A device that uses transcranial focused ultrasound to destroy the MRI-identified pathologic area of the thalamus in essential tremor patients became the first of its kind to receive Food and Drug Administration approval for use in patients whose condition has been refractory to medications such as beta-blockers or anticonvulsant drugs.
In patients who have undergone evaluation by CT and MRI to determine their suitability for the procedure, the Exablate Neuro device delivers focused ultrasound at incrementally higher energies until patients achieve a reduction of tremor. Patients are awake and responsive during the entire treatment.
“As with other treatments for essential tremor, this new device is not a cure but could help patients enjoy a better quality of life,” said Carlos Peña, PhD, director of the division of neurological and physical medicine devices in the FDA’s Center for Devices and Radiological Health, in the agency’s announcement of the approval. The device “could help them to avoid more extensive surgical treatments,” such as thalamotomy or a deep brain stimulation device, Dr. Peña said.
The clinical data used to support the approval included a double-blind, controlled trial of 76 patients with essential tremor who had not responded to medication therapy.
The 56 patients who were randomly selected to receive the Exablate Neuro treatment showed nearly a 50% improvement in their tremors and motor function 3 months after treatment, compared with their baseline score. The 20 patients who received a sham control treatment had no improvement, and some experienced a slight worsening after the sham procedure before they crossed over into the treatment group at the 3-month time point.
At 12 months post procedure, the treatment group retained a 40% improvement in those scores, compared with baseline.
Adverse events reported by patients treated with the device were similar to those reported by patients who have undergone thalamotomy. Events included numbness/tingling of the fingers, headache, imbalance/unsteadiness, loss of control of body movements (ataxia), or gait disturbance.
Other side effects identified as possibly related to treatment with MR-guided focused ultrasound treatments include tissue damage in an area other than the treatment area, hemorrhage in the treated area requiring emergency treatment, skin burns with ulceration of the skin, skin retraction, and scar formation and blood clots.