ABSTRACT
Background: congenital SNHL may be caused by abnormalities of th-e membranous, or bony labyrinth. Because of
improvements in imaging techniques and appearance of high resolution CT and MRI, anomalies of bony labyrinth can
be diagnosed. MR imaging helps in identification of non-osseous partitioning of the malformed cochlea and
identification of the neural structures contained within the internal auditory canal. The cochlear implantation has
radically changed the outlook for profoundly deaf adults and children. Aim of work: to identify different types of
inner ear anomalies, and to detect the percentage of patients who are amenable to cochlear implantation, and
difficulties that occur during the operation. Patients and methods: This prospective study was carried out on sixty
patients from 2015 till 2017 in ORL Department, Zagazig University. All patients underwent thorough preoperative
evaluation especially by high resolution CT and MRI. These patients were classified according to type of diagnosed
anomaly, and CI operation were done to patients who were amenable for surgery. Results: The results of this study
show congenital inner ear anomalies distribution according to involved part and its percent in relation to total number
120 ears. Cochlear hypoplasia is present in 6 ears 4.5%, common cavity is present in 4 ears 3%, IP1 is present in 4 ears
3%, IP2 is present in 22 ears 16.7%, IP3 is present in 10 ears 7.6%, posterior rotated cochlea is present in 8 ears 6.1%,
dilated vestibule is present in 4 ears 3%, isolated SCC hypoplasia is present in 4 ears 3.03%, SCC hypoplasia with
common cavity is present in 4 ears 3.03%, dysplstic SCC is present in 9 ears 6.8%, dilated IAC is present in 6 ears
4.5%, hypoplastic IAC is present in 24 ears 18.2%, VCN hypoplasia is present in 24 ears 18.2%, isolated EVA is
present in 48 ears 36.4%. In our study all operated cases were done through facial recess approach. Operated cases were
51 out of 66 about 77.3%. Conclusion: CT and MRI are mandatory investigations for any patient prepared for cochlear
implantation. Preoperative diagnosis of inner ear anomalies allows exclusion of anomalies that are considered as
contraindication for CI operation.