Subthalamic Nucleus Stimulation in Pediatric Isolated Dystonia: A 10-Year Follow-up

Objective: To evaluate the short-term and long-term clinical effectiveness and safety of subthalamic nucleus deep brain stimulation (STN-DBS) for medically intractable pediatric isolated dystonia. Methods: Using a longitudinal retrospective design, we assessed the clinical outcomes of nine patients who underwent STN-DBS for treatment-refractory pediatric isolated dystonia one decade ago (mean age at surgery: 15.9 +/- 4.5 years). The primary clinical outcome used was assessed by retrospective video analyses of patients' dystonia symptoms using the Burke-Fahn-Marsden Dystonia Rating Scale (BFMDRS). Clinical assessments were performed at baseline, 1-year follow-up (1-yr FU), and 10-year follow-up (10-yr FU). Adverse side effects, including surgery-related, device-related, and stimulation-related effects, were also documented. Results: After STN-DBS surgery, the mean improvement in the BFMDRS motor score was 77.1 +/- 26.6% at 1-yr FU and 90.4 +/- 10.4% at 10-yr FU. Similarly, the mean BFMDRS disability score was improved by 69.5 +/- 13.6% at 1-yr FU and by 86.5 +/- 13.9% at 10-yr FU. The clinical improvements gained at 10-yr FU were significantly larger than those observed at 1-yr FU. Negative correlations were found between the duration of disease to age at surgery ratio (DD/AS) and the improvements in the BFMDRS motor score and total score at 1-yr FU and 10-yr FU. Conclusion: To our knowledge, this study provides the first clinical evidence for the short- and long-term effectiveness and safety of STN-DBS for pediatric isolated dystonia. Additionally, putative evidence is provided that earlier STN-DBS intervention in patients with refractory pediatric isolated dystonia may improve short- and long-term clinical outcomes.