"Rescue" of bilateral subthalamic stimulation by bilateral pallidal stimulation: case report

Deep brain stimulation (DBS) of the subthalamic nucleus (STN) orglobus pallidus pars interna (GPi) is well established as a treatment for advanced Parkinson's disease. In general, one of the 2 targets is chosen based on the clinical features of each patient. Stimulation of both targets could be viewed as redundant, given that the 2 targets are directly connected. However, it is possible that each target has different mechanisms, with clinical effects mediated by orthodromic or antidromic stimulation. The authors report the case of a patient with severe Parkinson's disease who had previously undergone bilateral subthalamic stimulation with excellent benefits. However, he presented with significant worsening associated with disease progression and pharmacological treatment, and then underwent bilateral GPi DBS. Follow-up assessment was conducted clinically as well as through blinded ratings of video recordings. Pallidal DBS may be a safe and useful strategy to manage dystonic features and behavioral complications of subthalamic stimulation and pharmacological management. While combined stimulation was quite successful in the reported patient, further studies with larger samples and longer follow-up periods will be necessary before recommending the addition of pallidal DBS as a routine strategy for patients previously implanted with STN DBS.