| ObjectiveMeniere’s disease is a common clinical inner ear disease mainly manifested by vertigo,tinnitus and fluctuating hearing loss.However,due to insufficient understanding of the disease,there has been no clear conclusion on the etiology and pathological mechanism of the disease.By analyzing the frequency characteristics of horizontal semicircular canal injury in patients with Meniere’s disease,this study explored the characteristics of the disease injury and clarified the structural basis of the frequency characteristics of the injury through the ultrastructural analysis of the ampullary crest,so as to provide help for the etiological and pathological analysis of Meniere’s disease.MethodsThe subjects were 72 patients with Meniere’s disease admitted to Vertigo disease department of our hospital from March,2019 to November,2019.Among them,27 were males and 45 were females,ranging in age from 13 to 74 years,and the disease course ranged from 4 months to 32 years.Caloric test,sinusoidal harmonic acceleration test（SHA）,video-head impulse test（v-HIT）,Gadolinium-enhanced inner-ear 3D-FLAIR MRI after intravenous injection and pure tone audiometry were conducted in 72 patients.The functional characteristics of the horizontal semicircular canal crista ampullaris in the patients with Meniere’s disease and its relationship with the degree of endolymphatic hydrops,clinical stage and duration.Light microscopy and transmission electron microscopy were used to observe the horizontal semicircular canal crista ampullaris of 6 patients with refractory Meniere’s disease who were performed Labyrinthectomy.And the number of type Ⅰ and type Ⅱ vestibular hair cells,the common pathophysiological changes of horizontal semicircular canal crista ampullaris were investigated in these patients.Statistical analysis was performed using SPSS 19.0.ResultsWith the increase of detection frequency,the abnormal rate decreased gradually.The abnormal rate of caloric test was 69.4%（50/72）,SHA 51.4%（37/72）,V-HIT 36.1%（26/72）,comparation of the positive rate among the three tests showed statistically significant differences（P<0.05）.Neither caloric test nor SHA had correlation with the degree of hydrops（P>0.05）,but v-HIT had correlation with the degree of hydrops（r=0.434,P<0.01）.Caloric test had no correlation with clinical staging（P>0.05）,SHA and V-HIT had correlation with clinical staging（r=0.338、0.462,P<0.01）.Caloric test,SHA,v-HIT were not associated with course of disease（P>0.05）.The horizontal semicircular canal crista ampullaris showed monolayer epithelialization,type Ⅱ hair cells decreased significantly compared with type Ⅰ.Hair cells were frequently observed perinuclear vacuolization,cytoplasmic vacuoles,mitochondrial electron density increase,loss of stereocilia,pathological myelinated nerve fibers and capillaries are often seen in the sensory subepithelial stroma.ConclusionsThe horizontal semicircular canal damage in the patients with Meniere’s disease has a frequency characteristic,mainly occurred in low frequency area.With progress of the disease,the damage of high frequency area appears gradually,and it is related to the degree of endolymphatic hydrops and the degree of hearing loss.Hair cell injury were observed,the frequency characteristics may be more associated with the disorder of type Ⅱ hair cells.MeaningIn view of the frequency characteristics of semicircular canal injury at the level of Meniere’s disease and its correlation with the hearing level and the degree of hydrocephalus,the auxiliary diagnosis can be made according to the frequency characteristics of vestibular examination at different degrees of hearing and hydrocephalus of endolymphs while taking clinical symptoms as the main diagnostic basis.The ultrastructural analysis of ampullary crest in Meniere’s disease can be helpful to the basic pathological study of vestibular injury in Meniere’s disease,provide evidence support for the cause analysis of vestibular frequency characteristics of Meniere’s disease,and provide help for the study of the etiology and pathological mechanism of Meniere’s disease. |
