Congenital malformations of the inner ear: A classification based on embryogenesis

TLDR

About 20 % of patients with congenital sensorineural hearing loss show inner‑ear radiographic abnormalities, yet many distinct patterns are currently grouped under the umbrella term Mondini’s dysplasia. The authors propose a classification system that links each deformity to a specific arrest in inner‑ear organogenesis. They reviewed 63 patients with 98 malformed ears and identified several distinct anatomic patterns based on radiographic appearance. They contend that grouping diverse entities as Mondini’s dysplasia is unwarranted and demonstrate a striking correspondence between the observed morphologies and stages of embryonic inner‑ear development.

Abstract

Approximately 20% of patients with congenital sensorineural hearing loss have radiographic abnormalities of the inner ear. A broad spectrum of anomalous patterns have been described, most of which have been lumped together under the term "Mondini's dysplasia." We feel that this grouping of many dissimilar entities under a single umbrella term is unwarranted. Based on a review of 63 patients with 98 congenitally malformed ears, we have been able to recognize a number of distinct anatomic patterns from their radiographic appearance. A remarkable similarity between these morphologies and the appearance of the inner ear at various stages of embryogenesis was found. This led us to propose a classification system based upon the theory that these deformities result from an arrest of development during varying stages of inner ear organogenesis.