The Relationship Between The Cochlear Nerve Canal Stenosis And The Cochlear Nerve

Objetive:The aim of this study is to explore the relationship between cochlear nerve canal (CNC) stenosis and cochlear nerve (CN) by using multi-slice CT and magnetic resonance imaging(MRI) in children with sensorineural hearing loss.Methods:During a period of16months,51children (102ears) with unilateral or bilateral sensorineural hearing loss (SNHL) underwent both HRCT and MRI imaging of temporal bone. The51patients is consisted of33males and18females with a mean age of4years (range from9month to10years).45patients with bilateral sensorineural hearing loss,6patients with unilateral sensorineural hearing loss.41patients (82ears) with normal inner acoustic canal (IAC) and cochlear existence were choosed for this study, For all of these, the CNC were measured and divided into three groups according to the diameter of CNC on HRCT, a:>1.8mm, b:1.8mm～1.5mm, c:<1.5mm,at the same time, the presence of CN hypoplasia or aplasia were evaluated by MRI images; First, according to the presence of inner ear malformation,41(76ears) patients were divided into normal and abnormal groups. To explore whether a correlation between CN and inner ear malformation exists between the two groups in certain CNC, If there is a difference, the relation between the CNC stenosis and CN were explored respectively, If not,to study the relation between CNC stenosis and CN for the41patients in all. Results1.among41patients,7patients (14ears)with inner ear malformation were included in abnormal group;6ears with CNC>0.18mm had normal CN,2ears with CNC between0.18mm and0.15mm had normal CN, among6ears with CN <0.15mm,2ears had normal CN.34patients(62ears)with normal inner ear included in the normal group;41ears with normal CN among43ears(CNC>0.18mm) were seen on MRI, among11ears with CNC diameter between0.18mm and0.15mm, of these,9ears had normal CN, the remaining8ears (CNC<0.15mm) all had hypogenetic cochlear nerves. There were no significant difference between the two groups in certain CNC.2.For the41patients (76ears),2ears among49ears(CNC>0.18mm) had CN hypoplasia and aplasia, among13ears with CNC diameter between0.18mm and0.15mm, of these,2ears had CN hypoplasia and aplasia,12ears of the remaining14ears (CNC<0.15mm) had hypogenetic cochlear nerves, It showed moderate correlation between the CNC and CN(r=0.641); The ratio of CN hypoplasia or aplasia were4.1%、15.4%、85.7%respectively.Conclusion1.In certain CNC, there was no significant correlation between the CN and inner ear malformation with normal cochlear.2.Children with CNC stenosis had a high incidence of CN hypoplasia, width of CNC measurement<0.15mm highly supported the existence of CN hypoplasia.3.Normal CN were seen in children with CNC stenosis, Therefore, It is indispensable to receive HRCT、MRI imaging before cochlear implantation(CI).Significancecochlear nerves deficiency (CND) is the rare cause of sensorineural hearing loss which can bring with serious consequence, at present, the therapeutic effect of cochlear nerves deficiency is uncertain. Someone points that CND is the contraindication for cochlear implants(CI). theses patients can choose auditory brainstem implants(ABI), however, this treatment hasn’t been mature. Therefore, The preferred treatment strategy for the majority of deafness is the cochlear implants. To explore the relationship between cochlear nerve canal (CNC) stenosis and cochlear nerve (CN) is meaningful for the diagnosis of CND, which provides a basis fo the the treatment.