Pallidal deep brain stimulation for primary dystonia in children

Background: Deep brain stimulation (DBS) at the internal globus pallidus (GPi) has replaced ablative procedures for the treatment of primary generalized dystonia (PGD) because it is adjustable, reversible, and yields robust clinical improvement that appears to be long lasting. Objective: To describe the long-term responses to pallidal DBS of a consecutive series of 22 pediatric patients with PGD. Methods: Retrospective chart review of 22 consecutive PGD patients, ≤21 years of age treated by one DBS team over an 8-year period. The Burke-Fahn-Marsden Dystonia Rating Scale (BFMDRS) was used to evaluate symptom severity and functional disability, pre- and post-operatively. Adverse events and medication changes were also noted. Results: The median follow-up was 2 years (range, 1-8 years). All 22 patients reached 1-year follow-up; 14 reached 2 years, and 11 reached 3 years. The BFMDRS motor subscores were improved 84%, 93%, and 94% (median) at these time points. These motor responses were matched by equivalent improvements in function, and the response to DBS resulted in significant reductions in oral and intrathecal medication requirements after 12 and 24 months of stimulation. There were no hemorrhages or neurological complications related to surgery and no adverse effects from stimulation. Significant hardware-related complications were noted, in particular, infection (14%), which delayed clinical improvement. Conclusion: Pallidal DBS is a safe and effective treatment for PGD in patients <21 years of age. The improvement appears durable. Improvement in device design should reduce hardware-related complications over time.