ear, nose, and throat disorders
Developmental Abnormalities of the Outer Ear
Auditory canal atresia
Auditory canal atresia is the partial or total failure of the ear canal to develop. Absence of the ear canal is usually associated with absence of the eardrum (tympanic membrane) and underdevelopment of the Middle Ear (hammer, anvil, and stirrup bones). Children with auditory canal atresia have hearing loss because sound is not efficiently carried, or conducted, into the middle and inner ear. Usually the inner ear (cochlea) is healthy and normally developed in these children. In some children, doctors can surgically open the ear canal, build an eardrum, and restore the natural sound-conducting pathway of the ear canal and middle ear to the healthy inner ear. Although surgical correction of auditory canal atresia, called canalplasty, can improve hearing, it seldom results in normal hearing at all pitches (frequencies) of sound. Bone-conducting hearing devicescan also be used to treat auditory canal atresia. These devices conduct sound to the inner ear by vibrating the bone of the skull. These hearing devices are attached to a hard metal or soft band that is worn tightly around the head. A bone-conducting hearing device is important for normal development of speech and language in children with auditory canal atresia in both ears. Specialimplantable bone-anchored devicesare becoming popular as an alternative to bone-conducting hearing devices worn on a soft or hard band. These devices are attached to titanium posts or magnetic plates that are surgically anchored into the skull bone (hence the term, "bone anchored hearing device"). In the United States, the Food and Drug Administration (FDA) approved these surgically placed devices for children 5 years and older. The key feature of these devices is that they must make close contact with the bone of the skull to conduct sound efficiently to the inner ear. 