title: Change in the Upper Airway of Patients With Obstructive Sleep Apnea Syndrome Using Computational Fluid Dynamics Analysis: Conventional Maxillomandibular Advancement Versus Modified Maxillomandibular Advancement With Anterior Segmental Setback Osteotomy.
abstract: OBJECTIVE
  The aim of the study was to compare the effect of conventional maxillomandibular advancement (MMA) and modified MMA with anterior segmental setback osteotomy (MMA-ASSO) on the airway changes in patients with obstructive sleep apnea syndrome (OSAS) using three-dimensional computational fluid dynamics (3D-CFD) analysis.
  
  
  METHODS
  Two adult male patients with Class I malocclusion, lip protrusion, acute nasolabial angle, and OSAS were treated with conventional MMA (Case 1) and modified MMA-ASSO (Case 2). Individualized 3D airway models were fabricated using computed tomography data obtained 1 month before (T0) and at least 6 months after surgery (T1). A total of 7 cross-sectional areas of the airway were established, starting just above the hard palate (plane 1) with interval of 1 mm caudally. Airflow velocity and negative pressure were investigated using CFD analysis, and polysomnography studies were performed at T0 and T1.
  
  
  RESULTS
  There were improvement of apnea-hypoapnea index and the lowest O2 level (T0 versus T1; 43.2 versus 15.2, 79% versus 90% in Case 1; 61.0 versus 6, 89% versus 92% in Case 2). At plane 2 (retropalatal area) in Cases 1 and 2, there were increase in the smallest cross-sectional areas (57.9% versus 28.4%), decrease in the airflow velocity and increase in the negative pressure at the peak of expiration (49.5% versus 31.7%; 88.4% versus 54.3%), end after expiration (53.2% versus 32.2%; 83.2% versus 47.9%), and peak of inspiration (53.1% versus 29.2%; 75.3% versus 48.2%).
  
  
  CONCLUSIONS
  Modified MMA-ASSO method might be an effective treatment option for OSAS patients with improvement of airway problems and esthetic facial profile.
authors.affiliation: *Department of Oral and Maxillofacial Surgery, School of Dentistry, Seoul National University, Chongno-Gu †Graduate School of Mechanical Engineering, Soongsil University, Dongjak-Gu ‡Department of Orthodontics, School of Dentistry, Dental Research Institute, Seoul National University, Chongno-Gu §Department of Mechanical Engineering, Soongsil University, Dongjak-Gu ||Department of Oral and Maxillofacial Surgery, School of Dentistry, Dental Research Institute, Seoul National University, Chongno-Gu, Seoul, South Korea.
authors.forename: Taeyun
authors.initials: T
authors.lastname: Kim
authors.forename: Hyoung-Ho
authors.initials: HH
authors.lastname: Kim
authors.forename: Sung ok
authors.initials: So
authors.lastname: Hong
authors.forename: Seung-Hak
authors.initials: SH
authors.lastname: Baek
authors.forename: Kyung-Wuk
authors.initials: KW
authors.lastname: Kim
authors.forename: Sang-Ho
authors.initials: SH
authors.lastname: Suh
authors.forename: Jin-Young
authors.initials: JY
authors.lastname: Choi
mesh_terms: D000328:Adult; D019412:Anatomy, Cross-Sectional; D005500:Follow-Up Studies; D063172:Genioplasty / Q000379:methods; D006801:Humans; D057446:Hydrodynamics; D007091:Image Processing, Computer-Assisted / Q000379:methods; D021621:Imaging, Three-Dimensional / Q000379:methods; D001239:Inhalation / Q000502:physiology; D008297:Male; D008311:Malocclusion, Angle Class I / Q000601:surgery; D019186:Mandibular Advancement / Q000379:methods*; D063166:Maxillary Osteotomy / Q000379:methods*; D019340:Osteotomy, Le Fort / Q000379:methods; D059229:Osteotomy, Sagittal Split Ramus / Q000379:methods; D021362:Palate, Hard / Q000033:anatomy & histology; D066230:Patient-Specific Modeling; D010366:Peak Expiratory Flow Rate / Q000502:physiology; D010614:Pharynx / Q000033:anatomy & histology*; D017286:Polysomnography / Q000379:methods; D011312:Pressure; D012123:Pulmonary Ventilation / Q000502:physiology; D020181:Sleep Apnea, Obstructive / Q000601:surgery*; D014057:Tomography, X-Ray Computed / Q000379:methods