The US FDA has approved the first focused ultrasound device intended to treat essential tremor in patients who have not responded to previous treatment.
Essential tremor is typically treated with beta blockers or anticonvulsants, however patients who fail to respond to medication may undergo thalamotomy or deep brain stimulation. Treatment with ExAblate Neuro, manufactured by InSightec, is meant to be less invasive.
The new treatment uses MRI to guide focused ultrasound to the brain tissue that is thought to be causing the tremors.
“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, PhD, MS, director of the division of neurological and physical medicine devices in 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.”
Efficacy data submitted to the FDA included data from a double-blind control trial including 76 patients with refractory essential tremor. Fifty-six patients were randomized to the treatment group while 20 received sham treatment. Patients treated with the device showed nearly a 50% improvement in tremors and motor function 3 months after treatment compared to baseline. Twelve months post-treatment, the treatment group retained a 40% improvement in symptoms compared to baseline. Adverse events include numbness/tingling of the fingers, headache, imbalance, ataxia, or gait disturbance. Other adverse events that may be associated with the device treatment are hemorrhage in the treated area, skin burns and ulceration, skin retraction and scar formation, blood clots, and tissue damage in an area other than the targeted treatment area.
Patient eligibility should first be determined through MR and CT scans. Treatment is administered through incremental increases in ultrasound until a reduction in tremor is achieved. Patients who cannot have MRI, who have a non-MRI compatible implanted metallic device, those with allergies to MRI contrast agents, or those with body size limitations are not suitable for treatment with ExAblate Neuro. The treatment should also not be administered to patients who are pregnant, have kidney disease or are on dialysis, those with heart conditions, severe hypertension, those with drug abuse problems, abnormal bleeding or hemorrhage or blood clotting disorders. Those patients taking anticoagulants, those with a history or cerebrovascular disease or brain tumors, and those who can not tolerate staying in a stationary position for a period of time should not have the procedure.
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