title: Alleviation of off-period dystonia in Parkinson disease by a microlesion following subthalamic implantation.
abstract: OBJECTIVE
  A collision/implantation or microlesion effect is commonly described after subthalamic nucleus (STN) implantation for high-frequency stimulation, and this is presumed to reflect disruption of cells and/or fibers. Off-period dystonia, a frequent cause of disability in patients with advanced Parkinson disease, can lead to the need for surgical treatment. The authors assessed the early effect of this microlesion on off-period dystonia.
  
  
  METHODS
  The authors assessed 30 consecutive patients with the advanced levodopa-responsive form of Parkinson disease. The patients' symptoms were Hoehn and Yahr Scale score > or = 3, the mean duration of their disease was 11.4 +/- 3.5 years, and they had undergone bilateral implantation of electrodes within the STN for high-frequency stimulation between February 2004 and December 2006. The microlesion effect was defined by the clinical improvement (Unified Parkinson's Disease Rating Scale [UPDRS] Part III score, UPDRS Part IV, item 35) assessed the morning of the 3rd day following STN implantation, after at least a 12-hour withdrawal of dopaminergic treatment and before the programmable pulse generator was switched on (off-drug/off-stimulation mode).
  
  
  RESULTS
  Compared with baseline (off state), the microlesion effect improved the motor score (UPDRS Part III) by 27%. Subscores for tremor, rigidity, and bradykinesia respectively improved by 42, 37, and 25%. Nineteen patients (63%) suffered from off-period dystonia before surgery. Twelve (41%) reported complete relief of their symptoms in the immediate postoperative period and remained free of painful off-period dystonia throughout the 6-month follow-up period.
  
  
  CONCLUSIONS
  The author postulated that off-period dystonia alleviation may reflect both a microsubthalamotomy and micropallidotomy effect. They hypothesize, moreover, that the microlesion could play a role in the 6-month postoperative outcome.
authors.affiliation: Department of Neurosurgery, Rouen University Hospital and University of Rouen, France. david.maltete@chu-rouen.fr
authors.forename: Stéphane
authors.initials: S
authors.lastname: Derrey
authors.forename: Romain
authors.initials: R
authors.lastname: Lefaucheur
authors.forename: Nathalie
authors.initials: N
authors.lastname: Chastan
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Gérardin
authors.forename: Didier
authors.initials: D
authors.lastname: Hannequin
authors.forename: Marie
authors.initials: M
authors.lastname: Desbordes
authors.forename: David
authors.initials: D
authors.lastname: Maltête
mesh_terms: D000328:Adult; D000368:Aged; D046690:Deep Brain Stimulation / Q000379:methods*; D004421:Dystonia / Q000503:physiopathology / Q000628:therapy*; D004567:Electrodes, Implanted; D005260:Female; D005500:Follow-Up Studies; D005917:Globus Pallidus / Q000503:physiopathology* / Q000601:surgery*; D006801:Humans; D008297:Male; D008866:Microsurgery; D008875:Middle Aged; D009460:Neurologic Examination; D010300:Parkinson Disease / Q000503:physiopathology / Q000628:therapy*; D020531:Subthalamic Nucleus / Q000503:physiopathology* / Q000601:surgery*; D016896:Treatment Outcome