A non-incision surgical procedure using focused intraglobus pallidus ablation (FUSA) in patients with Parkinson’s disease (PD) significantly reduces tremor and improves mobility in patients with progressive disease. A new study shows an improvement.
The technique does not require sedation or brain implants. The surgeon uses his MRI to identify the inner globus pallidus, the part of the basal ganglia involved in the movement disorder, and uses focused ultrasound beams to heat and destroy the tissue.
Investigators used a device called the Exablate Neuro to perform the procedure. first approved It was approved by the US Food and Drug Administration in 2016 to treat essential tremor.
Based on the results of a multicenter, randomized, sham-controlled trial, the agency expanded Indications for 2021 include unilateral pallidectomy to treat advanced PD in patients with symptoms of mobility, stiffness, or dyskinesias.
Dr. Baiber Krishna
“Some people with Parkinson’s disease develop dyskinesias, and ablation of the globus pallidum can prevent these dyskinesias and movement disorders,” said Baivar Krishna, M.D., associate professor of neurosurgery and principal investigator at the University of North Carolina at Chapel Hill. will be greatly reduced,” he said. Medscape Medical News“It may be used to treat patients in whom other surgical procedures are not amenable.”
research is publish online February 23rd New England Journal of Medicine.
strong reaction
In this study, 94 patients with progressive PD who had dyskinesias or motor fluctuations and impaired movement in the unmedicated state wore transducer helmets while lying in an MRI scanner. The patient remained awake throughout the operation.
The treatment group received unilateral FUSA on the side of the brain with the greatest motor impairment. The device initially offered a target temperature of 40-45 degrees Celsius. To test improvement in motor symptoms, the ablation temperature was gradually increased following assessment. The maximum temperature used was 54.3 degrees Celsius.
Patients in the control group received the same treatment with the ultrasound energy disabled.
The primary outcome was response to treatment at 3 months, with a Movement Disorders Society-Unified Parkinson’s Disease Rating Scale (MDS-UPDRS), Part III score of at least 3 points from baseline while off medication defined as having decreased. or score on the Integrated Dyskinesia Rating Scale (UDRS) while on medication.
At 3 months, 69% of the treatment group reported a response compared to 32% of the control group (P. = .003).
When the researchers analyzed MDS-UPDRS scores, improvement was seen in 29% of the treatment group and 27% of the control group. UDRS scores improved in 12% of treatment groups. There was no improvement in this score in the control group. Improvements in both scores were reported in 28% of the treatment group and 5% of the control group.
Of those who reported a response at 3 months, 77% continued to have a response at 12 months.
The “unforgiving” region of the brain
Although the response rate was a promising sign of this discovery, it was not what Krishna was most interested in.
“The most surprising finding of this trial is how safe focused ultrasound pallidectomy is in treating patients with Parkinson’s disease,” he said.
The globus pallidus is the region of the brain that Krishna calls “merciless”.
“On one side are the motor nerve fibers, and a problem with this can paralyze the patient. Just below that is the optic nerve tract, and a problem there can lead to blindness,” said Krishna. . “It’s a very tough area.”
By using MRI-guided ultrasound, surgeons can change the target and temperature of the ultrasound beam during the procedure, allowing for more precise treatment.
Pallicotomy-related adverse events in the treatment group included dysarthria, gait disturbance, taste disturbance, visual disturbance, and facial weakness. According to Krishna, all were mild to moderate.
more research needed
Dyskinesias are a challenge in the management of PD. Patients require antiparkinsonian drugs to slow the decline in motor function, but these drugs can cause the involuntary movements characteristic of dyskinesias.
Deep brain stimulation (DBS), the most common treatment for this complication, has its own drawbacks. This is an open surgery with a low level of risk of intracranial bleeding and infection. Additionally, electrode implants require ongoing maintenance and adjustments.
However, the results of this study indicate that FUSA may be an alternative therapy for patients who are not candidates for other treatments such as DBS or ablative radiofrequency, said the clinical neurosurgeon at University College London. Dr. Anette Schrag, Professor of Science, writes: Accompanying commentary.
“The results confirm that it is effective, at least in the short term, in reducing the motor complications of Parkinson’s disease,” writes Schrag.
But longer-term studies are needed, she adds.
One-third of patients in the treatment arm did not respond to treatment, and researchers are not sure why. Dr. Krishna noted that within a year of starting treatment, about a quarter of his patients had become less effective with the treatment.
The researchers plan to explore these issues in future trials.
“The results of this trial are encouraging,” writes Schrag. All patient functions and quality of life improved. ”
This study was funded by Insightec.Disclosure Form Krishna and Shlag website.
N Engl J Med. Published online on February 23, 2023. overview
Kelli Whitlock Burton is a Medscape Medical News reporter covering neurology and psychiatry.
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