title: Five year follow-up of mandibular distraction osteogenesis on the dentofacial structures of syndromic children.
abstract: OBJECTIVE
  To determine long-term treatment outcomes of mandibular distraction osteogenesis (DO) in syndromic children with severely hypoplastic lower jaws.
  
  
  METHODS
  Descriptive clinical study.
  
  
  METHODS
  Cleft Palate and Craniofacial Centre, Department of Plastic Surgery, Helsinki University Central Hospital. Ten children (mean age 7.6 years) with various syndromes (craniofacial microsomia, Treacher Collins syndrome, Nager syndrome).
  
  
  METHODS
  Ten growing children with severely retrognathic lower jaws were distracted with an extraoral bicortically fixed DO device (mean, 34 days) followed by a consolidation period (mean, 9 weeks). Orthodontic treatment was performed pre- and/or postoperatively with fixed or functional appliances (mean 14 months).
  
  
  METHODS
  The landmarks on standard lateral cephalometric X-rays were digitized and angular and linear measurements were compared using Student's t-test to assess changes in pre-distraction, post-distraction, post-consolidation and 1 year follow-up. Long-term follow-up (2 and 5 years) was interpreted according to mean values.
  
  
  RESULTS
  The measurements of SNB, ANB, facial convexity angle, overjet and overbite, and soft tissue facial profile showed significant correction of the mandibular retrognathia and malocclusion. The mandibular divergence decreased and mandibular, corpus, and ramus lengths remained stable during the consolidation period. The regression of mandibular measurements towards pre-distraction values was observed in skeletal and dental parameters and soft tissue profiles during the first postoperative year and continued during the 2- to 5-year follow-up period. The achieved mandibular corpus and ramus lengthening was stable while the mandible displayed considerable posterior rotation but no further growth. Orthodontic treatment could not overcome the regression of mandibular measurements to their original values. The maxilla continued its normal growth during the long-term follow-up. Two patients had tracheostomies, but the tube was removed from both during or immediately after distraction. CONCLUSION - Excellent short-term structural results of mandibular DO are not stable during the growth of syndromic children because of restricted mandibular growth. Thus, a re-evaluation of DO timing in the improvement of facial aesthetics must be considered. However, mandibular DO in children with severe airway problems is recommended.
authors.affiliation: Cleft Palate and Craniofacial Centre, Department of Plastic Surgery, Helsinki University Central Hospital, Helsinki, Finland.
authors.forename: S
authors.initials: S
authors.lastname: Gürsoy
authors.forename: J
authors.initials: J
authors.lastname: Hukki
authors.forename: K
authors.initials: K
authors.lastname: Hurmerinta
mesh_terms: D002508:Cephalometry / Q000379:methods; D002648:Child; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008334:Mandible / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery*; D019857:Osteogenesis, Distraction / Q000295:instrumentation / Q000379:methods*; D011859:Radiography; D012008:Recurrence; D063173:Retrognathia / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery*; D013577:Syndrome; D016896:Treatment Outcome