In its first year of operation, Duke’s high-intensity focused ultrasound (HIFU) treatment for tremors has attracted more than 90 patients drawn to this noninvasive brain treatment option. 

HIFU is FDA-approved to treat essential tremor and tremor-dominant Parkinson’s disease. 

“Essential tremor is the most common movement disorder in America,” according to neurosurgeon Stephen Harward II, MD, PhD, co-director of Duke’s HIFU program. “It affects about 1% of the overall population and 4 to 5% of those over 65. Tremor-dominant Parkinson’s is less common but just as disabling as essential tremor.”

Traditionally, tremors that have proven refractory to medical therapies have been treated by inserting electrodes into the brain to perform deep brain stimulation or to make a lesion using radiofrequency ablation. As an incisionless surgical approach, HIFU offers numerous advantages over previous approaches. 

In HIFU, more than 1000 ultrasound beams are directed at a single point in the brain. A single ultrasound beam has no impact on the brain, but focusing 1000 beams together creates a lesion leading to instantaneous tremor benefit that appears to last for at least 5 years. The instant effect allows a patient’s tremors to be tested during the procedure to evaluate the response.

In preparation for the ultrasound treatment, the patient undergoes diffusion tensor imaging followed by tractography, an analysis that Harward likens to making a “road map” of the patient’s brain anatomy. “I can use that road map to make a personalized, targeted plan for that patient,” Harward says. “The goal is to ablate a small area within the thalamus approximately the size of a pea, about 5 or 6 millimeters in diameter.”

“HIFU is not a first-line therapy because there are good medical therapies that can provide benefits for many years,” Harward says. “However, in our most severe patients who have tried everything but are still not getting a satisfactory benefit, this lesional therapy can be an excellent next step in trying to obtain tremor control.”

HIFU is not a cure for tremor because it does not address the underlying pathology driving either essential tremor or tremor-dominant Parkinson’s disease. However, it has proven to excel at reducing symptoms with an average tremor improvement of 70%. Harward says that “it turns back the clock” on symptoms that will become progressively worse if not checked. HIFU can be easily repeated in patients whose results are suboptimal or whose symptoms return. 
 

Patients have been coming to Duke from across the Southeast and beyond to learn more about this therapy. Consultation appointments are available at clinics in both Raleigh and Durham with the procedure performed at Duke University Hospital in Durham.

Harward encourages referrals of patients whose issues with tremors continue despite the use of medication. “It is never too early to send them to us to start the conversation about more advanced therapies such as HIFU,” Harward says. “Even if it is not the right fit, it never hurts because patients always seem to benefit from more knowledge.”