title: Postsurgical stability of oropharyngeal airway changes following counter-clockwise maxillo-mandibular advancement surgery.
abstract: OBJECTIVE
  This study evaluated oropharyngeal airway changes and stability following surgical counter-clockwise rotation and advancement of the maxillo-mandibular complex.
  
  
  METHODS
  Fifty-six adults (48 females, 8 males), between 15 and 51 years of age, were treated with Le Fort I osteotomies and bilateral mandibular ramus sagittal split osteotomies to advance the maxillo-mandibular complex with a counter-clockwise rotation. The average postsurgical follow-up was 34 months. Each patient's lateral cephalograms were traced, digitized twice, and averaged to estimate surgical changes (T2-T1) and postsurgical changes (T3-T2).
  
  
  RESULTS
  During surgery, the occlusal plane angle decreased significantly (8.6 +/- 5.8 degrees ) and the maxillo-mandibular complex advanced and rotated counter-clockwise. The maxilla moved forward (2.4 +/- 2.7 mm) at ANS and the mandible was advanced 13.1 +/- 5.1 mm at menton, 10 +/- 4.4 mm at point B, and 6.9 +/- 3.7 mm at lower incisor edge. Postsurgical hard tissue changes were not statistically significant. While the upper oropharyngeal airway decreased significantly (4.2 +/- 3.4 mm) immediately after surgery, the narrowest retropalatal, lowest retropalatal airway, and the narrowest retroglossal airway measurements increased 2.9 +/- 2.7, 3.7 +/- 3.2, and 4.4 +/- 4.4 mm, respectively. Over the average 34 months postsurgical period, upper retropalatal airway increased 3.9 +/- 3.7 mm, while narrowest retropalatal, lowest retropalatal airway, and narrowest retroglossal airway remained stable. Head posture showed flexure immediately after surgery (4.8 +/- 5.9 degrees ) and extension postsurgically (1.6 +/- 5.6 degrees ).
  
  
  CONCLUSIONS
  Maxillo-mandibular advancement with counter-clockwise rotation produces immediate increases in middle and lower oropharyngeal airway dimensions, which were constrained by changes in head posture but remain stable over the postsurgical period. The upper oropharyngeal airway space increased only on the longest follow-up.
authors.affiliation: Orthodontics, UNESP-Paulista State University, Sao Paulo, Brazil.
authors.forename: Joao Roberto
authors.initials: JR
authors.lastname: Goncalves
authors.forename: Peter H
authors.initials: PH
authors.lastname: Buschang
authors.forename: Daniela Godoi
authors.initials: DG
authors.lastname: Goncalves
authors.forename: Larry M
authors.initials: LM
authors.lastname: Wolford
mesh_terms: D000293:Adolescent; D000328:Adult; D000403:Airway Resistance; D002508:Cephalometry; D005260:Female; D006801:Humans; D008297:Male; D008313:Malocclusion, Angle Class III / Q000601:surgery*; D019186:Mandibular Advancement / Q000379:methods*; D008437:Maxilla / Q000601:surgery*; D019767:Maxillofacial Abnormalities / Q000601:surgery*; D008875:Middle Aged; D009960:Oropharynx / Q000033:anatomy & histology*; D019340:Osteotomy, Le Fort / Q000379:methods*; D012189:Retrospective Studies; D018709:Statistics, Nonparametric; D016896:Treatment Outcome