When you were around 6 or 7 years old, you might have been one of those kids who lost both front teeth around the same time, leaving you with a big gap in your smile. And, if you were that age in 1961 and the winter holidays were just around the corner, you might remember Alvin and the Chipmunks singing “All I Want for Christmas is My Two Front Teeth.” This song was a chart-topper for many kids in the same boat.
For persons with essential tremor (ET) of the hands that is not responsive to medication—or experience troubling side effects because of it—the idea of gaining normal hand function may seem like an unattainable dream. In fact, even when told that a neurosurgery called Deep Brain Stimulation (DBS) can help them, many reject the prospect of a long surgery during which holes in the skull are drilled through incisions in the scalp, electrode wires are placed in their brain, and a hardware power source is implanted in the chest with wires threaded via their neck to connect to the electrodes. While DBS has proven effective for 160,000 patients with ET, Parkinson’s disease or other neurological conditions, an unknown number of qualified ET patients simply can’t or won’t opt for it.
Focused Ultrasound revolutionizes ET treatment
On July 11, 2016, the U.S. Food and Drug Administration gave a very big present to the world of ET treatment. The agency announced its approval of the Exablate Neuro device produced by Insightec for the treatment of ET that does not respond to medication. Based on the success of two clinical trials phases, the FDA moved very quickly to make this outpatient, incisionless procedure available for those with hand tremors.
For the first time, there was a noninvasive alternative to DBS that was safe and effective, with very low rates of mild, temporary side effects. Now was a long-awaited solution for uncontrollable hand tremors, a solution that does not involve surgery, radiation or medication.
However, clinical studies in the U.S. and other countries had demonstrated that the safest way to do the procedure was to treat only the side of the brain that controlled the dominant hand. The reason for this has to do with the tiny size of the treated structure, the VIM nucleus of the thalamus. Just as the brain has a right and left hemisphere, the thalamus is also a paired structure in the center of the brain. Despite its small size, many pathways—including the tremor pathway—pass through its numerous nuclei, or “sub-centers.” The VIM nucleus is the tiny target area to interrupt the tremor pathway. By “zapping” it with focused beams of ultrasound energy, it is switched off, thus interrupting tremor messages. But because of its size and location, treating both sides may increase the risk for side effects such as gait disturbances, tingling sensations in the face, or speech problems.
Therefore, unlike bilateral DBS which can be done on both sides during a single neurosurgery, the American Society for Stereotactic and Functional Neurosurgery issued an April, 2019 Position Statement on FUS for ET that says, “…MRgFUS is not presently indicated for bilateral treatment…” either as a single procedure or as a two-stage procedure separated by many months.[i]
This is obviously disappointing for many persons who might want to sing a parody of the Chipmunks’ 1961 song: “All I want for Christmas is my two tremor-free hands.” But promising news is at hand.
European study investigates bilateral FUS treatment for ET
A new clinical trial launched in England and Spain is testing a staged approach to bilateral treatment of the VIM nucleus. The study will involve 30 patients whose dominant side will be treated; then, at least 9 months later, the opposite side will be treated. It may be hard to patiently wait for results through the lengthy process of qualifying participants, doing a first treatment, re-treating at least 9 months later, and following patients for a predetermined period of time to track the effectiveness and any adverse events. The anticipated reward will be worth it, as hinted by a March, 2019 press release from the Focused Ultrasound Foundation. After the first patient had completed both stages of the study, his doctor was quoted as stating, “At 74-years-old, he said after his bilateral procedure that he felt a whole man now for the first time in 60 years.”[ii] No doubt his 2019 winter holiday was very festive, indeed!
Sperling Neurosurgery Associates shares the gratitude of ET patients here and in other locations who have gained greater quality of life through the FUS Neuravive procedure. Even if only one hand was treated, their experience is a joyful one. We join them and countless others in waiting for the results of the bilateral trial, in hopes that its results will earn FDA approval. This will grant what we all wish for at Christmas or at any time of the year: two tremor-free hands.
NOTE: This content is solely for purposes of information and does not substitute for diagnostic or medical advice. Talk to your doctor if you are experiencing pelvic pain, or have any other health concerns or questions of a personal medical nature.
[ii] Focused Ultrasound Foundation. “First Patient Enrolled in Trial for Bilateral Treatment of Essential Tremor.” March 14, 2019. https://www.fusfoundation.org/news/first-patient-enrolled-in-trial-for-bilateral-treatment-of-essential-tremor