title: Surgical guide assistant mandibular distraction osteogenesis and sagittal split osteotomy in the treatment of hemifacial microsomia.
abstract: BACKGROUND
  Hemifacial microsomia is the second most common congenital craniofacial malformation after cleft lip/palate with a wide variety of pathologic expression in jaws, skeletal components, ears, and soft tissues. Among the deformities, mandibular hypoplasia is the most common and is the main component that affects facial asymmetry. Mandibular distraction osteogenesis is the mainstay treatment; however, the vector of device and osteotomy lines need to be well designed. We utilized the sagittal split osteotomy for mandibular distraction with rapid prototyping surgical guide plate, making a successful outcome.
  
  
  METHODS
  Hemifacial microsomia with unilateral Pruzansky II mandibular hypoplasia were selected in this study. Three-dimensional CT reconstructive data was put into Proplan CFM for preoperative designing and then manufacturing the surgical guide plate. The mandibular osteotomy and implantation of the internal distractor were performed through an intraoral approach aided with the prefabricated guide plate. Distraction began 7 days postoperation with a frequency of 1 mm/d and the distractor was kept in place 6 to 10 months after the first operation, then the distractor was removed.
  
  
  RESULTS
  From July 2012 to March 2014, 6 cases of Pruzansky II hemifacial microsomia aged from 7 to 11 years were treated with the technique mentioned above. The range of distraction extends from 20 to 30 mm. The facial asymmetry deformities were improved obviously and without any complication.
  
  
  CONCLUSIONS
  Mandibular distraction osteogenesis by sagittal split osteotomy through rapid prototyping surgical guide plate provides certain advantages in the treatment of hemifacial microsomia.
authors.affiliation: From the Department of Maxillofacial Surgery, Plastic Surgery Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.
authors.forename: Lei
authors.initials: L
authors.lastname: Shi
authors.forename: Wei
authors.initials: W
authors.lastname: Liu
authors.forename: Lin
authors.initials: L
authors.lastname: Yin
authors.forename: Shi
authors.initials: S
authors.lastname: Feng
authors.forename: Shuo
authors.initials: S
authors.lastname: Xu
authors.forename: Zhi-Yong
authors.initials: ZY
authors.lastname: Zhang
mesh_terms: D001860:Bone Plates; D002648:Child; D017076:Computer-Aided Design; D005260:Female; D006053:Goldenhar Syndrome / Q000000981:diagnostic imaging / Q000601:surgery*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D021621:Imaging, Three-Dimensional; D008297:Male; D008334:Mandible / Q000000981:diagnostic imaging / Q000601:surgery*; D063168:Mandibular Osteotomy / Q000295:instrumentation* / Q000379:methods*; D003765:Models, Dental; D019857:Osteogenesis, Distraction / Q000295:instrumentation* / Q000379:methods*; D066330:Printing, Three-Dimensional; D025321:Surgery, Computer-Assisted / Q000295:instrumentation*; D014057:Tomography, X-Ray Computed