title: Dual midfacial distraction osteogenesis for Crouzon syndrome: long-term follow-up study for relapse and growth.
abstract: OBJECTIVE
  Rigid external distraction osteogenesis is regarded as a standard treatment for congenital midfacial hypoplasia. However, external distraction for the upper portion of the midface is not as effective and tends to rotate the midfacial segment in a counterclockwise direction. Moreover, patients poorly tolerate it because of the device's bulkiness. To prevent such drawbacks of an external distractor, both external and internal distractors were synchronously applied to patients with Crouzon syndrome.
  
  
  METHODS
  In 6 patients with Crouzon syndrome in whom a dual-distraction technique was applied, distraction of the midfacial region was performed for up to a mean length of 15.3 mm. The external distractor was removed after a 1-month consolidation period, but the internal distractor was maintained for more than 6 months. The degree of advancement of the midface and ossification was measured with lateral cephalometry and 3-dimensional computed tomography imaging, respectively.
  
  
  RESULTS
  At long-term follow-up (mean, 4.6 years), the facial contours retained the initial distraction geometry with almost no relapse, showing that the ideal facial contour and occlusion could be obtained. Bone deposition was found to be continually progressing even 6 months postoperatively, and more than 6 months of consolidation was required for complete ossification that mainly occurred in the pterygomaxillary junction and lateral orbital wall.
  
  
  CONCLUSIONS
  The dual-distraction technique can induce balanced growth without the recurrence of hypoplasia, and it may eventually yield satisfactory outcomes in Crouzon syndrome.
authors.affiliation: Department of Plastic and Reconstructive Surgery, Yonsei University Health System, Severance Hospital, Seoul, Republic of Korea.
authors.forename: Dong Won
authors.initials: DW
authors.lastname: Lee
authors.forename: Ki Weon
authors.initials: KW
authors.lastname: Ham
authors.forename: Soon Man
authors.initials: SM
authors.lastname: Kwon
authors.forename: Dae Hyun
authors.initials: DH
authors.lastname: Lew
authors.forename: Eul Je
authors.initials: EJ
authors.lastname: Cho
mesh_terms: D000293:Adolescent; D002508:Cephalometry; D002648:Child; D003394:Craniofacial Dysostosis / Q000601:surgery*; D016267:External Fixators; D005147:Facial Bones / Q000254:growth & development* / Q000601:surgery; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D016268:Internal Fixators; D008297:Male; D008445:Maxillofacial Development; D019857:Osteogenesis, Distraction / Q000295:instrumentation / Q000379:methods*; D012189:Retrospective Studies; D055502:Secondary Prevention; D016896:Treatment Outcome