Restudy of malformations of the internal auditory meatus, cochlear nerve canal and cochlear nerve

Abstract

The present study aims to restudy the correlation between the internal auditory meatus (IAM), the cochlear nerve canal (CNC), the cochlear nerve (CN) and inner ear malformations. In this retrospective study design, the abnormal diameter of the IAM, CNC and CN in patients with any kind of inner ear malformations was evaluated using multi-slice spiral computed tomography (MSCT) (37 patients) and magnetic resonance imaging (MRI) (18 patients). Of 37 MSCT-diagnosed patients, 2 had IAM atresia, 11 IAM stenosis, 22 enlarged IAM, and 2 normal IAM with an abnormal CN. MRI diagnoses of 18 patients revealed 8 cases of aplastic CN, 6 hypoplastic CN, and 4 normal CN. CNC stenosis was associated with CN hypoplasia (P < 0.001). Patients with absent or stenotic IAM had less CN development than those with normal or enlarged IAM (P = 0.001). We propose a modification of the existing classification systems with a view to distinguishing malformations of the IAM, CNC and CN.

Prevalence of Mutations in GJB2, SLC26A4, and mtDNA in Children with Severe or Profound Sensorineural Hearing Loss in Southwestern China

“…Internal auditory meatus malformation included absence, narrowing (diameter < 2.0 mm or an anteroposterior/ventrodorsal distance < 2.0 mm), or enlargement (diameter > 8 mm). The possibility of cochlear nerve abnormality is considered if the diameter of the cochlear nerve canal < 1.4 mm, as previously reported (Li et al, 2014). EVA was the most common abnormality identified in this study (7.85%, 67/828).…”

The relationship between the dimensions of the internal auditory canal and the anomalies of the vestibulocochlear nerve

“…However, the authors investigated the IAC in individuals aged from 13 to 83 years. Other studies performed on children, like that of Huang et al [10], Lang [12], Li et al [13], and Marques et al [15] classified the normal anteroposterior diameter of the IAC ranging from 3 to 7 mm, from 4.64 to 5 mm, from 2 to 8 mm and stenotic if less than 2 mm, respectively. These variations in considering the normal dimensions could be resulted from the variability in the techniques used in measurements or due to the difference in age groups.…”

Anatomy of the fundus of the internal acoustic meatus — micro-computed tomography study

“…Only cochlear area and the cochlear nerve canal were the subject of intensive morphometric analysis, because it is well visible on the CT scans and can be easily measured. Moreover, the cochlear nerve canal has tremendous clinical significance, because changes of its diameter may be the reason of cochlear nerve deficiency which is believed to be one of the causes of sensorineural hearing loss [8,14].…”