Adoption of focused ultrasound thalamotomy for essential tremor: why so much fuss about FUS?

Abstract

BackgroundFocused ultrasound (FUS) was approved as a new treatment modality for essential tremor (ET) in 2016. The goal of this study was to quantify FUS adoption for ET and understand its drivers.MethodsThe adoption of the various surgical options for ET was estimated using three measures: the number of presentations on the various surgical treatments for ET at specialised international meetings, the number of original papers published as identified by literature searches and the number of thalamotomy procedures performed worldwide for ET as provided by device manufacturers’ registries.ResultsFirst, we found that the number of presentations related to lesioning procedures is increasing relative to deep brain stimulation (DBS) at international meetings. Second, there are already more publications on FUS (93) than stereotactic radiosurgery (SRS) (68) or radiofrequency (43) for ET, although they still lag behind DBS papers (750). Third, the number of annual FUS thalamotomies performed for ET (n>1200 in 2019) in 44 centres has surpassed the annual procedures across 342 Gamma Knife units (n<400, 2018) but is yet to reach the number of DBS cases for ET estimated at over 2400/year.ConclusionFUS is being rapidly adopted for the treatment of ET. We hypothesise that its perceived minimally invasive nature coupled with the ability to perform intraoperative clinical assessments, its immediate effects and active marketing efforts are contributing factors. As lesioning modalities for the treatment of ET are reappraised, the superior popularity of FUS over SRS appears to arise for reasons other than differences in clinical outcomes.

Diagnosis and Treatment of Essential Tremor

“…The MRgFUS procedure does not require drilling of a burr hole and implantation of hardware. It is essential to discuss that complete hair removal is needed, and the patients will need to lie in an MRI scanner for 3 to 4 hours during the MRgFUS procedure 74 . No data are available on long-term follow-up or whether unilateral MRgFUS can effectively control axial symptoms such as head tremor.…”

Rationale and Evidence for Peripheral Nerve Stimulation for Treating Essential Tremor

“…The FDA-approved treatments such as deep brain stimulation (DBS) surgery [ 9 ] and focused ultrasound therapy are considered when the tremor shows refractoriness to oral medications [ 10 11 ]. These treatments are powerful as they directly target the pathogenic brain circuitry [ 12 13 ]. However, given the risks and limitations, surgical therapies are not recommended as first-line treatments [ 14 ].…”

Bilateral Focused Ultrasound Thalamotomy for Essential Tremor (BEST‐FUS Phase 2 Trial)

“…In contrast to other surgical approaches, such as deep brain stimulation (DBS) and radiofrequency thalamotomy, no skin incisions or brain penetration is required, and the procedure is often administered in an ambulatory care setting. These attributes contribute in large part to its appeal among patients 6 . On the basis of the efficacy and safety of this approach, unilateral MRgFUS has been approved as a therapy by regulatory agencies including the U.S. Food and Drug Administration and the European Commission 7…”

“…These attributes contribute in large part to its appeal among patients. 6 On the basis of the efficacy and safety of this approach, unilateral MRgFUS has been approved as a therapy by regulatory agencies including the U.S. Food and Drug Administration and the European Commission. 7 Notwithstanding this therapeutic advance, ET is a generalized disorder with bilateral symptoms, particularly affecting both arms.…”