Evaluation of embryological sequences of ear anomalies and its radiological relevance

Abstract

Aim: To correlate the sequence of embryological development of ear with radiological imaging. Materials and Methods: The study enrolled 23 patients of age group 11 months to 27 years with malformed external ear/microtia and hearing loss. The children with postoperative changes, acute hearing loss (such as infection, trauma) were excluded from the study. We used high-resolution computed tomography, with axial and coronal sections to examine the temporal bones of patients. Results: Of the 23 cases, 12 cases had external ear anomaly and 11 cases had cochlear anomaly. In patients with the external ear anomaly, seven cases had associated middle ear malformations, one patient had associated middle and inner ear anomaly, one had anomalous course of facial nerve, and three cases had isolated external ear anomalies. In patients with inner ear anomalies, one patient had complete labyrinthine aplasia, one had cochlear dysplasia with incomplete cochlear turns, four had common cavity malformations, one had cystic featureless cochlea with dilated and cystic vestibule, two patients had small cochlea with the middle and apical turns coalescing to form a cystic apex, one patient had small rudimentary cochlea, and the other one had dilated vestibule and enlarged endolymphatic duct and sac with cochlear dysmorphism. Conclusion: Most of the children with malformed pinna had external auditory canal atresia with associated middle ear anomalies. Though the inner ear development is independent of external and middle ear development, we insist on the fact that insult during the 1 st month of embryogenesis can result in associated abnormalities involving external, middle, and inner ear. Developmental arrest at various stages of inner ear development results in various types of cochlear anomalies with associated vestibular, semicircular canal abnormalities, and rarely associated with middle and external ear anomalies. Hence, clear knowledge about embryology will help to guide the management.