title: Muscle histopathology in children with spastic cerebral palsy receiving botulinum toxin type A.
abstract: BACKGROUND
  Botulinum toxin A (BoNTA) is routine treatment for hypertonicity in children with cerebral palsy (CP).
  
  
  METHODS
  This single-blind, prospective, cross-sectional study of 10 participants (mean age 11 years 7 months) was done to determine the relationship between muscle histopathology and BoNTA in treated medial gastrocnemius muscle of children with CP. Open muscle biopsies were taken from medial gastrocnemius muscle and vastus lateralis (control) during orthopedic surgery.
  
  
  RESULTS
  Neurogenic atrophy in the medial gastrocnemius was seen in 6 participants between 4 months and 3 years post-BoNTA. Type 1 fiber loss with type 2 fiber predominance was significantly related to the number of BoNTA injections (r = 0.89, P < 0.001).
  
  
  CONCLUSIONS
  The impact of these changes in muscle morphology on muscle function in CP is not clear. It is important to consider rotating muscle selection or injection sites within the muscle or allowing longer time between injections.
authors.affiliation: Department of Paediatric Rehabilitation, Princess Margaret Hospital, Perth, Western Australia, Australia.|School of Paediatrics and Child Health, University of Western Australia, Perth, Western Australia, Australia.
authors.forename: Jane
authors.initials: J
authors.lastname: Valentine
authors.affiliation: Department of Orthopedic Surgery, Princess Margaret Hospital, Perth, Western Australia, Australia.
authors.forename: Katherine
authors.initials: K
authors.lastname: Stannage
authors.affiliation: Neuropathology Section, Royal Perth Hospital, Perth, Western Australia, Australia.
authors.forename: Vicki
authors.initials: V
authors.lastname: Fabian
authors.affiliation: Neuropathology Section, Royal Perth Hospital, Perth, Western Australia, Australia.
authors.forename: Kevin
authors.initials: K
authors.lastname: Ellis
authors.affiliation: School of Sport Science, Exercise & Health, University of Western Australia, Perth, Western Australia, Australia.
authors.forename: Siobhan
authors.initials: S
authors.lastname: Reid
authors.affiliation: School of Sport Science, Exercise & Health, University of Western Australia, Perth, Western Australia, Australia.
authors.forename: Christian
authors.initials: C
authors.lastname: Pitcher
authors.affiliation: Department of Paediatric Rehabilitation, Princess Margaret Hospital, Perth, Western Australia, Australia.|Faculty of Health Science, Curtin University, Perth, Western Australia, Australia.
authors.forename: Catherine
authors.initials: C
authors.lastname: Elliott
mesh_terms: D019274:Botulinum Toxins, Type A / Q000627:therapeutic use*; D002547:Cerebral Palsy / Q000188:drug therapy*; D002648:Child; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D008854:Microscopy, Electron; D018482:Muscle, Skeletal / Q000187:drug effects / Q000473:pathology* / Q000648:ultrastructure; D009465:Neuromuscular Agents / Q000627:therapeutic use*; D015203:Reproducibility of Results; D016037:Single-Blind Method
chemical_list: D009465:Neuromuscular Agents; D019274:Botulinum Toxins, Type A
keywords: botulinum toxin; cerebral palsy; hypertonia; medial gastrocnemius; muscle histopathology; neurogenic atrophy