[Indications and surgical treatment of large middle ear abnormality].

Children with atresia of the external auditory canal should undergo hearing assessment and fitting of a bone conduction hearing aid as early as possible to allow speech to develop normally. Surgery is done between 5 and 6 years of age, guided by high-resolution computed tomography, which provides a more precise diagnosis based on the abnormalities seen. The temporomandibular joint lies more posteriorly than normal due to aplasia or hypoplasia of the tympanic bone, so that the middle ear must be approached through the mastoid, resulting in a less favourable coupling to the middle ear structures. In unfavourable cases bone anchored hearing aids, creation of a meatus for fitting a hearing aid or a bone conduction hearing aid must be considered.