Computational fluid dynamics of the effect of mandibular counter-clockwise rotation on the airway: a novel treatment strategy for sleep apnea

2022 Fiscal Year Final Research Report

• Project/Area Number: 19K19261
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 57070:Developmental dentistry-related
• Research Institution: Tokyo Medical and Dental University
• Principal Investigator: Kita Soma 東京医科歯科大学, 大学院医歯学総合研究科, 非常勤講師 (40822515)
• Project Period (FY): 2019-04-01 – 2023-03-31
• Keywords: 顎変形症 / 上気道 / 流体力学

Outline of Final Research Achievements

Changes in the upper airway and the resulting alteration in the nasal respiratory function after jawbone repositioning during orthognathic surgery have garnered attention recently. This study aimed to perform a functional evaluation of the effects of surgery involving maxillary repositioning, which may result in a larger airway resistance if the stenosis worsens the respiratory function, using CFD for treatment planning.
The pressure drop in the airway was lower in the postoperative compared to the preoperative.The closer the rate of change in the cross-sectional area of the mass extending pharynx is to 1, the smaller the pressure drop, so ideally the airway should be constant.
Therefore, the analysis of the effects of repositioning on nasal ventilation showed that current surgery is appropriate with respect to functionality, as it does not compromise respiratory function. This study identified airway shapes that are favorable from the perspective of fluid dynamics.

Free Research Field

歯科矯正学

Academic Significance and Societal Importance of the Research Achievements

骨格性下顎後退症に適用される従来の下顎骨前方移動術は術後安定性に不安があり、変形症顎関節症や進行性下顎頭吸収による後戻りに伴う気道狭窄が危惧されてきた。その狭窄は単に形態的変化であるのか、機能的な変調を伴うのか不明で、閉塞性睡眠時無呼吸症誘発の可能性も問題視される。それらに対応した術式として、下顎を離断せず下顎骨を前方移動させるMAC surgeryが考案された。MAC surgeryは上顎骨後上方移動による狭窄が懸念される一方、下顎骨前方移動で咽頭部は拡大するため、通気への影響を計算流体力学で評価する。その結果を元に、気道に影響を与える術式を解明することで、新たな術式の開発も可能となる。