title: The clinical utility of botulinum toxin injections targeted at the motor endplate zone in cervical dystonia.
abstract: OBJECTIVE
  Cervical dystonia (CD) patients usually receive repeated botulinum neurotoxin (BoNT) injections. The aims of this study were to evaluate the feasibility of motor endplate zone (MEZ) detection of relevant cervical muscles in CD patients receiving chronic BoNT treatment and to compare the treatment effect of half-dosed, endplate-targeted injections to standard BoNT injections.
  
  
  METHODS
  In study 1, high-density surface electromyography (HD-sEMG) was recorded from the sternocleidomastoid (SCM) and splenius capitis (SC) muscles in 18 CD patients with ongoing BoNT treatment, by which the location of the MEZ was determined. In study 2, nine additional patients with rotational-type CD participated in a treatment effect study where they received either half of their regular BoNT dose through endplate-targeted injections or their normal BoNT dose through standard injections (crossover design). Dystonia severity was recorded before and 4 weeks after each treatment session (Toronto Western Spasmodic Torticollis Rating Scale severity subscore).
  
  
  RESULTS
  In the SCM muscle the MEZ was located at the lower border of the superior third part of the muscle, and in the SC muscle at half muscle length. Endplate-targeted, half-dosed BoNT injection resulted in a similar treatment effect to injecting the full dose in the standard technique.
  
  
  CONCLUSIONS
  Half-dosed, endplate-targeted BoNT injections lead to a similar treatment effect to the standard BoNT injection protocol. MEZ detection confronts the clinician with some technical challenges, such as the ability of accurate and technically optimal placement of the electrode grid and correct interpretation of the HD-sEMG signal.
authors: Department of Neurology, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Centre, Nijmegen, The Netherlands.
authors: C C S
authors: CC
authors: Delnooz
authors: L C
authors: LC
authors: Veugen
authors: J W
authors: JW
authors: Pasman
authors: B G
authors: BG
authors: Lapatki
authors: J P
authors: JP
authors: van Dijk
authors: B P C
authors: BP
authors: van de Warrenburg
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019274:Botulinum Toxins, Type A / Q000008:administration & dosage* / Q000494:pharmacology; D004421:Dystonia / Q000151:congenital; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009045:Motor Endplate / Q000187:drug effects*; D009334:Neck Muscles / Q000187:drug effects*; D009465:Neuromuscular Agents / Q000008:administration & dosage* / Q000494:pharmacology; D014103:Torticollis / Q000151:congenital* / Q000188:drug therapy; D016896:Treatment Outcome
chemical_list: D009465:Neuromuscular Agents; D019274:Botulinum Toxins, Type A; C545476:incobotulinumtoxinA
keywords: botulinum toxin; cervical dystonia; electromyography; motor endplate zone