title: [3-dimensional position changes of periorbital structures after midface distraction osteogenesis].
abstract: OBJECTIVE
  To evaluate the 3-D position changes of periorbital structures after midface distraction osteogenesis in patients with Crouzon syndrome.
  
  
  METHODS
  The CT data of 8 cases who had accepted the midface distraction osteogenesis following Le Fort III osteotomy were retrospectively analyzed. The patients were averagely 11.9 years old, and the CT was performed before and one year after operation. After 3-D image reconstruction, a right-hand coordinate system based on the preoperational Frankfurt Plane was then established. The pre- and post-operative positions of the superior orbit point (SOr), inferior orbit point (IOr), median orbit point (MOr), lateral orbit point (LOr), anterior ocularis point (AO), ocularis eyeball point (PO) and the four insertion ocularis rectus were documented and compared. The positions of these marked points in normal controls were also documented and compared with those in patients.
  
  
  RESULTS
  After midface distraction osteogenesis, the position of AO was not changed significantly on the y-axis and z-axis, but the distance between two AO points on x-axis was reduced by 3.40 mm; IOr moved averagely 12.24 mm on y-axis and 4.25 mm on z-axis, MOr moved averagely 10.11 mm on y-axis and 2.80 mm on z-axis, LOr moved averagely 9.86 mm on y-axis and 2.31 mm on z-axis. The Inferior Rectus attachment moved averagely 3.63 mm on y-axis and 2.98 mm on z-axis. No other significant change was observed on other marked points.
  
  
  CONCLUSIONS
  Midface distraction osteogenesis following Le Fort III osteotomy can significantly move the medial, lateral and inferior peri-orbital bone structure anteriorly and inferiorly. The eyeballs have no markedly sagittal position changes after distraction except slight medial, downwards movements and anterior-upwards rotations.
authors.affiliation: Department of Plastic and Reconstructive Surgery, Shanghai Ninth People's Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200011, China.
authors.forename: Zhe-Yuan
authors.initials: ZY
authors.lastname: Yu
authors.forename: Xiong-Zheng
authors.initials: XZ
authors.lastname: Mu
authors.forename: Jia-Yi
authors.initials: JY
authors.lastname: Han
mesh_terms: D000293:Adolescent; D002648:Child; D005147:Facial Bones / Q000000981:diagnostic imaging* / Q000601:surgery; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional; D008297:Male; D009915:Orbit / Q000000981:diagnostic imaging*; D019857:Osteogenesis, Distraction / Q000379:methods; D019340:Osteotomy, Le Fort / Q000379:methods; D014057:Tomography, X-Ray Computed