are not willing to wait for insurance decisions for payment. Prices vary, but a rough estimate is $40,000.
Insightec has established an informational website, including patient stories and access to treatment site information. They have also set up a Reimbursement Support Manager, who can help with questions about the status of reimbursements. Her contact information is: Kim Martin, Reimbursement Support Manager, 1-(866) 392-8478 or .
Krishna V, Sammartino F, Agrawal P, Changizi BK, Bourekas E, Knopp MV, Rezai A. Prospective Tractography-Based Targeting for Improved Safety of Focused Ultrasound Thalamotomy. Neurosurgery. 2018 Mar 21. doi: 10.1093/neuros/nyy020.
Jung NY, Park CK, Chang WS, Jung HH, Chang JW. Effects on cognition and quality of life with unilateral magnetic resonance-guided focused ultrasound thalamotomy for essential tremor. Neurosurg Focus. 2018 Feb;44(2):E8. doi: 10.3171/2017.11.FOCUS17625.
Chazen JL, Sarva H, Stieg PE, et al. Clinical improvement associated with targeted interruption of the cerebellothalamic tract following MR-guided focused ultrasound for essential tremor. J Neurosurg. October 2017:1-9. doi:10.3171/2017.4.JNS162803.
Kim M, Jung NY, Park CK, Chang WS, Jung HH, Chang JW. Comparative Evaluation of Magnetic Resonance-Guided Focused Ultrasound Surgery for Essential Tremor. Stereotact Funct Neurosurg. 2017 Aug 16;95(4):279-286. doi: 10.1159/000478866.
Niranjan A, Raju SS, Monaco EA 3rd, Flickinger JC, Lunsford LD. Is staged bilateral thalamic radiosurgery an option for otherwise surgically ineligible patients with medically refractory bilateral tremor? J Neurosurg. 2017 Apr 7:1-10. doi: 10.3171/2016.11.JNS162044.
Ravikumar VK, Parker JJ, Hornbeck TS, Santini VE, Pauly KB, Wintermark M, Ghanouni P, Stein SC, Halpern CH. Cost-effectiveness of focused ultrasound, radiosurgery, and DBS for essential tremor. Mov Disord. 2017 Apr 3. doi: 10.1002/mds.26997.
Schlesinger D, Lee M, Ter Haar G, Sela B, Eames M, Snell J, Kassell N, Sheehan J, Larner J, Aubry JF. Equivalence of cell survival data for radiation dose and thermal dose in ablative treatments: analysis applied to essential tremor thalamotomy by focused ultrasound and gamma knife. Int J Hyperthermia. 2017 Jan 3:1-27. doi: 10.1080/02656736.2016.1278281.
Hughes A, Huang Y, Pulkkinen A, Schwartz ML, Lozano AM, Hynynen K. A numerical study on the oblique focus in MR-guided transcranial focused ultrasound. Phys Med Biol. 2016 Nov 21;61(22):8025-8043.
Jang C, Park HJ, Chang WS, Pae C, Chang JW. Immediate and Longitudinal Alterations of Functional Networks after Thalamotomy in Essential Tremor. Front Neurol. 2016 Oct 24;7:184.
Elias WJ, Lipsman N, Ondo WG, Ghanouni P, Kim YG, Lee W, Schwartz M, Hynynen K, Lozano AM, Shah BB, Huss D, Dallapiazza RF, Gwinn R, Witt J, Ro S, Eisenberg HM, Fishman PS, Gandhi D, Halpern CH, Chuang R, Butts Pauly K, Tierney TS, Hayes MT, Cosgrove GR, Yamaguchi T, Abe K, Taira T, Chang JW. A Randomized Trial of Focused Ultrasound Thalamotomy for Essential Tremor. N Engl J Med. 2016 Aug 25;375(8):730-9. doi: 10.1056/NEJMoa1600159.
Bond AE, Dallapiazza R, Huss D, Warren AL, Sperling S, Gwinn R, Shah BB, Elias WJ. A Randomized, Sham-Controlled Trial of Transcranial Magnetic Resonance-GuidedFocused Ultrasound Thalamotomy Trial for the Treatment of Tremor-Dominant, Idiopathic Parkinson Disease. Neurosurgery. 2016 Aug;63 Suppl 1:154. doi: 10.1227/01.neu.0000489702.18785.5f.
Gallay MN, Moser D, Rossi F, Pourtehrani P, Magara AE, Kowalski M, Arnold A, Jeanmonod D. Incisionless transcranial MR-guided focused ultrasound in essential tremor: cerebellothalamic tractotomy. J Ther Ultrasound. 2016 Feb 13;4:5. doi: 10.1186/s40349-016-0049-8. eCollection 2016.
Click here for additional references from PubMed.
Pre- and post-treatment assessment videos courtesy of University of Virginia