title: Distraction osteogenesis of the ascending ramus for mandibular hypoplasia using extraoral or intraoral devices: a report of 8 cases.
abstract: OBJECTIVE
  This report presents the results of distraction osteogenesis using unidirectional extraoral and intraoral devices in 8 patients with different grades of vertical mandibular ramus hypoplasia.
  
  
  METHODS
  Eight patients with hypoplastic mandibles underwent unilateral lengthening of the ascending ramus using unidirectional extraoral or intraoral devices. Intraoral mandibular distraction was performed on 5 patients with deficiencies of the vertical ramus up to 24 mm. External devices were used in 3 patients with more severe hypoplasias. An intraoral osteotomy was performed, and progressive distraction at rates of 0.5 mm/12 hours was initiated after 5 days. Once the desired length was reached, the device was maintained in place for 8 to 12 weeks. Three-dimensional computed tomography scans were taken in all the patients to plan the procedure and to compare the changes postoperatively.
  
  
  RESULTS
  Successful distraction osteogenesis was achieved in all patients. The amount of mandibular lengthening ranged from 17 to 32 mm. Complications with the external devices such as rotation of the proximal bony fragment (2 cases) and loosening of the external screws at the end of the consolidation period (1 case) were observed.
  
  
  CONCLUSIONS
  The results suggest that the intraoral device can be used as the method of choice for distraction osteogenesis of the ascending ramus of the mandible in patients with large deficiencies. Preoperative and postoperative 3-dimensional computed tomographic scans are essential in treatment planning.
authors.affiliation: Department of Oral and Maxillofacial Surgery, Hospital Universitario de la Princesa, Madrid, Spain. piluca10@jazzfree.com
authors.forename: P
authors.initials: P
authors.lastname: Rubio-Bueno
authors.forename: A
authors.initials: A
authors.lastname: Padrón
authors.forename: E
authors.initials: E
authors.lastname: Villa
authors.forename: F J
authors.initials: FJ
authors.lastname: Díaz-González
mesh_terms: D001863:Bone Screws; D002648:Child; D016267:External Fixators; D005146:Facial Asymmetry / Q000601:surgery*; D005260:Female; D006801:Humans; D016268:Internal Fixators; D008297:Male; D008334:Mandible / Q000002:abnormalities / Q000000981:diagnostic imaging / Q000601:surgery*; D008865:Microstomia / Q000601:surgery; D019647:Oral Surgical Procedures / Q000295:instrumentation*; D019857:Osteogenesis, Distraction / Q000295:instrumentation*; D010027:Osteotomy / Q000295:instrumentation; D011859:Radiography; D016896:Treatment Outcome