Treating tremor in Parkinson’s patients using non-invasive and focused-ultrasound lesion surgery is associated with better quality of life when compared to deep brain stimulation, although both approaches are equally effective in easing this disease symptom, a review study reports.
The study, “Outcomes in Lesion Surgery versus Deep Brain Stimulation in Patients with Tremor: A Systematic Review and Meta-analysis,” was published in the journal World Neurosurgery.
At least 50 percent of people with Parkinson’s, essential tremor (ET) or multiple sclerosis (MS) given oral medications as a first-line treatment for tremor — defined as an involuntary, uncontrollable muscle contraction; most commonly in the hands — do not tolerate these medications over the long term.
Current alternatives include deep brain stimulation (DBS) and lesion surgery (LS), which induces lesions on targeted areas using a heated electrode or focused ultrasound. Prior comparisons have shown that while the two techniques are equally effective in suppressing tremor, DBS led to a greater improvement in function.
But LS with focused ultrasound is gaining in popularity, and one study suggested that it may significantly improve tremor and quality of life.
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Researchers at Harvard Medical School conduced a systematic review and a meta-analysis — a type of statistical study that combines the results of various studies — to determine which strategy is most effective in diminishing tremor severity and improving life quality and function in people with Parkinson’s, ET, or MS.
Three online databases were searched for results of randomized clinical trials published up to Jan. 1, 2018, and that included adults treated with either LS or DBS, or serving as controls. Both DBS and LS studies targeted unilateral or bilateral thalamus, pallidum or subthalamic nucleus, all of which are implicated in motor function.
Thirteen Parkinson’s trials were among the 15 included in this study, and the primary outcome for all but one was change in upper limb tremor severity, as assessed with the unified Parkinson’s disease rating scale (UPDRS) part III. Changes in quality of life, cognitive function and neuropsychiatric function were also assessed with variable measures.
A total of 1, 508 patients (mean age range, 48.4 to 70.8) were included, and in addition to the 13 studies involving only Parkinson’s patients, one study looked at people with Parkinson’s, ET and MS, while the remaining study was in people with severe ET.
Four of the 15 trials — involving 125 patients — directly compared DBS to LS. The others compared either LS or DBS with controls.
Results showed that DBS and LS were not significantly different across all analyzed outcomes, which is in line with current guidelines, the researchers noted. All but one trial showed both these types of surgery eased tremor severity. Quality of life findings showed variability in outcomes, which was driven by disease duration. Specifically, longer disease duration correlated with a greater likelihood of surgery and better quality of life.
A subgroup analysis that looked specifically at LS using focused ultrasound revealed that this approach was associated with a significant improvement in quality of life compared to DNS, although changes in tremor severity were similar.
“Policy makers, healthcare providers, and patients could therefore consider focused-ultrasound [LS] as a potential choice for tremor control, based on currently available evidence,” the researchers wrote.
However, results from more studies directly comparing DBS with focused-ultrasound LS are needed, they advised.