The Establishment Of Three Dimensional Numerical Model Of Normal Chinese Inner Ear Structure And Numerical Analysis Of Fluid Structure Interaction

Objective: Through establishjing the three-dimensional numerical model of n ormal chinese people’s inner ear structure,analyze numerical simulation about th e inner Lymph’s Fluid structure interaction under the stimulation,calculating the normal people’s inner Lymph response such as displacement,velocity,pressure under the stimulation.By changing the model,we can numerical simulate the new model,which is LVAS(large vestibular aqueduct syndrome),by use FSI m ethod under the same stimulation.Analyse the differents of the results between the normal and LVAS,and furtherly analysis abnormal response in LVAS,prov iding new ideas and methods for researching LVAS’s pathogenesis and LVAS’s prevention and treatment.Methods: Experimental materials come from a living without disease’s cadav er’s temporal bone specimens(including inner ear),by Micro-CT scanning to ob tain CT image which thickness is 55μm,Through 3D reconstruction software Mimics 17 to establish the model.Then by changing the diameter of Vestibular aqueduct to establish the other two different diameter LVAS’s 3D inner model.Then using Geomagic Studio 12 software to construct patches on the model,fi nally using mechanical analysis software ADINA8.8 to analyse inner Lymph Flu id structure interaction,calculating the biomechanical response of the normal a nd patients with LVAS.Results: 1(1)Normal people impacted by external stimulation,causing cha nges of cerebrospinal fluid pressure(maximum pressure were 10 KPa,100KPa,150 KPa,200KPa,250 KPa,300KPa),leading to secondary tympanic membrane m aximum displacement and pressure trend of change broadly consistent with exter nal load.the maximum displacement in(5.6±0.4)E-3s,the maximum displacem ents’ peak value were 1.64E-02 mm,1.76E-01 mm,2.82E-01 mm,4.13E-01 mm,6.00E-01 mm,9.06E-01 mm.the maximum pressure in(5.6±0.4)E-3s,maximum pr essures’ peak value were 9.87E-03 MPa,9.89E-02 MPa,1.49E-01 MPa,1.99E-01 MPa,2.49E-01 MPa,2.87E-01 MPa.(2)normal in outside stimulation(maximum pressure were 10 K Pa,100 KPa,150KPa,200 KPa,250KPa,300KPa)lead to cerebrospinal fluid pre ssure changes prodece the first peak speed of cochlear window in(3.7±0.7)E-3s,the peak velocity value were 5.04 E +00mm/s,5.40E+01mm /s,8.56 E +01m m/s 1.23 E +02mm/s,1.74E+02mm/s,2.49E+02mm /s.in(7.35±0.15)E-3s produ ce the second peak speed value,were 4.85 E +00mm/s 5.29E+01 mm/s,8.48E+01mm/s,1.27E+02 mm/s,2.17E+02mm/s,4.44E+02mm/s.2(1)Thickened people impacted by external stimulation,causing c hanges of cerebrospinal fluid pressure(maximum pressure were 10 KPa,100KPa,150 KPa,200KPa,250 KPa,300KPa),leading to secondary tympanic membrane maximum displacement and pressure trend of change broadly consistent with ext ernal load.the maximum displacement in(5.55±0.35)E-3s,the maximum displa cements’ peak value were 1.69E-02 mm,1.79E-01 mm,2.85E-01 mm,4.15E-01 mm,6.04E-01 mm,9.88E-01 mm.the maximum pressure in(5.65±0.45)E-3s,maximu m pressures’ peak value were 9.85E-03 MPa,9.87E-02 MPa,1.48E-01 MPa,1.98E-01 MPa,2.49E-01 MPa,2.90E-01 MPa.(2)Thickened people in outside stimulation(maximum pressure were 10 KPa,100KPa,150 KPa,200KPa,250 KPa,300KPa)lead to cerebrospinal fluid pressure changes prodece the first peak speed of cochlear window in(3.80± 0.80)E-3s,the peak velocity value were 5.17 E +00mm /s,5.48E+ 01 mm /s,8.73 E +01 mm /s 1.26 E +02 mm /s,1.81 E +02mm /s,2.84 E +02mm /s.in(6.95 ± 0.55)E-3s produce the second peak speed value,were 4.96 E +00 mm /s 5.32 E +01 mm /s,8.56E+01 mm/s,1.27E+02 mm / s,2.10E+02 mm / s,5.99E+02 mm / s.3(1)The most thickened people impacted by external stimulation,causin g changes of cerebrospinal fluid pressure(maximum pressure were 10 KPa,100KPa,150 KPa,200KPa,250 KPa,300KPa),leading to secondary tympanic memb rane maximum displacement and pressure trend of change broadly consistent wit h external load.the maximum displacement in(5.35±0.05)E-3s,the maximum displacements’ peak value were 1.89E-02 mm,1.97E-01 mm,3.09E-01 mm,4.42E-01 mm,6.22E-01 mm,1.06E+00mm.the maximum pressure in(5.35±0.15)E-3s,maximum pressures’ peak value were 9.80E-03 MPa,9.80E-02 MPa,1.47E-01 M Pa,1.96E-01 MPa,2.45E-01 MPa,2.97E-01 MPa.(2)The most thickened in outside stimulation(maximum pressure wer e 10 KPa,100KPa,150 KPa,200KPa,250 KPa,300KPa)lead to cerebrospinal flu id pressure changes prodece the first peak speed of cochlear window in(3.80±0.80)E-3s,the peak velocity value were 5.17 E +00mm /s,5.48E+ 01 mm /s,8.73 E +01 mm /s 1.26 E +02 mm /s,1.81 E +02mm /s,2.84 E +02mm /s.in(6.95±0.55)E-3s produce the second peak speed value,were 4.96 E +00 mm /s 5.32E+01 mm /s,8.56E+01 mm/s,1.27E+02 mm / s,2.10E+02 mm / s,5.99E+02mm / s.4.Under the highest pressure 300 KPa stimulation,normal,thickened,most thickeneds’ basement membranes’ pressure were 280.2KPa,287.5KPa,299.8KP a.Normal,thickened,most thickeneds vestibular aqueduct limit 19.8KPa,12.5K Pa,0.2KPa into inner.And,in 300 KPa,normal vestibular aqueduct limiting effect is1.6 times of the thickened,normal vestibular aqueduct limiting effect is 99 tim es of the most thickened model.Conclusion: 1 Establish the normal people,LVAS’s three-dimensional nu merical model of inner ear structure.The numerical model including the cochlea,vestibule,semicircular canal,vestibular aqueduct and endolymphatic sac.Provid ing a platform for further numerical simulate of the inner ear system.2 Normal inner ear vestibular aqueduct have a certain degree of limiting effect to cerebrospinal fluid pressure fluctuations into inner ear,includi ng limiting displacement,pressure,veolcity.The vestibular aqueduct is finer,mor e restrictive effect.With the aqueduct was increasing.The limiting effect decrea ses gradually.3 Normal vestibular aqueduct restriction to external stimulation int o the inner ear is gradually increased with the increased of the external stimulat ion.Patients with LVAS’s inner lymph changes more under the external stimulus,this is according with the LVAS’s mechanism theory of leaing to deaf that inn er lymph pressure change more can damage to the hair cells of the inner ear.4 The experimental results are agree with the literature data,clinical mani festations and medical patients,therefore this experimental technique is feasible,calculation results is reliable.Analysis of LVAS relevance of causing-organic change-correlation function abnormality-clinical manifestation from biomecha nical aspect,providing a theoretical basis and feasibility of biomechanics for cli nical prevention and treatment of LVAS in the future.