Basic anatomical concepts of the ear and functions of the ear The ear consists of three parts: the outer ear, the middle ear, and the inner ear. The outer ear is composed of the funnel-shaped auricle and the external auditory canal. The middle ear is a pneumatic cavity that contains three small auditory bones (hamate, anvil, and stapes) that together form the auditory chain. The inner ear includes the cochlea, whose role is to convert sound into bioelectricity for transmission to the auditory nerve and then to the center. When sound is transmitted to the outer ear, the auricle collects the sound and passes through the external auditory canal to the tympanic membrane, causing the tympanic membrane to vibrate, and the vibration waves are transmitted to the auditory chain, which passes through the hamate, anvil and stapes bones in turn and finally reaches the stapes footplate. The stapes footplate is in contact with the membrane on the oval window and finally passes to the inner ear lymph, where it is converted into a liquid wave and then into bioelectricity via the inner ear. The normal conversational sound intensity is about 45-60 dB, and the whispering sound is about 30 dB. The main concern of patients or their families during ear clinic consultations is their hearing. Some people mistakenly believe that the child is totally deaf, while others think that hearing can be restored by digging an external ear canal. These are misconceptions about microtia. Because the receiving organ of sound (the inner ear) is of different origin than the conducting organ (the outer middle ear) during embryonic development, the inner ear is rarely involved in patients with outer middle ear malformations, so there is still some residual hearing. A fine impactological examination, such as an X-ray, CT or CAT, can sometimes reveal inner ear dysplasia. Brent analyzed nearly 2,500 cases of microtia (nearly 1,500 routine prostheses) and found that only three patients were totally deaf. The problem with hearing in microtia patients is sound conduction. The average patient has a hearing threshold of about 40-60 dB, while the normal hearing threshold is 0-20 dB. Ninety percent of patients with microtia have a normal ear and quickly adapt to hearing in one ear. Their main problem is sound localization and hearing in noisy environments. The teacher should be made to understand the situation and place the child in an appropriate position. Some patients with microtia need speech therapy, and it is also important to keep the normal ear away from harmful noises. It is not necessary to wait for the child to grow up before performing electrical audiometry. In fact, brainstem auditory evoked potential (ABR) tests can be performed on the child shortly after birth to determine if the child’s inner ear is functioning normally and if the middle ear is normal. These tests are also necessary for patients with unilateral microtia, where middle ear deformity may be present even if the contralateral auricle appears to be normal. Because of the presence of a normal inner ear, patients with bilateral malformations can obtain hearing and normal speech development by resolving conduction problems with the use of bone-conduction hearing aids. Bone conduction hearing aids should be fitted within a few weeks of birth and there is no reason to wait several months. Because these bone-conduction hearing aids are larger and make the child look different from his or her peers, it is more desirable to restore hearing through surgery without the need for a hearing aid. However, surgical correction of conduction problems can be very difficult if the middle ear is developing abnormally. During hearing reconstruction surgery, care must be taken to avoid damaging the facial nerve when removing bone, while grafting fascia and skin to reconstruct the tympanic membrane. Malformed or fused auditory chains sometimes cannot be repaired and other auditory chain reconstruction techniques need to be applied. The grafted skin is implanted in the drilled bony external auditory canal, with the possibility of chronic oozing and restenosis of the external auditory canal. Of course, in the hands of otologists with a great deal of clinical experience, surgical restoration of middle ear function can still be valuable for patients with microtia. Because of the surgical technique and hearing issues mentioned above, many plastic surgeons feel that the benefits gained from middle ear surgery are less than the risks and complications, and that this surgery should be done only for patients with binaural malformations. In reality, this procedure requires extensive experience and expertise in otologic surgery, as well as the surgeon’s skill and ability to assess the patient’s middle ear development in order to determine suitability for the procedure. Jahrsdoerfer uses a scoring system to analyze CT films to assess each patient’s middle ear development and considers a score of 6 or higher for monaural cases to be an but in patients with binaural malformations, middle ear surgery can be considered even if the score is below 6. Based on Jahrsdoerfer’s criteria, we have found that approximately 50% of patients are suitable for surgery. These criteria not only help predict the probability of success (for example, a score of 8 has an 80% chance of restoring or approximating restoration of hearing, or 15-25 dB), but also prevent unsuitable cases from being incorrectly operated on. Often auricular reconstruction precedes middle ear surgery because once external canal or middle ear surgery is attempted, the original skin is scarred, jeopardizing the safety of the auricular reconstruction. Unless Ear canal reconstruction and ossicular reconstruction are performed at the same time.