title: Deep brain stimulator electrodes used for lesioning: proof of principle.
abstract: OBJECTIVE
  Patients with chronically implanted deep brain stimulator (DBS) electrodes can encounter complications requiring hardware removal. We assessed the safety and efficacy of using implanted DBS electrodes to create a therapeutic lesion before their removal.
  
  
  METHODS
  Revision or removal of the DBS electrodes was required in two patients who had previously undergone DBS implantation. We conducted a series of in vitro experiments to confirm that the DBS electrodes could be used to generate radiofrequency lesions and to assess the relationship between radiofrequency parameters and lesion size. With this information, and with the approval of the hospital ethical review board, implanted electrodes were used to create incremental radiofrequency lesions in the thalamus in one patient and in the subthalamic nucleus in another. The procedures were performed under local anesthesia with contiguous contacts of the DBS lead connected to the active and reference sites of the RF generator to create a bipolar lesion.
  
  
  RESULTS
  A 51-year-old man with essential tremor and a thalamic DBS required repeated battery changes secondary to tolerance and high voltage demands. Rather than replacing the battery, a radiofrequency thalamotomy was performed by using the existing left DBS electrode. At the 6-month follow-up examination, successful lesioning provided near complete tremor control. A second patient, a 50-year-old man with Parkinson's disease who had undergone bilateral subthalamic deep brain stimulation, developed skin erosion over the DBS hardware. A subthalamic nucleus lesion was made through the right DBS electrode. Lesion position and size were confirmed with magnetic resonance imaging.
  
  
  CONCLUSIONS
  Lesions can be made through chronically implanted DBS electrodes in a safe, graded fashion and can produce therapeutic benefit.
authors.affiliation: Division of Neurosurgery, Toronto Western Hospital, University of Toronto, Ontario, Canada.
authors.forename: M Y
authors.initials: MY
authors.lastname: Oh
authors.forename: M
authors.initials: M
authors.lastname: Hodaie
authors.forename: S H
authors.initials: SH
authors.lastname: Kim
authors.forename: A
authors.initials: A
authors.lastname: Alkhani
authors.forename: A E
authors.initials: AE
authors.lastname: Lang
authors.forename: A M
authors.initials: AM
authors.lastname: Lozano
mesh_terms: D020878:Device Removal; D004529:Egg White / Q000528:radiation effects; D004599:Electric Stimulation Therapy / Q000295:instrumentation*; D004566:Electrodes; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D010300:Parkinson Disease / Q000175:diagnosis / Q000628:therapy*; D016634:Radiosurgery / Q000295:instrumentation* / Q000379:methods*; D020531:Subthalamic Nucleus / Q000601:surgery; D013788:Thalamus / Q000601:surgery; D016896:Treatment Outcome; D014202:Tremor / Q000175:diagnosis / Q000628:therapy*