Aural atresia is the absence of an external ear canal. Patients with aural atresia usually have a malformation of the external and middle ear, but the inner ear and auditory nerve are frequently normal.
A narrowed ear canal is sometimes referred to as a stenotic canal, or canal stenosis. In congenital aural atresia, the external auditory canal and structures in the middle ear fail to develop completely. Development of the ear canal and middle ear may be arrested at any point in the process. There may be varying degrees of severity of this malformation. In the severe form, no identifiable ear canal exists, and the middle ear and ossicles or ear bones may be absent or show significant underdevelopment.
Aural atresia most commonly effects just one ear (unilateral aural atresia), but can occur in both ears (bilateral aural atresia).
Congenital aural atresia is commonly accompanied by microtia ("small ear"), or incomplete development of the auricle, which is also a surgical reconstructive challenge.
Atresia is most frequently isolated, but can be a symptom of a larger syndrome, such as Treacher Collins, Goldenhar, Crouzon's, Alpert's, Pfeiffer, Klippel-Feil, BOR (Branchio-Oto-Renal) also known as Melnick-Fraser, 18-q chromosome, as well as Hemifacial Microsomia.
Surgical options
There are two separate issues regarding the ear:
- Auricular reconstruction to restore the visual appearance and form of the outer ear
- Repair of atresia or application of a Bone Conduction Hearing Solution (BAHA) to restore hearing.
The surgery to create a normal sized ear canal from either a stenotic canal or complete aural atresia is known as an "atresia repair" and is sometimes also referred to as a canalplasty. The otologist must consider the hearing needs of the child, especially with regard to bilateral atresia, and must determine not only the appropriate treatment, but also the timing of that treatment. The otologist must work closely with the facial plastic surgeon to determine the optimal time for atresia repair.