title: Computational Fluid Dynamic Study of Nasal Respiratory Function Before and After Bimaxillary Orthognathic Surgery With Bone Trimming at the Inferior Edge of the Pyriform Aperture.
abstract: OBJECTIVE
  This study aimed to evaluate the influence of maxillary impaction orthognathic surgery on nasal respiratory function and the efficacy of bone trimming at the inferior edge of the pyriform aperture.
  
  
  METHODS
  The participants were 10 patients (3 male and 7 female patients) with mandibular prognathism who underwent bimaxillary orthognathic surgery with maxillary impaction. The surgical procedures performed were Le Fort I osteotomy with bone trimming at the inferior edge of the pyriform aperture and bilateral sagittal split osteotomy. Three-dimensional models of the nasal cavity were reconstructed from preoperative and postoperative computed tomography images. Furthermore, we remodeled the nasal valve region based on the postoperative models by adding a 1-mm and 2-mm stenosis to investigate the effects of bone trimming at the inferior edge of the pyriform aperture on the pressure effort. The 3-dimensional models were simulated with computational fluid dynamics, and the results of the pressure effort and the cross-sectional area (CSA) were compared for the anterior, middle, and posterior parts of the nasal cavity. The Wilcoxon signed rank test and Spearman rank correlation coefficients were used for statistical comparisons (P < .05).
  
  
  RESULTS
  In the preoperative and postoperative models, there were considerable correlations between the CSA and the pressure effort in each part of the nasal cavity. The postoperative pressure effort showed a tendency to decrease and the CSA showed a tendency to increase in each part of the nasal cavity. In four 2-mm stenosis models, the pressure effort in the anterior nasal cavity was larger than the preoperative pressure effort and the CSA of the anterior nasal cavity was smaller than the preoperative CSA.
  
  
  CONCLUSIONS
  Bone trimming at the inferior edge of the pyriform aperture appears to be useful for avoiding nasal respiratory complications with maxillary impaction.
authors.affiliation: Postgraduate Student, Department of Orthodontic Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Yushima, Bunkyo-ku, Tokyo, Japan. Electronic address: s.kita.orts@gmail.com.
authors.forename: Soma
authors.initials: S
authors.lastname: Kita
authors.affiliation: Professor, Institute of Industrial Science, The University of Tokyo, Komaba, Meguro-ku, Tokyo, Japan.
authors.forename: Marie
authors.initials: M
authors.lastname: Oshima
authors.affiliation: Assistant Professor, Department of Orthodontic Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Yushima, Bunkyo-ku, Tokyo, Japan.
authors.forename: Kazuo
authors.initials: K
authors.lastname: Shimazaki
authors.affiliation: Assistant Professor, Department of Oral and Maxillofacial Surgery, Yokohama City University Graduate School of Medicine, Fukuura, Kanazawa-ku, Yokohama, Kanagawa, Japan.
authors.forename: Toshinori
authors.initials: T
authors.lastname: Iwai
authors.affiliation: Professor, Department of Oral and Maxillofacial Surgery, Yokohama City University Medical Center, Urafunecho, Minami-ku, Yokohama, Kanagawa, Japan.
authors.forename: Susumu
authors.initials: S
authors.lastname: Omura
authors.affiliation: Professor, Department of Orthodontic Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Yushima, Bunkyo-ku, Tokyo, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Ono
mesh_terms: D003198:Computer Simulation; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D057446:Hydrodynamics; D021621:Imaging, Three-Dimensional; D008297:Male; D008313:Malocclusion, Angle Class III / Q000503:physiopathology / Q000601:surgery*; D008953:Models, Anatomic; D015508:Nasal Obstruction / Q000175:diagnosis / Q000209:etiology / Q000503:physiopathology / Q000517:prevention & control*; D009666:Nose / Q000000981:diagnostic imaging / Q000503:physiopathology*; D019340:Osteotomy, Le Fort / Q000379:methods*; D059229:Osteotomy, Sagittal Split Ramus; D011183:Postoperative Complications / Q000175:diagnosis / Q000503:physiopathology / Q000517:prevention & control*; D011312:Pressure; D056144:Pyriform Sinus; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome