title: Pedunculopontine Nucleus Region Deep Brain Stimulation in Parkinson Disease: Surgical Anatomy and Terminology.
abstract: Several lines of evidence over the last few years have been important in ascertaining that the pedunculopontine nucleus (PPN) region could be considered as a potential target for deep brain stimulation (DBS) to treat freezing and other problems as part of a spectrum of gait disorders in Parkinson disease and other akinetic movement disorders. Since the introduction of PPN DBS, a variety of clinical studies have been published. Most indicate improvements in freezing and falls in patients who are severely affected by these problems. The results across patients, however, have been variable, perhaps reflecting patient selection, heterogeneity in target selection and differences in surgical methodology and stimulation settings. Here we outline both the accumulated knowledge and the domains of uncertainty in surgical anatomy and terminology. Specific topics were assigned to groups of experts, and this work was accumulated and reviewed by the executive committee of the working group. Areas of disagreement were discussed and modified accordingly until a consensus could be reached. We demonstrate that both the anatomy and the functional role of the PPN region need further study. The borders of the PPN and of adjacent nuclei differ when different brainstem atlases and atlas slices are compared. It is difficult to delineate precisely the PPN pars dissipata from the nucleus cuneiformis, as these structures partially overlap. This lack of clarity contributes to the difficulty in targeting and determining the exact localization of the electrodes implanted in patients with akinetic gait disorders. Future clinical studies need to consider these issues.
authors.affiliation: Division of Neurosurgery, Toronto Western Hospital, University of Toronto, Toronto, Ont., Canada.
authors.forename: Clement
authors.initials: C
authors.lastname: Hamani
authors.forename: Tipu
authors.initials: T
authors.lastname: Aziz
authors.forename: Bastiaan R
authors.initials: BR
authors.lastname: Bloem
authors.forename: Peter
authors.initials: P
authors.lastname: Brown
authors.forename: Stephan
authors.initials: S
authors.lastname: Chabardes
authors.forename: Terry
authors.initials: T
authors.lastname: Coyne
authors.forename: Kelly
authors.initials: K
authors.lastname: Foote
authors.forename: Edgar
authors.initials: E
authors.lastname: Garcia-Rill
authors.forename: Etienne C
authors.initials: EC
authors.lastname: Hirsch
authors.forename: Andres M
authors.initials: AM
authors.lastname: Lozano
authors.forename: Paolo A M
authors.initials: PA
authors.lastname: Mazzone
authors.forename: Michael S
authors.initials: MS
authors.lastname: Okun
authors.forename: William
authors.initials: W
authors.lastname: Hutchison
authors.forename: Peter
authors.initials: P
authors.lastname: Silburn
authors.forename: Ludvic
authors.initials: L
authors.lastname: Zrinzo
authors.forename: Mesbah
authors.initials: M
authors.lastname: Alam
authors.forename: Laurent
authors.initials: L
authors.lastname: Goetz
authors.forename: Erlick
authors.initials: E
authors.lastname: Pereira
authors.forename: Anand
authors.initials: A
authors.lastname: Rughani
authors.forename: Wesley
authors.initials: W
authors.lastname: Thevathasan
authors.forename: Elena
authors.initials: E
authors.lastname: Moro
authors.forename: Joachim K
authors.initials: JK
authors.lastname: Krauss
mesh_terms: D046690:Deep Brain Stimulation / Q000379:methods*; D006801:Humans; D010300:Parkinson Disease / Q000175:diagnosis / Q000601:surgery*; D045042:Pedunculopontine Tegmental Nucleus / Q000033:anatomy & histology* / Q000601:surgery*; D009626:Terminology as Topic