title: Posterior mandibular widening secondary to advancement sagittal split osteotomy: A retrospective study.
abstract: BACKGROUND
  Patients sometimes spontaneously report a modification of the width of their lower face after an advancement bilateral sagittal split osteotomy (ABSSO). The main goal of our study was to assess the variation of the bigonial distance (BGD) before and after ABSSO in a group of patients. The second goal was to look for a possible relation between the variation of BGD and the amount of mandibular advancement.
  
  
  METHODS
  We conducted a retrospective radiological study on patients who underwent an isolated ABSSO (Obwegeser-Dal Pont II type osteotomy) for a class II malocclusion in our department over a 26 months period. The measures were made on standardized frontal and lateral teleradiographies taken before, one day and one year postoperatively.
  
  
  RESULTS
  Fifty patients (36 females, 14 males; mean age: 24) could be included. BGD was significantly increased one day (+9.8mm, P<10(-3)) and one year after surgery (+4mm, P<10(-3)). There was no relation between the amount of mandibular advancement and the increase of BGD.
  
  
  CONCLUSIONS
  Our results suggest that ABSSO is responsible for posterior mandibular enlargement which must be taken into account during the aesthetic preoperative assessment. Further studies are mandatory to identify the risk factors for this phenomenon.
authors.affiliation: Department of maxillofacial surgery, hospices civils de Lyon, hôpital Lyon-Sud, Claude-Bernard Lyon I university, chemin du Grand-Revoyet, 69495 Pierre-Bénite, France. Electronic address: n.sigaux@gmail.com.
authors.forename: N
authors.initials: N
authors.lastname: Sigaux
authors.affiliation: Department of maxillofacial surgery, hospices civils de Lyon, hôpital Lyon-Sud, Claude-Bernard Lyon I university, chemin du Grand-Revoyet, 69495 Pierre-Bénite, France.
authors.forename: M
authors.initials: M
authors.lastname: Lahon
authors.affiliation: Biostatistics, hospices civils de Lyon, National Center for Scientific Research (CNRS - UMR 5558), Claude-Bernard Lyon I university, chemin du Grand-Revoyet, 69495 Pierre-Bénite, France.
authors.forename: D
authors.initials: D
authors.lastname: Maucort-Boulch
authors.affiliation: Department of maxillofacial surgery, hospices civils de Lyon, hôpital Lyon-Sud, Claude-Bernard Lyon I university, chemin du Grand-Revoyet, 69495 Pierre-Bénite, France.
authors.forename: P
authors.initials: P
authors.lastname: Bouletreau
mesh_terms: D000293:Adolescent; D000328:Adult; D002508:Cephalometry; D005145:Face / Q000473:pathology / Q000601:surgery; D005260:Female; D006801:Humans; D008297:Male; D008312:Malocclusion, Angle Class II / Q000473:pathology / Q000601:surgery; D008334:Mandible / Q000473:pathology / Q000601:surgery*; D019186:Mandibular Advancement / Q000379:methods*; D019340:Osteotomy, Le Fort / Q000379:methods*; D012189:Retrospective Studies; D055815:Young Adult
keywords: Avancement mandibulaire; Chirurgie orthognatique; Mandibular advancement; Orthognathic surgery