22 GPi Deep Brain Stimulation after STN DBS: Cases report

Abstract

Deep Brain Stimulation (DBS) is the surgical procedure of choice in advanced patients with Parkinson’s disease (PD) complicated by motor fluctuations. The subthalamic nucleus (STN) and the globus pallidus internal (GPi) are the two most common targets used to treat PD. Anyway the most source of information about the efficacy of this procedure came from STN DBS. Only recently the comparison between GPi and STN DBS in advanced PD had shown in 24 months follow-up study similar improvement in motor score; GPi DBS also improved depression while in STN patients it worsened, finally the reduction of dopaminergic therapy was higher in STN DBS patients [1]. Experiences of simultaneous stimulation of both STN and GPi are inconclusive and limited in literature [2,3]. The long term follow-up at 4, 8 and recently at 9 years after STN DBS shows that while the improvement of levodopa induced motor complications are maintained, freezing, postural instability, falling, speech difficulties and cognitive impairment emerge as the major source of disability [4–6]. Nevertheless the information emerging from latter studies, some patients manifest a motor disease progression need increasing dopaminergic doses after many years of STN DBS. In some of these cases continuous infusion of Duodopa is reported as possible therapeutic strategy [7]. We describe three patients (Table) with severe functional impairment after 8 year with STN DBS in whom GPi implant has been done as “rescue therapy”.