Congenital stenosis or atresia of the external auditory canal is a rare congenital disorder that often occurs with microtia, often due to gill arch dysplasia after 20 days of pregnancy, most often due to environmental factors (viral infections, drugs, or radiation) rather than genetics.
Due to the obstruction of the external auditory canal, the channel that normally transmits sound to the eardrum is blocked by bone and other tissues, and these additional tissues will also connect with the ossicle, further aggravating the difficulty of sound transmission, resulting in severe conductive hearing loss in children, and when the disease occurs bilaterally, it will also seriously affect the normal development of speech. Even unilateral onset can affect sound localization and voice pickup in noisy environments.
When the child is 5 years old, the temporal bone sutures of the temporal bone where the hearing structure is located are closed, the size is close to **, and psychologically has been able to actively cooperate with the doctor, the international medical community generally believes that at this time, external auditory canal surgery can be considered to achieve hearing**. After surgery, hearing ** can not only hear sounds clearly, especially in noisy environments, but also listen as early as possible**, forming binaural stereo sound, which can enhance the localization ability of sound, and promote the balanced development of the brain's central body for receiving and feeling sound (before the age of 7, the brain auditory center develops**).
Ear canaloplasty is an important method of hearing reconstruction, which reconstructs the complete ear canal and reconstructs the middle ear structures such as the tympanic membrane and ossicular bone for sound transmission, so as to restore the child's voice conduction function. The normal ear canal originates from the external auricular hilum and extends inward to the tympanic membrane, and is about 2 years long5～3.5 cm, divided into cartilage segment and bony segment, cartilage segment occupies about the lateral 1 3, bony segment occupies the medial 2 3. The cartilage segment of the external auditory canal** contains cerumen glands, and the secreted cerumen can effectively inhibit the reproduction of bacteria. The bony segment lacks hair follicles and other structures, similar to the Yingke pine in the crevices of Huangshan, and a thin layer of epithelium grows very tenaciously on the bone.
Through a large number of clinical research data, a set of preoperative evaluation system based on CT image data has been summarized, which can be used to improve the effect of hearing loss caused by atresia of the external auditory canal in advance. At present, the most commonly used is the Jahrsdorfer score, which is a scoring system that designs the 9 structures of the external auditory canal and middle ear into a 10-point scale (2 points for the stapes and 1 point for the rest of the structures).
External auditory canal plasty surgery involves a series of technical fine operations including temporal bone osteometry, ossicular release or reconstruction, and transplantation, with a high technical threshold, which is a typical example of making the best use of things in modern medicine, such as making full use of materials such as the original ear and the ear canal from the surface to the inside, perichondrium, cartilage and periosteum and other materials into the repair of this operation, in addition to the thickness of the hair under the premise of "unscathed".2-0.A 3mm scalp graft becomes a new external auditory canal**. Since the skin taken from the scalp is very thin, it ensures that the scalp at the place of peel removal does not have any scars, and does not damage any hair follicles on the scalp, and after transplantation into the external ear canal, there will be no rejection reaction and no annoying hair.
According to my extensive experience with the results of surgical patients, generally two to three months after surgery (some teams at home and abroad have reported that it will take half a year after surgery), the newly created external auditory canal** and tympanic membrane tend to stabilize, and then the child can return to the same life as a normal child, in addition to being able to return to the world of clear sound, to the children's happiness, they can even swim in the groundwater without worry.