Learning objectives
To describeimaging findings incochlear hypoplasia malformations.
To specify cochlear implantation indications and challenges in each type of cochlear hypoplasia.
Background
Inner ear malformations is a general term describing various types of cochlear anomalies. The latest classification of IEM established by Sennaroglu et al. using computerized tomography (CT) and magnetic resonance imaging (MRI), included eight groups (1). Cochlear hypoplasia (CH) represents a group of malformations where external dimensions are less than those of a normal cochlea with various internal architecture anomalies. They are divided into four different subgroups, according to the cochlear development degree on CT (1).
These different subgroups present large different clinical presentations and...
Findings and procedure details
Imaging characterization of cochlear malformation is based mainly in temporal bone CT. Inner ear structures should be analyzed in the reference axial plan, parallel to the lateral semicircular canal, as well as in multiplanar reconstructions (MPR).
Cochlear measurements,taken at both reference axial plan and coronal reconstruction, are essential to distinguishCH from other types of IEM (4).
Magnetic resonance imaging (MRI) of the inner ear, espaciallyhigh-resolution heavily T2-weighted three-dimensional (3D) sequences on oblique sagittal reconstructions, enable direct visualization of the vestibulo-cochlear nerve bundles. As cochlear nerve...
Conclusion
Classification of the different types of CH seems to be of clinical significance, as according to several studies, the post-operative outcomes are different from CH I to CH IV and performing cochlear measurements is of a high importance in order to recognize cochlear hypoplasia's different subtypes.
Hence, it is mandatory to correctlydiagnoseCH, in order to select cochlear implantations candidates, as this surgery can be a real challenge in these particular cases.
Personal information and conflict of interest
S. Siala; Tunis/TN - nothing to disclose M. Jrad; Tunis/TN - nothing to disclose S. Sbaihi; Tunis/TN - nothing to disclose S. Boukriba; Tunis/TN - nothing to disclose W. Frikha; Tunis/TN - nothing to disclose H. Mizouni; Tunis/TN - nothing to disclose
References
1-Sennaroglu L, Bajin MD. Classification and current management of inner ear malformations. Balk Med J. 2017;34(5):397‑411.
2- Cinar BC, Batuk MO, Tahir E, Sennaroglu G, Sennaroglu L. Audiologic and radiologic findings in cochlear hypoplasia. Auris Nasus Larynx. 2017;44(6):655‑63.
3- Joshi VM, Navlekar SK, Kishore GR, Reddy KJ, Kumar ECV. CT and MR imaging of the inner ear and brain in children with congenital sensorineural hearing loss. Radiographics. 2012;32(3):683‑98.
4- Purcell D, Johnson J, Fischbein N, Lalwani AK. Establishment of normative cochlear and vestibular measurements to...
