title: Midface advancement in sheep by gradual distraction: a 1-year follow-up study.
abstract: OBJECTIVE
  The purpose of this study was to find a solution to the unsatisfactory postoperative maxillary relapse after major maxillary advancement or inferior repositioning of the maxilla.
  
  
  METHODS
  Major midface advancement by gradual distraction was performed on three young adult sheep over 21 days. Using an external device, the midface was advanced 36 mm in the nasofrontal area and 43 mm in the lateral aspect of the maxilla. The apparatus remained as an external fixation device for 6 weeks after the distraction to allow better ossification. After removal of the device, a 1-year clinical and radiographic follow-up was conducted.
  
  
  RESULTS
  Direct measurements between the markers showed 2- to 3-mm relapse after 1 year. Radiologic measurements demonstrated that the relapse occurred during the first 3 months after removal of the distraction apparatus.
  
  
  CONCLUSIONS
  It was concluded that midface advancement by gradual distraction may obviate the need for bone grafting and offer a greater movement of bone segments with good skeletal stability.
authors.affiliation: Department of Oral and Maxillofacial Surgery, Rambam Medical Center, Haifa, Israel.
authors.forename: A
authors.initials: A
authors.lastname: Rachmiel
authors.forename: I T
authors.initials: IT
authors.lastname: Jackson
authors.forename: Z
authors.initials: Z
authors.lastname: Potparic
authors.forename: D
authors.initials: D
authors.lastname: Laufer
mesh_terms: D000818:Animals; D001852:Bone Lengthening / Q000295:instrumentation / Q000379:methods*; D016267:External Fixators; D008437:Maxilla / Q000601:surgery*; D010012:Osteogenesis; D012008:Recurrence; D012756:Sheep