title: Precision of Le Fort I osteotomy: planning versus outcome. A multi-centre retrospective study.
abstract: The purpose of this study was to evaluate the accuracy of Le Fort I surgery by comparing planned surgical movements with actual outcomes.
  
  
  
  A minimum number of seven consecutive cases that had undergone a Le Fort I osteotomy procedure alone or in combination with a mandibular osteotomy from six different hospital units in the East of England between 2009 and 2010 were identified. A total of 56 cases met the inclusion criteria where surgical splints were used and model surgery had been performed. Pre- and post-operative lateral cephalograms were digitised using Dolphin©imaging software (Version 10.0) and three cephalometric points were assessed to measure precision of surgical movements: A point (A-pt); Upper incisor tip (U1 tip); and Upper first molar occlusal point (U6 occ). The final position of the maxilla was compared to the planned position.
  
  
  
  In 71% of cases surgical movements were within 2 mm and 20% of this group were within 1 mm of the predicted position. The mean accuracy was 1.39 mm (SD 0.92 mm) for the former and 0.78 mm (SD 0.58 mm) for the latter. Accuracy correlated negatively with increased surgical complexity, particularly posterior differential impactions of the maxilla. There was no statistically significant difference between centres.
  
  
  
  Pre-operative surgical planning of Le Fort I osteotomies was generally accurate. This study demonstrates that different operators across six centres produced consistent surgical outcomes and this confirms previously reported data.
authors.affiliation: a Department of Orthodontics , Guy's and St Thomas' NHS Foundation Trust , London , UK.
authors.forename: Stefan
authors.initials: S
authors.lastname: Abela
authors.affiliation: b Norfolk and Norwich University Hospital NHS Foundation Trust , Norwich , UK.
authors.forename: David
authors.initials: D
authors.lastname: Tewson
authors.affiliation: b Norfolk and Norwich University Hospital NHS Foundation Trust , Norwich , UK.
authors.forename: Sharon
authors.initials: S
authors.lastname: Prince
authors.affiliation: c University of Bristol , Bristol , UK.
authors.forename: Martyn
authors.initials: M
authors.lastname: Sherriff
authors.affiliation: a Department of Orthodontics , Guy's and St Thomas' NHS Foundation Trust , London , UK.
authors.forename: Dirk
authors.initials: D
authors.lastname: Bister
mesh_terms: D002508:Cephalometry; D008437:Maxilla; D019340:Osteotomy, Le Fort; D012189:Retrospective Studies; D016896:Treatment Outcome
keywords: Le Fort I; maxillary osteotomy; orthognathic surgery; radiographic reference points; surgical wafers