microtia

Microtia refers to a small pinna of the ear, when is it completely absent it is termed anotia.

Epidemiology

The estimated incidence at around 1:9000 live births. It is more common in males and there is a recognized right sided predilection.

Pathology

Associations

Microtia can be associated with a wide spectrum of inner and middle ear anomalies . Isolated microtia is relatively uncommon. The most frequent associations include:

• ossicular dysplasia
• external auditory canal stenosis
• external auditory canal atresia

Wider organ associations include:

• renal anomalies
  • cross-fused ectopia
  • renal agenesis

Syndromic associations include:

• Down syndrome
• Goldenhar syndrome
• Jacobsen syndrome
• Nager syndrome
• Treacher-Collins syndrome

Classification

It is classified into four grades based on increasing severity:

• grade I: slightly small ear with identifiable structures; external auditory canal small but present
• grade II: partial or hemiear with a occluded or stenotic external ear canal producing a conductive hearing loss 
• grade III: absence of the external ear with a small peanut like vestige structure and an absence of the external ear canal and eardrum
• grade IV: complete absence (anotia)

Siehe auch:

• Down-Syndrom
• einseitige Nierenagenesie
• Franceschetti-Zwahlen-Syndrom
• Goldenhar-Gorlin-Syndrom
• Gehörgangsatresie
• Jacobsen syndrome
• OFM Nager-Syndrom
• cross-fused ectopia

und weiter:

• Thalidomid-Embryopathie
• Walker-Warburg-Syndrom
• acrofacial dyostosis
• abnormal middle and external ears