Thalamic Deep Brain Stimulation for Secondary Dystonia in Children and Young Adults

Dystonia is a movement disorder seen in both children and adults that is characterized by "sustained or intermittent muscle contractions causing abnormal, often repetitive, movements, postures, or both." Secondary dystonia is far more common in pediatric populations than primary dystonia, and far more recalcitrant to standard pharmacologic and surgical treatments including Deep Brain Stimulation (DBS). There exists a large unmet need to develop new therapeutics, treatment strategies, and outcome measures for pediatric secondary dystonia. The investigators are proposing to investigate the ventralis oralis posterior nucleus (Vop) of the thalamus as a new target for DBS in secondary dystonia. Prior to the development of DBS, the main surgical treatment of dystonia was thalamotomy. Although there were many different targets in the thalamus, often done in staged procedures, the most common and successful targeted nuclei was the Vop, which is traditionally thought to be the pallidal receiving area. Previous lesioning of Vop produced improvements in dystonia but intolerable side effects, especially when implanted bilaterally. However, given that secondary dystonia patients were often reported to have superior results to primary dystonia it is reasonable to believe that if the side effects can be modulated, that targeting of the Vop nucleus with DBS could be a viable alternative to Globus Pallidus interna (GPi). Given that Deep Brain Stimulation is a treatment that is inherently adjustable, it is conceivable that settings on the Deep Brain Stimulation could be adjusted to allow for clinical benefit with minimal side effects. Indeed, there have been several scattered successful case reports attesting to this possibility.