title: Constant-Current Deep Brain Stimulation of the Globus Pallidus Internus in the Treatment of Primary Dystonia by a Novel 8-Contact (Octrode) Lead.
abstract: OBJECTIVE
  To evaluate bilateral constant-current globus pallidus internus (GPi) deep brain stimulation using an 8-contact lead.
  
  
  METHODS
  This prospective, open-label, single-center pilot study of 10 patients assessed the feasibility of delivering bilaterally constant-current GPi deep brain stimulation with a novel 8-channel lead to treat primary dystonia using standard scales as outcome measures.
  
  
  RESULTS
  Patients included 4 men and 6 women with a mean age of 35.8 years ± 9.2 (range, 27-49 years). Mean age of onset was 18.5 years ± 9.1 (range, 8-35 years), and mean disease duration was 17.3 years (range, 7-27 years). All had primary dystonia (8 generalized dystonia, 1 segmental dystonia, 1 focal dystonia). The primary variable was determined as 50% reduction in dystonia symptoms from baseline to the 6-month follow-up, as defined by the Burke-Fahn-Marsden Dystonia Rating Scale. Six patients (60.0%) achieved >50% reduction in Burke-Fahn-Marsden Dystonia Rating Scale score and were classified as responders at the 6-month follow-up. Five of these 6 responders (83.3%) sustained that response through the assessment at the end of the first year. Constant-current stimulation was associated with significant improvement in pain and quality of life in all patients. Nearly 84% of the overall improvement occurred by the end of first month after stimulation onset, documenting an early response to treatment. Axial symptoms responded the best.
  
  
  CONCLUSIONS
  Constant-current GPi deep brain stimulation proved safe and efficacious for treatment of primary dystonia. Motor scores improved by 54%, mostly within the first month. No phenotype-specific stimulation could be achieved, despite the capability of the new lead to stimulate specific loci within the GPi.
authors.affiliation: Unit of Stereotactic and Functional Neurosurgery, Department of Neurosurgery, University of Athens Medical School, Athens, Greece; "Petros S. Kokkalis" Hellenic Center for Neurosurgical Research, Athens, Greece.
authors.forename: Damianos E
authors.initials: DE
authors.lastname: Sakas
authors.affiliation: "Petros S. Kokkalis" Hellenic Center for Neurosurgical Research, Athens, Greece.
authors.forename: Athanassios
authors.initials: A
authors.lastname: Leonardos
authors.affiliation: Unit of Stereotactic and Functional Neurosurgery, Department of Neurosurgery, University of Athens Medical School, Athens, Greece; "Petros S. Kokkalis" Hellenic Center for Neurosurgical Research, Athens, Greece.
authors.forename: Efstathios
authors.initials: E
authors.lastname: Boviatsis
authors.affiliation: Unit of Stereotactic and Functional Neurosurgery, Department of Neurosurgery, University of Athens Medical School, Athens, Greece.
authors.forename: Stergios
authors.initials: S
authors.lastname: Gatzonis
authors.affiliation: Unit of Stereotactic and Functional Neurosurgery, Department of Neurosurgery, University of Athens Medical School, Athens, Greece; "Petros S. Kokkalis" Hellenic Center for Neurosurgical Research, Athens, Greece.
authors.forename: Ioannis
authors.initials: I
authors.lastname: Panourias
authors.affiliation: Unit of Stereotactic and Functional Neurosurgery, Department of Neurosurgery, University of Athens Medical School, Athens, Greece.
authors.forename: Pantelis
authors.initials: P
authors.lastname: Stathis
authors.affiliation: Unit of Stereotactic and Functional Neurosurgery, Department of Neurosurgery, University of Athens Medical School, Athens, Greece; "Petros S. Kokkalis" Hellenic Center for Neurosurgical Research, Athens, Greece. Electronic address: mplam@hotmail.com.
authors.forename: Lampis C
authors.initials: LC
authors.lastname: Stavrinou
mesh_terms: D000328:Adult; D046690:Deep Brain Stimulation / Q000295:instrumentation / Q000379:methods*; D020821:Dystonic Disorders / Q000628:therapy*; D004567:Electrodes, Implanted; D005260:Female; D005917:Globus Pallidus; D006801:Humans; D008297:Male; D008875:Middle Aged; D010865:Pilot Projects; D011446:Prospective Studies; D011788:Quality of Life; D016896:Treatment Outcome
keywords: Constant-current stimulation; Deep brain stimulation; Dystonia; Globus pallidus; Octrode