Microtia is a congenital malformation of the external and middle ear. The ear may appear as though there is a disorganized remnant of cartilage, or it may have a soft tissue lobule. There are various degrees of the deformity.
Anotia, Congenital Ear Deformity, Aural Atresia
Causes, incidence and risk factors
The exact etiology of microtia is not completely understood, but it is believed that hereditary factors as well as in utero vascular accidents are responsible. Microtia is often seen with other craniofacial deformities. Commonly, microtia is found in patients with hemifacial microsomia, Treacher Collins syndrome, facial asymmetry, epibulbar dermoids, malocclusion, facial nerve weakness and macrostomia.
There are four categories of microtia:
- Grade I: slightly small ear with identifiable structures with a present external ear canal.
- Grade II: partial or hemi-ear with a closed off or stenotic external ear canal producing. There is a conductive hearing loss.
- Grade III: absence of the external ear with a small vestigial ear structure. There is no external ear canal or inner eardrum.
- Grade IV: Total absence of the ear. Also known as Anotia.
Signs and symptoms
Patients with microtia will have a partial ear deformity or complete lack of an ear, with varying degrees of hearing loss.
Patients are given a hearing test first. They may be candidates for a Bone Anchored Hearing Aid (BAHA). Otherwise, they may benefit from inner ear canal reconstruction.
A CT scan will be performed to evaluate the middle ear anatomy.
Depending on a patient’s wishes, he/she may be a candidate for external ear reconstruction using rib cartilage or fabrication of a prosthesis to match the other ear.