| ObjectiveMost middle ear diseases are related to the ventilation disorder of temporal bone.If the ventilation disorder of temporal bone is not corrected,the therapeutic effect is often unsatisfactory.There are many factors that affect the ventilation of temporal bone.Besides the function of eustachian tube,the cushioning effect of mastoid process and the gas exchange effect of middle ear mucosa can affect the ventilation of temporal bone.However,the ventilation experiment of temporal bone based on human body is difficult to carry out directly,and there is a lack of research on ventilation system taking temporal bone as a whole.The purpose of this study is to take the temporal bone as a whole,establish a numerical simulation model of the ventilation and drainage system of the temporal bone including rock bone,and increase the understanding of the pathogenic mechanism of the diseases related to ventilation disturbance of the temporal bone,so as to predict the curative effect of specific surgery by means of preoperative modeling.MethodsThree normal subjects were included in this study.the eustachian tube function was evaluated by physical examination,tympanogram,eustachian tubomanometry(TMM)and the eustachian tube dysfunction questionnaire(ETDQ-7),and the temporal bone CT data were collected.Based on Mimics 19.0 and Geomagic Wrap 2017,a three-dimensional geometric model of temporal bone air-containing system including eustachian tube bone,tympanum,tympanic membrane,mastoid,petrous apex and part of external auditory canal was established.The pressure change curve of nasopharynx in TMM was used as the pressure inlet boundary condition of the whole temporal bone ventilation system.XFlow 2017x and Abaqus CAE 2018 were used to carry out fluid-structure coupling numerical simulation,and the changes of pressure and flow velocity of external auditory canal,attic,tympanic antrum,petrous apex and mastoid tip in temporal bone air-containing system with time were measured,and the simulated external auditory canal pressure changes were compared with the actual external auditory canal pressure changes measured in TMM.ResultsThe pressure changes in temporal bone ventilation and drainage system can be divided into three stages:pressure rising,pressure maintaining and pressure falling.The simulated peak value of external auditory canal pressure is 320.00±92.93Pa,the actual peak value of external auditory canal pressure is 266.00±126.09Pa,the simulated peak time of external auditory canal pressure is 0.46±0.14s,and the actual peak time of external auditory canal pressure is 0.45±0.26s;in the simulated model,the average peak pressure of the attic is 4648.58±21.53Pa,and the average peak pressure time of the attic is 0.46±0.15s,and the peak velocity in the ascending stage of the attic is 2.86±1.43m/s,and the average peak pressure of the tympanic antrum is 4648.59±21.47Pa,and the average peak pressure time of the tympanic antrum is 0.46±0.15s,and the peak velocity in the ascending stage of the tympanic antrum is 3.47±3.58m/s,and the average peak pressure of the air cells of the petrous apex is 4650.98±17.41Pa,and the mean pressure peak time of the air cells of the petrous apex is 0.45±0.15s,and the peak velocity in ascending stage of the air cells of the petrous apex is 0.064±0.072m/s,and the mean peak pressure of the air cells of the mastoid tip is 4648.67±21.25Pa,and the mean peak pressure time of the air cells of the mastoid tip is 0.45±0.15s,and the peak velocity in ascending stage of the air cells of the mastoid tip is 0.17±0.18m/s.ConclusionThe external auditory canal pressure curve measured by the simulation model established in this study has the same trend as the actual one,but there are great individual differences.The pressure peaks and peak time of the attic,tympanic antrum,petrous apex and mastoid tip are basically the same,but the peak velocity in different parts of the pressure rise stage decreases with the increase of the length of the ventilation path. |
PDF Full Text Request