title: Evaluation of pharyngeal airway space changes after bimaxillary orthognathic surgery with a 3-dimensional simulation and modeling program.
abstract: BACKGROUND
  The aims of this study were to use 3-dimensional simulation and modeling programs to evaluate the effects of bimaxillary orthognathic surgical correction of Class III malocclusions on pharyngeal airway space volume, and to compare them with the changes in obstructive sleep apnea measurements from polysomnography.
  
  
  METHODS
  Twenty-five male patients (mean age, 21.6 years) with mandibular prognathism were treated with bilateral sagittal split osteotomy and LeFort I advancement. Polysomnography and computed tomography were performed before surgery and 1.4 ± 0.2 years after surgery. All computed tomography data were transferred to a computer, and the pharyngeal airway space was segmented using SimPlant OMS (Materialise Medical, Leuven, Belgium) programs. The pretreatment and posttreatment pharyngeal airway space determinants in volumetric, linear distance, and cross-sectional measurements, and polysomnography changes were compared with the paired samples t test. Pearson correlation was used to analyze the association between the computed tomography and polysomnography measurements.
  
  
  RESULTS
  The results indicated that setback procedures produce anteroposterior narrowing of the pharyngeal airway space at the oropharyngeal and hypopharyngeal levels and the middle and inferior pharyngeal volumes (P <0.05). In contrast, advancement of the maxilla causes widening of the airway in the nasopharyngeal and retropalatal dimensions and increases the superior pharyngeal volume (P <0.05). Distinctively, bimaxillary orthognathic surgery induces significant increases in the total airway volume and the transverse dimensions of all airway areas (P <0.05). Significant correlations were found between the measurements on the computed tomography scans and crucial polysomnography parameters.
  
  
  CONCLUSIONS
  Bimaxillary orthognathic surgery for correction of Class III malocclusion caused an increase of the total airway volume and improvement of polysomnography parameters. A proposed treatment plan can be modified according to the risk of potential airway compromise or even to improve it with 3-dimensional imaging techniques and polysomnography.
authors.affiliation: Associate professor, Department of Orthodontics, Dental Sciences Center, Gulhane Military Medical Academy, Etlik, Ankara, Turkey. Electronic address: silagokce@yahoo.com.
authors.forename: Sila Mermut
authors.initials: SM
authors.lastname: Gokce
authors.affiliation: Associate professor, Department of Orthodontics, Dental Sciences Center, Gulhane Military Medical Academy, Etlik, Ankara, Turkey.
authors.forename: Serkan
authors.initials: S
authors.lastname: Gorgulu
authors.affiliation: Associate professor, Medical Design and Manufacturing Center, Gulhane Military Medical Academy, Etlik, Ankara, Turkey.
authors.forename: Hasan Suat
authors.initials: HS
authors.lastname: Gokce
authors.affiliation: Professor and chairman of Dental Sciences Center, Department of Orthodontics, Gulhane Military Medical Academy, Etlik, Ankara, Turkey.
authors.forename: Ali Osman
authors.initials: AO
authors.lastname: Bengi
authors.affiliation: Associate professor, Department of Orthodontics, Dental Sciences Center, Gulhane Military Medical Academy, Etlik, Ankara, Turkey.
authors.forename: Umit
authors.initials: U
authors.lastname: Karacayli
authors.affiliation: Associate professor, Department of Radiology, Gulhane Military Medical Academy, Etlik, Ankara, Turkey.
authors.forename: Fatih
authors.initials: F
authors.lastname: Ors
mesh_terms: D000328:Adult; D059925:Anatomic Landmarks / Q000473:pathology; D019412:Anatomy, Cross-Sectional; D002508:Cephalometry / Q000379:methods; D003198:Computer Simulation; D005500:Follow-Up Studies; D006801:Humans; D007013:Hypopharynx / Q000473:pathology; D007091:Image Processing, Computer-Assisted / Q000379:methods; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008297:Male; D008313:Malocclusion, Angle Class III / Q000601:surgery; D008953:Models, Anatomic; D009305:Nasopharynx / Q000473:pathology; D009960:Oropharynx / Q000473:pathology; D056948:Orthognathic Surgical Procedures / Q000379:methods*; D019340:Osteotomy, Le Fort / Q000379:methods; D059229:Osteotomy, Sagittal Split Ramus / Q000379:methods; D010159:Palate / Q000473:pathology; D010347:Patient Care Planning; D010614:Pharynx / Q000473:pathology*; D017286:Polysomnography / Q000379:methods; D011378:Prognathism / Q000601:surgery; D020181:Sleep Apnea, Obstructive / Q000628:therapy; D014057:Tomography, X-Ray Computed / Q000379:methods; D055815:Young Adult