Deep Brain Stimulation in DYT1 Dystonia: A 10-year Experience.

BACKGROUND: Globus Pallidus Interna (GPi) deep brain stimulation (DBS) is an effective treatment for DYT1-associated dystonia, but long-term results are lacking. OBJECTIVE: To evaluate the long-term effects of GPi DBS in patients with DYT1 dystonia. METHODS:: Retrospective chart review (cohort study) of 47 consecutive DYT1+ patients treated by a single surgical team over a 10-year span and followed for up to 96 months (mean: 46 months). Symptom severity was quantified with the Burke-Fahn-Marsden Dystonia Rating Scale (BFMDRS) motor (M) and disability (D) sub-scores. RESULTS: As measured with the BFMDRS (M), symptom severity was reduced to below 20% of baseline after 2 years of DBS therapy (p=.001). The disability scores were reduced to <30% of baseline (p=.001). Symptomatic improvement was durable throughout available follow-up. Sixty-one percent of patients had discontinued all dystonia-related medications at their last follow-up. Ninety-one percent had discontinued at least one class of medication. Infections requiring removal and later reimplantation of hardware occurred in 4/47 (8.5%) patients. Hardware malfunction including lead fractures occurred in 4/47 (8.5%) cases. Lead revision to address poor clinical response occurred in 2 of 92 implanted leads (2.2%). CONCLUSION: GPi DBS is an effective therapy for DYT1-associated torsion dystonia. Statistically significant efficacy is maintained for up to 7 years. Neurologic complications are rare, but long-term hardware-related complications can be significant.