Globus Pallidus Internus Deep Brain Stimulation as Rescue Therapy for Refractory Dyskinesias following Effective Subthalamic Nucleus Stimulation

Abstract

Background: Deep brain stimulation (DBS) at the subthalamic nucleus (STN) or globus pallidus internus (GPi) can effectively treat the motor symptoms of Parkinson's disease, but dual implantation is rare. We report the first cases of additional GPi stimulation as rescue therapy for disabling dyskinesias following successful STN stimulation. Methods: Two patients, initially treated with bilateral STN DBS, underwent subsequent bilateral GPi DBS after the development of refractory dyskinesias within 1 and 6 years of STN surgery. Patients were evaluated with the Unified Parkinson's Disease Rating Scale (UPDRS) before and after surgeries for STN and GPi DBS. Results: GPi DBS effectively suppressed dyskinesias in these patients and improved their quality of life, as demonstrated by their videos and UPDRS scores. Conclusions: Additional bilateral GPi DBS may be considered in the rare instance of patients who develop refractory dyskinesias early or late after bilateral STN DBS.

Rescue Procedures after Suboptimal Deep Brain Stimulation Outcomes in Common Movement Disorders

“…In certain patients, up titration of dopaminergics in attempts to adequately control breakthrough symptoms can also lead to disabling side effects (neuropsychiatric changes, fatigue, sleep disruption, impulse control disorders, orthostatic hypotension, and dyskinesia among others). Case studies and series have reported using additional leads in the other primary PD DBS target (i.e., STN stimulation to rescue failed GPi stimulation and vice versa) in these circumstances with some success [15,26,27,28,29,30]. …”

“…Published cases where patients underwent GPi stimulation for failed STN stimulation generally report patients with a young age of disease onset (average age 41) and a long interval of success with their initial STN surgery (average of 8 years until rescue surgery) [26,27,29,30]. In all reviewed cases, the reason for failure was disabling dyskinesia or dystonia.…”

“…In all reviewed cases, the reason for failure was disabling dyskinesia or dystonia. Discontinuation of STN stimulation after initiation of GPi stimulation sometimes led to worse control of cardinal motor features, leading to continued STN stimulation in four of seven cases reviewed [26,27,29,30]. Of the seven cases, six achieved a clinically significant benefit with the addition of GPi stimulation [26,27,29,30].…”

“…Discontinuation of STN stimulation after initiation of GPi stimulation sometimes led to worse control of cardinal motor features, leading to continued STN stimulation in four of seven cases reviewed [26,27,29,30]. Of the seven cases, six achieved a clinically significant benefit with the addition of GPi stimulation [26,27,29,30]. Benefits included reduction in the dystonia, dyskinesia, and levodopa equivalent daily dose (i.e., total medication needed) [26,27,29,30].…”

“…Of the seven cases, six achieved a clinically significant benefit with the addition of GPi stimulation [26,27,29,30]. Benefits included reduction in the dystonia, dyskinesia, and levodopa equivalent daily dose (i.e., total medication needed) [26,27,29,30]. …”