title: Cephalometric and three-dimensional assessment of the posterior airway space and imaging software reliability analysis before and after orthognathic surgery.
abstract: OBJECTIVE
  This study aimed to compare the reliability of three different imaging software programs for measuring the PAS and concurrently to investigate the morphological changes in oropharyngeal structures in mandibular prognathic patients before and after orthognathic surgery by using 2D and 3D analyzing technique.
  
  
  METHODS
  The study consists of 11 randomly chosen patients (8 females and 3 males) who underwent maxillomandibular treatment for correction of Class III anteroposterior mandibular prognathism at the University Hospital in Zurich. A set of standardized LCR and CBCT-scans were obtained from each subject preoperatively (T0), 3 months after surgery (T1) and 3 months to 2 years postoperatively (T2). Morphological changes in the posterior airway space (PAS) were evaluated longitudinally by two different observers with three different imaging software programs (OsiriX(®) 64-bit, Switzerland; Mimics(®), Belgium; BrainLab(®), Germany) and manually by analyzing cephalometric X-rays.
  
  
  RESULTS
  A significant increase in the upper airway dimensions before and after surgery occurred in all measured cases. All other cephalometric distances showed no statistically significant alterations. Measuring the volume of the PAS showed no significant changes in all cases. All three software programs showed similar outputs in both cephalometric analysis and 3D measuring technique.
  
  
  CONCLUSIONS
  A 3D design of the posterior airway seems to be far more reliable and precise phrasing of a statement of postoperative gradients than conventional radiography and is additionally higher compared to the corresponding manual method. In case of Class III mandibular prognathism treatment with bilateral split osteotomy of the mandible and simultaneous maxillary advancement, the negative effects of PAS volume decrease may be reduced and might prevent a developing OSAS.
authors.affiliation: Department of Cranio-Maxillofacial and Oral Surgery, University Hospital Zurich, Switzerland. Electronic address: s0471919@me.com.
authors.forename: John Patrik Matthias
authors.initials: JP
authors.lastname: Burkhard
authors.affiliation: Department of Cranio-Maxillofacial and Oral Surgery, University Hospital Zurich, Switzerland.
authors.forename: Ariella Denise
authors.initials: AD
authors.lastname: Dietrich
authors.affiliation: Department of Cranio-Maxillofacial and Oral Surgery, University Hospital Zurich, Switzerland.
authors.forename: Christine
authors.initials: C
authors.lastname: Jacobsen
authors.affiliation: Biostatistics Unit, Institute of Social and Preventive Medicine, University of Zurich, Switzerland.
authors.forename: Malgorzota
authors.initials: M
authors.lastname: Roos
authors.affiliation: Department of Cranio-Maxillofacial and Oral Surgery, University Hospital Zurich, Switzerland.
authors.forename: Heinz-Theo
authors.initials: HT
authors.lastname: Lübbers
authors.affiliation: Department of Cranio-Maxillofacial and Oral Surgery, University Hospital Zurich, Switzerland.
authors.forename: Joachim Anton
authors.initials: JA
authors.lastname: Obwegeser
mesh_terms: D000328:Adult; D059925:Anatomic Landmarks / Q000000981:diagnostic imaging; D002508:Cephalometry / Q000379:methods* / Q000706:statistics & numerical data; D054893:Cone-Beam Computed Tomography / Q000379:methods* / Q000706:statistics & numerical data; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D006928:Hyoid Bone / Q000000981:diagnostic imaging; D007091:Image Processing, Computer-Assisted / Q000706:statistics & numerical data*; D021621:Imaging, Three-Dimensional / Q000379:methods* / Q000706:statistics & numerical data; D008297:Male; D008313:Malocclusion, Angle Class III / Q000000981:diagnostic imaging / Q000601:surgery; D009295:Nasal Bone / Q000000981:diagnostic imaging; D056948:Orthognathic Surgical Procedures / Q000379:methods*; D019340:Osteotomy, Le Fort / Q000379:methods; D059229:Osteotomy, Sagittal Split Ramus / Q000379:methods; D010614:Pharynx / Q000000981:diagnostic imaging*; D011378:Prognathism / Q000000981:diagnostic imaging / Q000601:surgery; D011897:Random Allocation; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012658:Sella Turcica / Q000000981:diagnostic imaging; D019291:Skull Base / Q000000981:diagnostic imaging; D012984:Software / Q000706:statistics & numerical data*; D055815:Young Adult
keywords: CBCT; Cephalometry; Imaging software; Orthognathic surgery; Posterior airway