What Is Congenital Aural Atresia?
Aural atresia is a condition in which children are born with an underdeveloped ear canal and middle ear structures. This can result in conductive hearing loss in newborn babies. This condition can also be acquired during their lifetime, which is known as acquired aural atresia, which can occur due to an inflammatory process following a trauma or surgery. The human ear can be divided into three parts: the external ear, the middle ear, and the inner ear. The external ear, which is also known as the outer ear, consists of the auricle and the external auditory canal. The external ear channels the soundwaves to the eardrum and the middle ear.
The condition is caused by failure to integrate the structures during embryonic development, which leads to malformation of the external ear and conductive hearing loss. This condition can occur along with another congenital condition known as microtia. Microtia is another congenital condition in which the pinna does not form correctly.
What Causes Congenital Aural Atresia?
The exact cause of congenital aural atresia is unknown. The condition results from disturbances during the development of the embryo at around the sixth week of gestation. This disturbance will affect the development of the first pharyngeal cleft, which ultimately forms the external auditory canal. This disruption to the development mostly occurs randomly but is seen in association with several syndromes such as Goldenhar (a rare congenital condition characterized by abnormal development of the eye, ear, and spine), Treacher Collins (a rare congenital condition with distinctive abnormalities of the head and the face), and Crouzon syndrome (a genetic disorder characterized by premature fusion of skull bones).
How Common Is Congenital Aural Atresia?
Congenital aural atresia is not a very common condition. It is seen in one in every 10,000 to 20,000 live births. Congenital aural atresia can affect both ears, but unilateral occurrence is more common than bilateral. Even though unilateral, the condition has more predilection towards the right ear than the left ear. Even though the children with this condition have normal hearing in the unaffected ears, it is seen that they have delayed language development.
What Are the Complications Of Congenital Aural Atresia?
The complications seen in congenital aural atresia are:
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Delayed language development.
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Severe learning disabilities.
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External ear cholesteatomas.
The complications following the surgery of the aural atresia correction include:
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Lateralization of the tympanic membrane graft.
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Restenosis of the canal.
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Temporomandibular joint dysfunction.
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Facial nerve paralysis.
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Taste disturbance.
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Sensorineural hearing loss.
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Conductive hearing loss, infection.
How Is Congenital Aural Atresia Treated or Managed?
The treatment for congenital aural atresia will depend upon factors like hearing status, cosmetic desires, and the feasibility of hearing restoration. Children with bilateral aural atresia will have severe hearing loss, in which children require early bone conduction hearing aids. Whereas in the case of children with unilateral aural atresia, they will have only some amount of hearing loss, they should be closely observed by the teachers and speech therapists to ensure a normal progression of speech and language. They should undergo routine checkups every 6 to 12 months to check for hearing in the unaffected ear.
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Medical Therapy- Other than doing the surgery, this condition can be treated by using amplification devices such as a bone conduction hearing aid with a band worn around the head or normal conventional hearing aid if the auricle structure supports the aid.
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Reconstruction Surgery- The surgery to correct the aural atresia is done following the multistage autologous rib graft reconstructive surgery for microtia. This surgery will also depend upon the age of the child so that the child cooperates with the surgery, postoperative dressing changes, packing removal, and ear canal cleaning to ensure a good result. The reconstruction surgery is done under general anesthesia. The surgery is done by making a postauricular incision into the temporalis fascia. Several grafts with fascia and skin are placed so as to correct the defective affected structure of the ear anatomically.
What Is the Prognosis for Congenital Aural Atresia?
The prognosis for congenital aural atresia will depend upon the severity of the condition and the associated abnormalities. In most cases, they have a favorable prognosis. The most important factors in having a good prognosis are the selection of the patient for the surgery and the surgical technique. Surgery is not recommended for patients with unilateral aural atresia. It is difficult to achieve hearing back to normal following the surgery. The patient will be able to wear a conventional hearing aid in the new canal so as to bring the hearing threshold back to the normal range.
Conclusion
Congenital aural atresia is a condition present in children from the time of birth and affects the development of the external ear canal. Patients with congenital aural atresia can also have congenital microtia. These children can have hearing disabilities and learning disabilities. The parents and the teachers of these children need to take extra care and observe them during their growing age so as to look for their problems.
