Deep brain stimulation of the subthalamic nucleus was shown to remain effective in treating motor complications of people with Parkinson disease 15 years after initial surgery.
Deep brain stimulation (DBS) of the subthalamic nucleus (STN-DBS) may prove effective after more than 15 years in patients with Parkinson disease (PD), according to study findings published last week in Neurology.
Associated with several positive outcomes in patients with PD, including decreasing risk of disease progression, researchers say that STN-DBS has been shown to maintain efficacy in patients up to 11 years after surgery. However, conflicting reports have indicated DBS may lose efficacy over time.
“Initial post-operative quality of life (QOL) improvement has been described to fall to preoperative levels after 5-year stimulation, likely due to the escalation of both levodopa- and stimulation-resistant motor and nonmotor features of PD, such as impairments of gait, balance, speech and cognition,” said the study authors.
With a growing rate of PD diagnoses and number of STN-DBS procedures conducted, researchers note that large data examining efficacy after the second and third decades post-procedure is lacking, with small populations having been the focus of previous studies examining motor response from STN-DBS after more than 10 years.
Seeking to evaluate the long-term efficacy of STN-DBS beyond 15 years after surgery, researchers conducted a retrospective cohort study of patients with PD operated on with bilateral STN-DBS at the Grenoble Alpes University Hospital from 1993 to 2004 who met inclusion criteria (n = 51).
Participant data on motor complications, QOL, activities of daily living, Unified Parkinson’s Disease Rating Scale (UPDRS) motor scores, dopaminergic treatment, stimulation parameters, and side effects of STN-DBS, were examined and compared between before surgery, and at 1-year and beyond 15 years of follow-up after surgery.
Researchers assessed for the primary outcomes of change in the UPDRS-IV items (complications of therapy) at long-term follow-up (beyond 15 years) after STN-DBS compared to baseline, with changes in the time spent with dyskinesia and in the OFF state also evaluated.
A mean (SD) follow-up time of 17.06 ± 2.18 years was reported among the study cohort.
In their findings, patients who underwent STN-DBS exhibited a 75% decrease in the time spent with dyskinesia (P < .001) and a 58.7% reduction in the time spent in the OFF state (P < .001) after long term follow-up compared with baseline.
"Our study also found that despite the natural progression of PD and the worsening of some symptoms that become resistant to medications over the years, participants still maintained an overall improvement in QOL," study author Elena Moro, MD, PhD, of the Grenoble Alpes University in France and a Fellow of the American Academy of Neurology, said in a statement.
Improvements observed in long-term follow-up compared with baseline indicated a 13.8% improvement in QOL (P = .005), as measured by the Parkinson's Disease Quality of Life Questionnaire (PDQL), a 13.6% improvement in emotional function (P = .01), and a 29.9% improvement in social function (P < .001).
Use of dopaminergic drugs were also found to be reduced by 50.6% (P < .001) after long-term follow-up, with few and mostly manageable device-related adverse events observed during the follow-up, noted study authors.
"Future studies should continue to examine the benefits of deep brain stimulation over longer periods of time and in larger groups of people," said Moro.
Bove F, Mulas D, Cavallieri F, et al. Long-term outcomes (15 Years) after subthalamic nucleus deep brain stimulation in patients with Parkinson disease. Neurol. Published online June 2, 2021. doi:10.1212/WNL.0000000000012246