Inner ear malformations (classification)
Updates to Article Attributes
Cochlear anomalies are variety of congenital anomalies which, depending on the exact time at which an insult occurs during embryogenesis, may have different manifestations. Terminology is often used imprecisely leading to confusion not only among clinicians but also in the literature.
Classification
A classification first proposed in 1987 by Jackler et al 2 has become widely accepted (with various modification), which divides congenital cochlear anomalies according to the timing of developmental arrest.
Conveniently starting at 3rd week till the end of 7thweek of gestation, an insult during each subsequent week results in a distinct inner ear abnormality:
- complete labyrinthine aplasia or Michel deformity: 3rd week
- cochlear aplasia: 4th week
- common cavity malformation to the cochlea and vestibule: early 5th week
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Typetype I incomplete partition (cystic cochleovestibular anomaly): late 5th week - cochlear hypoplasia: 6th week
- incomplete partition (IP) type II including Mondini dysplasia: 7th week
-<a href="/articles/michel-aplasia">complete labyrinthine aplasia</a> or Michel deformity: 3<sup>rd</sup> week</li>- +<a href="/articles/michel-aplasia">complete labyrinthine aplasia</a> or <a title="Michel deformity" href="/articles/michel-deformity">Michel deformity</a>: 3<sup>rd</sup> week</li>
-<a href="/articles/type-i-incomplete-partition-1">Type I incomplete partition </a>(cystic cochleovestibular anomaly): late 5<sup>th</sup> week</li>- +<a href="/articles/type-i-incomplete-partition-1">type I incomplete partition </a>(cystic cochleovestibular anomaly): late 5<sup>th</sup> week</li>
-<a title="Cochlear hypoplasia" href="/articles/cochlear-hypoplasia">cochlear hypoplasia</a>: 6th week</li>- +<a href="/articles/cochlear-hypoplasia">cochlear hypoplasia</a>: 6th week</li>