High-intensity focused ultrasound (HIFU) is an incision-free, minimally invasive outpatient procedure during which MRI-guided ultrasound is directed at the ventral intermediate (VIM) nucleus of the thalamus. HIFU precisely targets the area of the brain implicated in tremors without harming surrounding healthy tissue.
At the UCSF Movement Disorders Clinic, neurosurgeon Doris Wang, MD, PhD, has successfully used HIFU to stop tremors in several patients with movement disorders who either aren’t good candidates for deep brain stimulation (DBS) or wish to avoid brain implants.
Tremor control better with HIFU than DBS in patient with ET
A 76-year-old right-handed man with long-standing essential tremor (ET) previously underwent DBS of the VIM nucleus of the thalamus, which was complicated by multiple hardware-related infections. The hardware was reimplanted but eventually removed after it eroded through the scalp. The patient has a medical history of multiple comorbidities, including non-insulin-dependent diabetes mellitus (NIDDM) and coronary artery disease status post two-vessel coronary artery bypass graft surgery (CABG) 16 years earlier.
He came to UCSF with right-hand-dominant intention tremor, which rated 58 on the Fahn-Tolosa-Marin tremor rating scale (19 on part A, 21 on part B and 18 on part C). Due to the patient’s prior DBS hardware-related infections and known NIDDM, Wang determined that left-sided focused ultrasound (FUS) thalamotomy was the most appropriate treatment.
Following the procedure, the patient’s tremor control improved by about 95 to 100%. He was able to write legibly and walk across the room carrying a beverage in one hand without difficulty. He reports that his tremor control is better than he achieved with DBS.
“He can carry out daily tasks without tremor and is very happy with the outcome,” Wang said.
Relief for patient with tremor-dominant Parkinson’s disease
A 75-year-old left-handed man with tremor-dominant Parkinson’s disease (PD) was referred to UCSF by Veterans Affairs. He had been taking Sinemet (carbidopa and levodopa) five times a day, but his left-hand tremor did not subside, so he discontinued the medication.
Because the patient lives in a remote area, the multiple clinic visits required to adjust DBS settings would have been burdensome for him. “He doesn't have easy access to care and has minimal other Parkinson’s symptoms such as a rigidity and bradykinesia,” Wang said. “HIFU was a good choice for him.”
After Wang treated the patient with HIFU, his left-hand action and postural tremors stopped. He still experiences a resting tremor but can control it by focusing on it or moving his arm. The patient reports that he is “thrilled and amazed” by the results.
Neurology and neurosurgery research and treatment take place within the UCSF Weill Institute for Neurosciences.
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