FDA approves MRI-guided focused ultrasound device to treat tremor

The FDA published the approval of the first focused ultrasound device for the treatment of essential tremor in people who did not respond to treatment. Magnetic resonance (MR) images are taken by ExAblate Neuro during application of focused ultrasound to kill the brain cells which are considered to cause this tremor.

“Patients with essential tremor who have not seen improvement with medication now have a new treatment option that could help them to avoid more invasive surgical treatments,” said Carlos Peña, who is the director of the division of neurological and physical medicine devices at the FDA’s Center for Devices and Radiological Health. “As with other treatments for essential tremor, this new device is not a cure but could help patients enjoy a better quality of life.”

Essential tremor, known as benign essential tremor, is a very frequent kind of tremor. The National Institute of Neurological Disorders and Stroke reports that millions middle aged (over the age of 40) Americans experience this malfunction. Current therapy for essential tremor includes anticonvulsant or beta blockers. If drugs fail to manage the condition, the patients can also undergo surgery (thalamotomy) or implantation of a deep brain stimulation device to destroy that little, involuntary movement controlling brain area.

ExAblate Neuro therapy is evaluated with the involvement of patients, who first receive MR and computerized tomography (CT) scans. Patients receiving treatment with the MRI-guided device lie in an MRI scanner that takes pictures to help a medical doctor recognize the relevant brain’s thalamic area for therapy. Therapy with transcranial focused ultrasound energy doses is given incrementally until patients experience a reduction of tremor. Patients are kept awake during the whole treatment.

The double-blind control clinical trial including 76 people supports the safety and effectiveness of this therapy. Participants with essential tremor did not respond to drug treatment. Fifty-six of the participants were randomly chosen to get the ExAblate Neuro therapy. Twenty received a placebo treatment. Control group was able to cross over into the treatment group three months later.

People who received the ExAblate Neuro treatment improved about 50% in their motor function and  tremors three months of therapy. Participants of the control group did not improve, and some of them became worse after the sham process before they were crossed over into the treatment group. After 12 months, the treatment group still kept a 40% improvement.

Adverse events for this therapy are similar to those for thalamotomy, such as finger tingling, numbness, imbalance/unsteadiness, headache, losing control of movements or gait dysfunctions. Other side effects are likely associated with MR-guided focused ultrasound treatments like tissue damage outside the treatment area, hemorrhage needing emergency treatment, skin burns with ulcer, scars, skin retraction, and blood clots.

The ExAblate Neuro treatment is contraindicated for people who cannot receive MR imaging, those also who have a non-MRI compatible metallic device implanted, like a cardiac pacemaker, those people who are suffering from allergies to MR contrast agents or those people who have body size limitations for MR. The therapy cannot be applied for pregnant women, people who have serious kidney disease or need dialysis, those whose heart conditions are unstable, who have serious hypertension, behavior consistent with ethanol/substance abuse, or who experience malfunctional bleeding, blood clotting dysfunction, hemorrhage. Patients with cerebrovascular disease or brain tumors are contraindicated to have this therapy.